| /* |
| * Copyright (C) 1999 Eric Youngdale |
| * Copyright (C) 2014 Christoph Hellwig |
| * |
| * SCSI queueing library. |
| * Initial versions: Eric Youngdale (eric@andante.org). |
| * Based upon conversations with large numbers |
| * of people at Linux Expo. |
| */ |
| |
| #include <linux/bio.h> |
| #include <linux/bitops.h> |
| #include <linux/blkdev.h> |
| #include <linux/completion.h> |
| #include <linux/kernel.h> |
| #include <linux/export.h> |
| #include <linux/init.h> |
| #include <linux/pci.h> |
| #include <linux/delay.h> |
| #include <linux/hardirq.h> |
| #include <linux/scatterlist.h> |
| #include <linux/blk-mq.h> |
| #include <linux/ratelimit.h> |
| #include <asm/unaligned.h> |
| |
| #include <scsi/scsi.h> |
| #include <scsi/scsi_cmnd.h> |
| #include <scsi/scsi_dbg.h> |
| #include <scsi/scsi_device.h> |
| #include <scsi/scsi_driver.h> |
| #include <scsi/scsi_eh.h> |
| #include <scsi/scsi_host.h> |
| #include <scsi/scsi_transport.h> /* __scsi_init_queue() */ |
| #include <scsi/scsi_dh.h> |
| |
| #include <trace/events/scsi.h> |
| |
| #include "scsi_debugfs.h" |
| #include "scsi_priv.h" |
| #include "scsi_logging.h" |
| |
| static struct kmem_cache *scsi_sdb_cache; |
| static struct kmem_cache *scsi_sense_cache; |
| static struct kmem_cache *scsi_sense_isadma_cache; |
| static DEFINE_MUTEX(scsi_sense_cache_mutex); |
| |
| static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd); |
| |
| static inline struct kmem_cache * |
| scsi_select_sense_cache(bool unchecked_isa_dma) |
| { |
| return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache; |
| } |
| |
| static void scsi_free_sense_buffer(bool unchecked_isa_dma, |
| unsigned char *sense_buffer) |
| { |
| kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma), |
| sense_buffer); |
| } |
| |
| static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma, |
| gfp_t gfp_mask, int numa_node) |
| { |
| return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma), |
| gfp_mask, numa_node); |
| } |
| |
| int scsi_init_sense_cache(struct Scsi_Host *shost) |
| { |
| struct kmem_cache *cache; |
| int ret = 0; |
| |
| cache = scsi_select_sense_cache(shost->unchecked_isa_dma); |
| if (cache) |
| return 0; |
| |
| mutex_lock(&scsi_sense_cache_mutex); |
| if (shost->unchecked_isa_dma) { |
| scsi_sense_isadma_cache = |
| kmem_cache_create("scsi_sense_cache(DMA)", |
| SCSI_SENSE_BUFFERSIZE, 0, |
| SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL); |
| if (!scsi_sense_isadma_cache) |
| ret = -ENOMEM; |
| } else { |
| scsi_sense_cache = |
| kmem_cache_create_usercopy("scsi_sense_cache", |
| SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, |
| 0, SCSI_SENSE_BUFFERSIZE, NULL); |
| if (!scsi_sense_cache) |
| ret = -ENOMEM; |
| } |
| |
| mutex_unlock(&scsi_sense_cache_mutex); |
| return ret; |
| } |
| |
| /* |
| * When to reinvoke queueing after a resource shortage. It's 3 msecs to |
| * not change behaviour from the previous unplug mechanism, experimentation |
| * may prove this needs changing. |
| */ |
| #define SCSI_QUEUE_DELAY 3 |
| |
| static void |
| scsi_set_blocked(struct scsi_cmnd *cmd, int reason) |
| { |
| struct Scsi_Host *host = cmd->device->host; |
| struct scsi_device *device = cmd->device; |
| struct scsi_target *starget = scsi_target(device); |
| |
| /* |
| * Set the appropriate busy bit for the device/host. |
| * |
| * If the host/device isn't busy, assume that something actually |
| * completed, and that we should be able to queue a command now. |
| * |
| * Note that the prior mid-layer assumption that any host could |
| * always queue at least one command is now broken. The mid-layer |
| * will implement a user specifiable stall (see |
| * scsi_host.max_host_blocked and scsi_device.max_device_blocked) |
| * if a command is requeued with no other commands outstanding |
| * either for the device or for the host. |
| */ |
| switch (reason) { |
| case SCSI_MLQUEUE_HOST_BUSY: |
| atomic_set(&host->host_blocked, host->max_host_blocked); |
| break; |
| case SCSI_MLQUEUE_DEVICE_BUSY: |
| case SCSI_MLQUEUE_EH_RETRY: |
| atomic_set(&device->device_blocked, |
| device->max_device_blocked); |
| break; |
| case SCSI_MLQUEUE_TARGET_BUSY: |
| atomic_set(&starget->target_blocked, |
| starget->max_target_blocked); |
| break; |
| } |
| } |
| |
| static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd) |
| { |
| struct scsi_device *sdev = cmd->device; |
| |
| if (cmd->request->rq_flags & RQF_DONTPREP) { |
| cmd->request->rq_flags &= ~RQF_DONTPREP; |
| scsi_mq_uninit_cmd(cmd); |
| } else { |
| WARN_ON_ONCE(true); |
| } |
| blk_mq_requeue_request(cmd->request, true); |
| put_device(&sdev->sdev_gendev); |
| } |
| |
| /** |
| * __scsi_queue_insert - private queue insertion |
| * @cmd: The SCSI command being requeued |
| * @reason: The reason for the requeue |
| * @unbusy: Whether the queue should be unbusied |
| * |
| * This is a private queue insertion. The public interface |
| * scsi_queue_insert() always assumes the queue should be unbusied |
| * because it's always called before the completion. This function is |
| * for a requeue after completion, which should only occur in this |
| * file. |
| */ |
| static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy) |
| { |
| struct scsi_device *device = cmd->device; |
| struct request_queue *q = device->request_queue; |
| unsigned long flags; |
| |
| SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd, |
| "Inserting command %p into mlqueue\n", cmd)); |
| |
| scsi_set_blocked(cmd, reason); |
| |
| /* |
| * Decrement the counters, since these commands are no longer |
| * active on the host/device. |
| */ |
| if (unbusy) |
| scsi_device_unbusy(device); |
| |
| /* |
| * Requeue this command. It will go before all other commands |
| * that are already in the queue. Schedule requeue work under |
| * lock such that the kblockd_schedule_work() call happens |
| * before blk_cleanup_queue() finishes. |
| */ |
| cmd->result = 0; |
| if (q->mq_ops) { |
| /* |
| * Before a SCSI command is dispatched, |
| * get_device(&sdev->sdev_gendev) is called and the host, |
| * target and device busy counters are increased. Since |
| * requeuing a request causes these actions to be repeated and |
| * since scsi_device_unbusy() has already been called, |
| * put_device(&device->sdev_gendev) must still be called. Call |
| * put_device() after blk_mq_requeue_request() to avoid that |
| * removal of the SCSI device can start before requeueing has |
| * happened. |
| */ |
| blk_mq_requeue_request(cmd->request, true); |
| put_device(&device->sdev_gendev); |
| return; |
| } |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_requeue_request(q, cmd->request); |
| kblockd_schedule_work(&device->requeue_work); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| |
| /* |
| * Function: scsi_queue_insert() |
| * |
| * Purpose: Insert a command in the midlevel queue. |
| * |
| * Arguments: cmd - command that we are adding to queue. |
| * reason - why we are inserting command to queue. |
| * |
| * Lock status: Assumed that lock is not held upon entry. |
| * |
| * Returns: Nothing. |
| * |
| * Notes: We do this for one of two cases. Either the host is busy |
| * and it cannot accept any more commands for the time being, |
| * or the device returned QUEUE_FULL and can accept no more |
| * commands. |
| * Notes: This could be called either from an interrupt context or a |
| * normal process context. |
| */ |
| void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) |
| { |
| __scsi_queue_insert(cmd, reason, true); |
| } |
| |
| |
| /** |
| * __scsi_execute - insert request and wait for the result |
| * @sdev: scsi device |
| * @cmd: scsi command |
| * @data_direction: data direction |
| * @buffer: data buffer |
| * @bufflen: len of buffer |
| * @sense: optional sense buffer |
| * @sshdr: optional decoded sense header |
| * @timeout: request timeout in seconds |
| * @retries: number of times to retry request |
| * @flags: flags for ->cmd_flags |
| * @rq_flags: flags for ->rq_flags |
| * @resid: optional residual length |
| * |
| * Returns the scsi_cmnd result field if a command was executed, or a negative |
| * Linux error code if we didn't get that far. |
| */ |
| int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
| int data_direction, void *buffer, unsigned bufflen, |
| unsigned char *sense, struct scsi_sense_hdr *sshdr, |
| int timeout, int retries, u64 flags, req_flags_t rq_flags, |
| int *resid) |
| { |
| struct request *req; |
| struct scsi_request *rq; |
| int ret = DRIVER_ERROR << 24; |
| |
| req = blk_get_request(sdev->request_queue, |
| data_direction == DMA_TO_DEVICE ? |
| REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT); |
| if (IS_ERR(req)) |
| return ret; |
| rq = scsi_req(req); |
| |
| if (bufflen && blk_rq_map_kern(sdev->request_queue, req, |
| buffer, bufflen, GFP_NOIO)) |
| goto out; |
| |
| rq->cmd_len = COMMAND_SIZE(cmd[0]); |
| memcpy(rq->cmd, cmd, rq->cmd_len); |
| rq->retries = retries; |
| req->timeout = timeout; |
| req->cmd_flags |= flags; |
| req->rq_flags |= rq_flags | RQF_QUIET; |
| |
| /* |
| * head injection *required* here otherwise quiesce won't work |
| */ |
| blk_execute_rq(req->q, NULL, req, 1); |
| |
| /* |
| * Some devices (USB mass-storage in particular) may transfer |
| * garbage data together with a residue indicating that the data |
| * is invalid. Prevent the garbage from being misinterpreted |
| * and prevent security leaks by zeroing out the excess data. |
| */ |
| if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen)) |
| memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len); |
| |
| if (resid) |
| *resid = rq->resid_len; |
| if (sense && rq->sense_len) |
| memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE); |
| if (sshdr) |
| scsi_normalize_sense(rq->sense, rq->sense_len, sshdr); |
| ret = rq->result; |
| out: |
| blk_put_request(req); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(__scsi_execute); |
| |
| /* |
| * Function: scsi_init_cmd_errh() |
| * |
| * Purpose: Initialize cmd fields related to error handling. |
| * |
| * Arguments: cmd - command that is ready to be queued. |
| * |
| * Notes: This function has the job of initializing a number of |
| * fields related to error handling. Typically this will |
| * be called once for each command, as required. |
| */ |
| static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) |
| { |
| cmd->serial_number = 0; |
| scsi_set_resid(cmd, 0); |
| memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); |
| if (cmd->cmd_len == 0) |
| cmd->cmd_len = scsi_command_size(cmd->cmnd); |
| } |
| |
| /* |
| * Decrement the host_busy counter and wake up the error handler if necessary. |
| * Avoid as follows that the error handler is not woken up if shost->host_busy |
| * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination |
| * with an RCU read lock in this function to ensure that this function in its |
| * entirety either finishes before scsi_eh_scmd_add() increases the |
| * host_failed counter or that it notices the shost state change made by |
| * scsi_eh_scmd_add(). |
| */ |
| static void scsi_dec_host_busy(struct Scsi_Host *shost) |
| { |
| unsigned long flags; |
| |
| rcu_read_lock(); |
| atomic_dec(&shost->host_busy); |
| if (unlikely(scsi_host_in_recovery(shost))) { |
| spin_lock_irqsave(shost->host_lock, flags); |
| if (shost->host_failed || shost->host_eh_scheduled) |
| scsi_eh_wakeup(shost); |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| } |
| rcu_read_unlock(); |
| } |
| |
| void scsi_device_unbusy(struct scsi_device *sdev) |
| { |
| struct Scsi_Host *shost = sdev->host; |
| struct scsi_target *starget = scsi_target(sdev); |
| |
| scsi_dec_host_busy(shost); |
| |
| if (starget->can_queue > 0) |
| atomic_dec(&starget->target_busy); |
| |
| atomic_dec(&sdev->device_busy); |
| } |
| |
| static void scsi_kick_queue(struct request_queue *q) |
| { |
| if (q->mq_ops) |
| blk_mq_run_hw_queues(q, false); |
| else |
| blk_run_queue(q); |
| } |
| |
| /* |
| * Called for single_lun devices on IO completion. Clear starget_sdev_user, |
| * and call blk_run_queue for all the scsi_devices on the target - |
| * including current_sdev first. |
| * |
| * Called with *no* scsi locks held. |
| */ |
| static void scsi_single_lun_run(struct scsi_device *current_sdev) |
| { |
| struct Scsi_Host *shost = current_sdev->host; |
| struct scsi_device *sdev, *tmp; |
| struct scsi_target *starget = scsi_target(current_sdev); |
| unsigned long flags; |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| starget->starget_sdev_user = NULL; |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| |
| /* |
| * Call blk_run_queue for all LUNs on the target, starting with |
| * current_sdev. We race with others (to set starget_sdev_user), |
| * but in most cases, we will be first. Ideally, each LU on the |
| * target would get some limited time or requests on the target. |
| */ |
| scsi_kick_queue(current_sdev->request_queue); |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| if (starget->starget_sdev_user) |
| goto out; |
| list_for_each_entry_safe(sdev, tmp, &starget->devices, |
| same_target_siblings) { |
| if (sdev == current_sdev) |
| continue; |
| if (scsi_device_get(sdev)) |
| continue; |
| |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| scsi_kick_queue(sdev->request_queue); |
| spin_lock_irqsave(shost->host_lock, flags); |
| |
| scsi_device_put(sdev); |
| } |
| out: |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| } |
| |
| static inline bool scsi_device_is_busy(struct scsi_device *sdev) |
| { |
| if (atomic_read(&sdev->device_busy) >= sdev->queue_depth) |
| return true; |
| if (atomic_read(&sdev->device_blocked) > 0) |
| return true; |
| return false; |
| } |
| |
| static inline bool scsi_target_is_busy(struct scsi_target *starget) |
| { |
| if (starget->can_queue > 0) { |
| if (atomic_read(&starget->target_busy) >= starget->can_queue) |
| return true; |
| if (atomic_read(&starget->target_blocked) > 0) |
| return true; |
| } |
| return false; |
| } |
| |
| static inline bool scsi_host_is_busy(struct Scsi_Host *shost) |
| { |
| if (shost->can_queue > 0 && |
| atomic_read(&shost->host_busy) >= shost->can_queue) |
| return true; |
| if (atomic_read(&shost->host_blocked) > 0) |
| return true; |
| if (shost->host_self_blocked) |
| return true; |
| return false; |
| } |
| |
| static void scsi_starved_list_run(struct Scsi_Host *shost) |
| { |
| LIST_HEAD(starved_list); |
| struct scsi_device *sdev; |
| unsigned long flags; |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| list_splice_init(&shost->starved_list, &starved_list); |
| |
| while (!list_empty(&starved_list)) { |
| struct request_queue *slq; |
| |
| /* |
| * As long as shost is accepting commands and we have |
| * starved queues, call blk_run_queue. scsi_request_fn |
| * drops the queue_lock and can add us back to the |
| * starved_list. |
| * |
| * host_lock protects the starved_list and starved_entry. |
| * scsi_request_fn must get the host_lock before checking |
| * or modifying starved_list or starved_entry. |
| */ |
| if (scsi_host_is_busy(shost)) |
| break; |
| |
| sdev = list_entry(starved_list.next, |
| struct scsi_device, starved_entry); |
| list_del_init(&sdev->starved_entry); |
| if (scsi_target_is_busy(scsi_target(sdev))) { |
| list_move_tail(&sdev->starved_entry, |
| &shost->starved_list); |
| continue; |
| } |
| |
| /* |
| * Once we drop the host lock, a racing scsi_remove_device() |
| * call may remove the sdev from the starved list and destroy |
| * it and the queue. Mitigate by taking a reference to the |
| * queue and never touching the sdev again after we drop the |
| * host lock. Note: if __scsi_remove_device() invokes |
| * blk_cleanup_queue() before the queue is run from this |
| * function then blk_run_queue() will return immediately since |
| * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING. |
| */ |
| slq = sdev->request_queue; |
| if (!blk_get_queue(slq)) |
| continue; |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| |
| scsi_kick_queue(slq); |
| blk_put_queue(slq); |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| } |
| /* put any unprocessed entries back */ |
| list_splice(&starved_list, &shost->starved_list); |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| } |
| |
| /* |
| * Function: scsi_run_queue() |
| * |
| * Purpose: Select a proper request queue to serve next |
| * |
| * Arguments: q - last request's queue |
| * |
| * Returns: Nothing |
| * |
| * Notes: The previous command was completely finished, start |
| * a new one if possible. |
| */ |
| static void scsi_run_queue(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| |
| if (scsi_target(sdev)->single_lun) |
| scsi_single_lun_run(sdev); |
| if (!list_empty(&sdev->host->starved_list)) |
| scsi_starved_list_run(sdev->host); |
| |
| if (q->mq_ops) |
| blk_mq_run_hw_queues(q, false); |
| else |
| blk_run_queue(q); |
| } |
| |
| void scsi_requeue_run_queue(struct work_struct *work) |
| { |
| struct scsi_device *sdev; |
| struct request_queue *q; |
| |
| sdev = container_of(work, struct scsi_device, requeue_work); |
| q = sdev->request_queue; |
| scsi_run_queue(q); |
| } |
| |
| /* |
| * Function: scsi_requeue_command() |
| * |
| * Purpose: Handle post-processing of completed commands. |
| * |
| * Arguments: q - queue to operate on |
| * cmd - command that may need to be requeued. |
| * |
| * Returns: Nothing |
| * |
| * Notes: After command completion, there may be blocks left |
| * over which weren't finished by the previous command |
| * this can be for a number of reasons - the main one is |
| * I/O errors in the middle of the request, in which case |
| * we need to request the blocks that come after the bad |
| * sector. |
| * Notes: Upon return, cmd is a stale pointer. |
| */ |
| static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) |
| { |
| struct scsi_device *sdev = cmd->device; |
| struct request *req = cmd->request; |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_unprep_request(req); |
| req->special = NULL; |
| scsi_put_command(cmd); |
| blk_requeue_request(q, req); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| scsi_run_queue(q); |
| |
| put_device(&sdev->sdev_gendev); |
| } |
| |
| void scsi_run_host_queues(struct Scsi_Host *shost) |
| { |
| struct scsi_device *sdev; |
| |
| shost_for_each_device(sdev, shost) |
| scsi_run_queue(sdev->request_queue); |
| } |
| |
| static void scsi_uninit_cmd(struct scsi_cmnd *cmd) |
| { |
| if (!blk_rq_is_passthrough(cmd->request)) { |
| struct scsi_driver *drv = scsi_cmd_to_driver(cmd); |
| |
| if (drv->uninit_command) |
| drv->uninit_command(cmd); |
| } |
| } |
| |
| static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd) |
| { |
| struct scsi_data_buffer *sdb; |
| |
| if (cmd->sdb.table.nents) |
| sg_free_table_chained(&cmd->sdb.table, true); |
| if (cmd->request->next_rq) { |
| sdb = cmd->request->next_rq->special; |
| if (sdb) |
| sg_free_table_chained(&sdb->table, true); |
| } |
| if (scsi_prot_sg_count(cmd)) |
| sg_free_table_chained(&cmd->prot_sdb->table, true); |
| } |
| |
| static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd) |
| { |
| scsi_mq_free_sgtables(cmd); |
| scsi_uninit_cmd(cmd); |
| scsi_del_cmd_from_list(cmd); |
| } |
| |
| /* |
| * Function: scsi_release_buffers() |
| * |
| * Purpose: Free resources allocate for a scsi_command. |
| * |
| * Arguments: cmd - command that we are bailing. |
| * |
| * Lock status: Assumed that no lock is held upon entry. |
| * |
| * Returns: Nothing |
| * |
| * Notes: In the event that an upper level driver rejects a |
| * command, we must release resources allocated during |
| * the __init_io() function. Primarily this would involve |
| * the scatter-gather table. |
| */ |
| static void scsi_release_buffers(struct scsi_cmnd *cmd) |
| { |
| if (cmd->sdb.table.nents) |
| sg_free_table_chained(&cmd->sdb.table, false); |
| |
| memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
| |
| if (scsi_prot_sg_count(cmd)) |
| sg_free_table_chained(&cmd->prot_sdb->table, false); |
| } |
| |
| static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd) |
| { |
| struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special; |
| |
| sg_free_table_chained(&bidi_sdb->table, false); |
| kmem_cache_free(scsi_sdb_cache, bidi_sdb); |
| cmd->request->next_rq->special = NULL; |
| } |
| |
| /* Returns false when no more bytes to process, true if there are more */ |
| static bool scsi_end_request(struct request *req, blk_status_t error, |
| unsigned int bytes, unsigned int bidi_bytes) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| struct scsi_device *sdev = cmd->device; |
| struct request_queue *q = sdev->request_queue; |
| |
| if (blk_update_request(req, error, bytes)) |
| return true; |
| |
| /* Bidi request must be completed as a whole */ |
| if (unlikely(bidi_bytes) && |
| blk_update_request(req->next_rq, error, bidi_bytes)) |
| return true; |
| |
| if (blk_queue_add_random(q)) |
| add_disk_randomness(req->rq_disk); |
| |
| if (!blk_rq_is_scsi(req)) { |
| WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED)); |
| cmd->flags &= ~SCMD_INITIALIZED; |
| destroy_rcu_head(&cmd->rcu); |
| } |
| |
| if (req->mq_ctx) { |
| /* |
| * In the MQ case the command gets freed by __blk_mq_end_request, |
| * so we have to do all cleanup that depends on it earlier. |
| * |
| * We also can't kick the queues from irq context, so we |
| * will have to defer it to a workqueue. |
| */ |
| scsi_mq_uninit_cmd(cmd); |
| |
| __blk_mq_end_request(req, error); |
| |
| if (scsi_target(sdev)->single_lun || |
| !list_empty(&sdev->host->starved_list)) |
| kblockd_schedule_work(&sdev->requeue_work); |
| else |
| blk_mq_run_hw_queues(q, true); |
| } else { |
| unsigned long flags; |
| |
| if (bidi_bytes) |
| scsi_release_bidi_buffers(cmd); |
| scsi_release_buffers(cmd); |
| scsi_put_command(cmd); |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_finish_request(req, error); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| scsi_run_queue(q); |
| } |
| |
| put_device(&sdev->sdev_gendev); |
| return false; |
| } |
| |
| /** |
| * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t |
| * @cmd: SCSI command |
| * @result: scsi error code |
| * |
| * Translate a SCSI result code into a blk_status_t value. May reset the host |
| * byte of @cmd->result. |
| */ |
| static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result) |
| { |
| switch (host_byte(result)) { |
| case DID_OK: |
| /* |
| * Also check the other bytes than the status byte in result |
| * to handle the case when a SCSI LLD sets result to |
| * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION. |
| */ |
| if (scsi_status_is_good(result) && (result & ~0xff) == 0) |
| return BLK_STS_OK; |
| return BLK_STS_IOERR; |
| case DID_TRANSPORT_FAILFAST: |
| return BLK_STS_TRANSPORT; |
| case DID_TARGET_FAILURE: |
| set_host_byte(cmd, DID_OK); |
| return BLK_STS_TARGET; |
| case DID_NEXUS_FAILURE: |
| return BLK_STS_NEXUS; |
| case DID_ALLOC_FAILURE: |
| set_host_byte(cmd, DID_OK); |
| return BLK_STS_NOSPC; |
| case DID_MEDIUM_ERROR: |
| set_host_byte(cmd, DID_OK); |
| return BLK_STS_MEDIUM; |
| default: |
| return BLK_STS_IOERR; |
| } |
| } |
| |
| /* Helper for scsi_io_completion() when "reprep" action required. */ |
| static void scsi_io_completion_reprep(struct scsi_cmnd *cmd, |
| struct request_queue *q) |
| { |
| /* A new command will be prepared and issued. */ |
| if (q->mq_ops) { |
| scsi_mq_requeue_cmd(cmd); |
| } else { |
| /* Unprep request and put it back at head of the queue. */ |
| scsi_release_buffers(cmd); |
| scsi_requeue_command(q, cmd); |
| } |
| } |
| |
| /* Helper for scsi_io_completion() when special action required. */ |
| static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) |
| { |
| struct request_queue *q = cmd->device->request_queue; |
| struct request *req = cmd->request; |
| int level = 0; |
| enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, |
| ACTION_DELAYED_RETRY} action; |
| unsigned long wait_for = (cmd->allowed + 1) * req->timeout; |
| struct scsi_sense_hdr sshdr; |
| bool sense_valid; |
| bool sense_current = true; /* false implies "deferred sense" */ |
| blk_status_t blk_stat; |
| |
| sense_valid = scsi_command_normalize_sense(cmd, &sshdr); |
| if (sense_valid) |
| sense_current = !scsi_sense_is_deferred(&sshdr); |
| |
| blk_stat = scsi_result_to_blk_status(cmd, result); |
| |
| if (host_byte(result) == DID_RESET) { |
| /* Third party bus reset or reset for error recovery |
| * reasons. Just retry the command and see what |
| * happens. |
| */ |
| action = ACTION_RETRY; |
| } else if (sense_valid && sense_current) { |
| switch (sshdr.sense_key) { |
| case UNIT_ATTENTION: |
| if (cmd->device->removable) { |
| /* Detected disc change. Set a bit |
| * and quietly refuse further access. |
| */ |
| cmd->device->changed = 1; |
| action = ACTION_FAIL; |
| } else { |
| /* Must have been a power glitch, or a |
| * bus reset. Could not have been a |
| * media change, so we just retry the |
| * command and see what happens. |
| */ |
| action = ACTION_RETRY; |
| } |
| break; |
| case ILLEGAL_REQUEST: |
| /* If we had an ILLEGAL REQUEST returned, then |
| * we may have performed an unsupported |
| * command. The only thing this should be |
| * would be a ten byte read where only a six |
| * byte read was supported. Also, on a system |
| * where READ CAPACITY failed, we may have |
| * read past the end of the disk. |
| */ |
| if ((cmd->device->use_10_for_rw && |
| sshdr.asc == 0x20 && sshdr.ascq == 0x00) && |
| (cmd->cmnd[0] == READ_10 || |
| cmd->cmnd[0] == WRITE_10)) { |
| /* This will issue a new 6-byte command. */ |
| cmd->device->use_10_for_rw = 0; |
| action = ACTION_REPREP; |
| } else if (sshdr.asc == 0x10) /* DIX */ { |
| action = ACTION_FAIL; |
| blk_stat = BLK_STS_PROTECTION; |
| /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ |
| } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) { |
| action = ACTION_FAIL; |
| blk_stat = BLK_STS_TARGET; |
| } else |
| action = ACTION_FAIL; |
| break; |
| case ABORTED_COMMAND: |
| action = ACTION_FAIL; |
| if (sshdr.asc == 0x10) /* DIF */ |
| blk_stat = BLK_STS_PROTECTION; |
| break; |
| case NOT_READY: |
| /* If the device is in the process of becoming |
| * ready, or has a temporary blockage, retry. |
| */ |
| if (sshdr.asc == 0x04) { |
| switch (sshdr.ascq) { |
| case 0x01: /* becoming ready */ |
| case 0x04: /* format in progress */ |
| case 0x05: /* rebuild in progress */ |
| case 0x06: /* recalculation in progress */ |
| case 0x07: /* operation in progress */ |
| case 0x08: /* Long write in progress */ |
| case 0x09: /* self test in progress */ |
| case 0x14: /* space allocation in progress */ |
| case 0x1a: /* start stop unit in progress */ |
| case 0x1b: /* sanitize in progress */ |
| case 0x1d: /* configuration in progress */ |
| case 0x24: /* depopulation in progress */ |
| action = ACTION_DELAYED_RETRY; |
| break; |
| default: |
| action = ACTION_FAIL; |
| break; |
| } |
| } else |
| action = ACTION_FAIL; |
| break; |
| case VOLUME_OVERFLOW: |
| /* See SSC3rXX or current. */ |
| action = ACTION_FAIL; |
| break; |
| default: |
| action = ACTION_FAIL; |
| break; |
| } |
| } else |
| action = ACTION_FAIL; |
| |
| if (action != ACTION_FAIL && |
| time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) |
| action = ACTION_FAIL; |
| |
| switch (action) { |
| case ACTION_FAIL: |
| /* Give up and fail the remainder of the request */ |
| if (!(req->rq_flags & RQF_QUIET)) { |
| static DEFINE_RATELIMIT_STATE(_rs, |
| DEFAULT_RATELIMIT_INTERVAL, |
| DEFAULT_RATELIMIT_BURST); |
| |
| if (unlikely(scsi_logging_level)) |
| level = |
| SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, |
| SCSI_LOG_MLCOMPLETE_BITS); |
| |
| /* |
| * if logging is enabled the failure will be printed |
| * in scsi_log_completion(), so avoid duplicate messages |
| */ |
| if (!level && __ratelimit(&_rs)) { |
| scsi_print_result(cmd, NULL, FAILED); |
| if (driver_byte(result) == DRIVER_SENSE) |
| scsi_print_sense(cmd); |
| scsi_print_command(cmd); |
| } |
| } |
| if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req), 0)) |
| return; |
| /*FALLTHRU*/ |
| case ACTION_REPREP: |
| scsi_io_completion_reprep(cmd, q); |
| break; |
| case ACTION_RETRY: |
| /* Retry the same command immediately */ |
| __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false); |
| break; |
| case ACTION_DELAYED_RETRY: |
| /* Retry the same command after a delay */ |
| __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false); |
| break; |
| } |
| } |
| |
| /* |
| * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a |
| * new result that may suppress further error checking. Also modifies |
| * *blk_statp in some cases. |
| */ |
| static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result, |
| blk_status_t *blk_statp) |
| { |
| bool sense_valid; |
| bool sense_current = true; /* false implies "deferred sense" */ |
| struct request *req = cmd->request; |
| struct scsi_sense_hdr sshdr; |
| |
| sense_valid = scsi_command_normalize_sense(cmd, &sshdr); |
| if (sense_valid) |
| sense_current = !scsi_sense_is_deferred(&sshdr); |
| |
| if (blk_rq_is_passthrough(req)) { |
| if (sense_valid) { |
| /* |
| * SG_IO wants current and deferred errors |
| */ |
| scsi_req(req)->sense_len = |
| min(8 + cmd->sense_buffer[7], |
| SCSI_SENSE_BUFFERSIZE); |
| } |
| if (sense_current) |
| *blk_statp = scsi_result_to_blk_status(cmd, result); |
| } else if (blk_rq_bytes(req) == 0 && sense_current) { |
| /* |
| * Flush commands do not transfers any data, and thus cannot use |
| * good_bytes != blk_rq_bytes(req) as the signal for an error. |
| * This sets *blk_statp explicitly for the problem case. |
| */ |
| *blk_statp = scsi_result_to_blk_status(cmd, result); |
| } |
| /* |
| * Recovered errors need reporting, but they're always treated as |
| * success, so fiddle the result code here. For passthrough requests |
| * we already took a copy of the original into sreq->result which |
| * is what gets returned to the user |
| */ |
| if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { |
| bool do_print = true; |
| /* |
| * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d] |
| * skip print since caller wants ATA registers. Only occurs |
| * on SCSI ATA PASS_THROUGH commands when CK_COND=1 |
| */ |
| if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) |
| do_print = false; |
| else if (req->rq_flags & RQF_QUIET) |
| do_print = false; |
| if (do_print) |
| scsi_print_sense(cmd); |
| result = 0; |
| /* for passthrough, *blk_statp may be set */ |
| *blk_statp = BLK_STS_OK; |
| } |
| /* |
| * Another corner case: the SCSI status byte is non-zero but 'good'. |
| * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when |
| * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD |
| * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related |
| * intermediate statuses (both obsolete in SAM-4) as good. |
| */ |
| if (status_byte(result) && scsi_status_is_good(result)) { |
| result = 0; |
| *blk_statp = BLK_STS_OK; |
| } |
| return result; |
| } |
| |
| /* |
| * Function: scsi_io_completion() |
| * |
| * Purpose: Completion processing for block device I/O requests. |
| * |
| * Arguments: cmd - command that is finished. |
| * |
| * Lock status: Assumed that no lock is held upon entry. |
| * |
| * Returns: Nothing |
| * |
| * Notes: We will finish off the specified number of sectors. If we |
| * are done, the command block will be released and the queue |
| * function will be goosed. If we are not done then we have to |
| * figure out what to do next: |
| * |
| * a) We can call scsi_requeue_command(). The request |
| * will be unprepared and put back on the queue. Then |
| * a new command will be created for it. This should |
| * be used if we made forward progress, or if we want |
| * to switch from READ(10) to READ(6) for example. |
| * |
| * b) We can call __scsi_queue_insert(). The request will |
| * be put back on the queue and retried using the same |
| * command as before, possibly after a delay. |
| * |
| * c) We can call scsi_end_request() with blk_stat other than |
| * BLK_STS_OK, to fail the remainder of the request. |
| */ |
| void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) |
| { |
| int result = cmd->result; |
| struct request_queue *q = cmd->device->request_queue; |
| struct request *req = cmd->request; |
| blk_status_t blk_stat = BLK_STS_OK; |
| |
| if (unlikely(result)) /* a nz result may or may not be an error */ |
| result = scsi_io_completion_nz_result(cmd, result, &blk_stat); |
| |
| if (unlikely(blk_rq_is_passthrough(req))) { |
| /* |
| * scsi_result_to_blk_status may have reset the host_byte |
| */ |
| scsi_req(req)->result = cmd->result; |
| scsi_req(req)->resid_len = scsi_get_resid(cmd); |
| |
| if (unlikely(scsi_bidi_cmnd(cmd))) { |
| /* |
| * Bidi commands Must be complete as a whole, |
| * both sides at once. |
| */ |
| scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid; |
| if (scsi_end_request(req, BLK_STS_OK, blk_rq_bytes(req), |
| blk_rq_bytes(req->next_rq))) |
| WARN_ONCE(true, |
| "Bidi command with remaining bytes"); |
| return; |
| } |
| } |
| |
| /* no bidi support yet, other than in pass-through */ |
| if (unlikely(blk_bidi_rq(req))) { |
| WARN_ONCE(true, "Only support bidi command in passthrough"); |
| scmd_printk(KERN_ERR, cmd, "Killing bidi command\n"); |
| if (scsi_end_request(req, BLK_STS_IOERR, blk_rq_bytes(req), |
| blk_rq_bytes(req->next_rq))) |
| WARN_ONCE(true, "Bidi command with remaining bytes"); |
| return; |
| } |
| |
| /* |
| * Next deal with any sectors which we were able to correctly |
| * handle. |
| */ |
| SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd, |
| "%u sectors total, %d bytes done.\n", |
| blk_rq_sectors(req), good_bytes)); |
| |
| /* |
| * Next deal with any sectors which we were able to correctly |
| * handle. Failed, zero length commands always need to drop down |
| * to retry code. Fast path should return in this block. |
| */ |
| if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) { |
| if (likely(!scsi_end_request(req, blk_stat, good_bytes, 0))) |
| return; /* no bytes remaining */ |
| } |
| |
| /* Kill remainder if no retries. */ |
| if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) { |
| if (scsi_end_request(req, blk_stat, blk_rq_bytes(req), 0)) |
| WARN_ONCE(true, |
| "Bytes remaining after failed, no-retry command"); |
| return; |
| } |
| |
| /* |
| * If there had been no error, but we have leftover bytes in the |
| * requeues just queue the command up again. |
| */ |
| if (likely(result == 0)) |
| scsi_io_completion_reprep(cmd, q); |
| else |
| scsi_io_completion_action(cmd, result); |
| } |
| |
| static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb) |
| { |
| int count; |
| |
| /* |
| * If sg table allocation fails, requeue request later. |
| */ |
| if (unlikely(sg_alloc_table_chained(&sdb->table, |
| blk_rq_nr_phys_segments(req), sdb->table.sgl))) |
| return BLKPREP_DEFER; |
| |
| /* |
| * Next, walk the list, and fill in the addresses and sizes of |
| * each segment. |
| */ |
| count = blk_rq_map_sg(req->q, req, sdb->table.sgl); |
| BUG_ON(count > sdb->table.nents); |
| sdb->table.nents = count; |
| sdb->length = blk_rq_payload_bytes(req); |
| return BLKPREP_OK; |
| } |
| |
| /* |
| * Function: scsi_init_io() |
| * |
| * Purpose: SCSI I/O initialize function. |
| * |
| * Arguments: cmd - Command descriptor we wish to initialize |
| * |
| * Returns: 0 on success |
| * BLKPREP_DEFER if the failure is retryable |
| * BLKPREP_KILL if the failure is fatal |
| */ |
| int scsi_init_io(struct scsi_cmnd *cmd) |
| { |
| struct scsi_device *sdev = cmd->device; |
| struct request *rq = cmd->request; |
| bool is_mq = (rq->mq_ctx != NULL); |
| int error = BLKPREP_KILL; |
| |
| if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq))) |
| goto err_exit; |
| |
| error = scsi_init_sgtable(rq, &cmd->sdb); |
| if (error) |
| goto err_exit; |
| |
| if (blk_bidi_rq(rq)) { |
| if (!rq->q->mq_ops) { |
| struct scsi_data_buffer *bidi_sdb = |
| kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC); |
| if (!bidi_sdb) { |
| error = BLKPREP_DEFER; |
| goto err_exit; |
| } |
| |
| rq->next_rq->special = bidi_sdb; |
| } |
| |
| error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special); |
| if (error) |
| goto err_exit; |
| } |
| |
| if (blk_integrity_rq(rq)) { |
| struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; |
| int ivecs, count; |
| |
| if (prot_sdb == NULL) { |
| /* |
| * This can happen if someone (e.g. multipath) |
| * queues a command to a device on an adapter |
| * that does not support DIX. |
| */ |
| WARN_ON_ONCE(1); |
| error = BLKPREP_KILL; |
| goto err_exit; |
| } |
| |
| ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); |
| |
| if (sg_alloc_table_chained(&prot_sdb->table, ivecs, |
| prot_sdb->table.sgl)) { |
| error = BLKPREP_DEFER; |
| goto err_exit; |
| } |
| |
| count = blk_rq_map_integrity_sg(rq->q, rq->bio, |
| prot_sdb->table.sgl); |
| BUG_ON(unlikely(count > ivecs)); |
| BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q))); |
| |
| cmd->prot_sdb = prot_sdb; |
| cmd->prot_sdb->table.nents = count; |
| } |
| |
| return BLKPREP_OK; |
| err_exit: |
| if (is_mq) { |
| scsi_mq_free_sgtables(cmd); |
| } else { |
| scsi_release_buffers(cmd); |
| cmd->request->special = NULL; |
| scsi_put_command(cmd); |
| put_device(&sdev->sdev_gendev); |
| } |
| return error; |
| } |
| EXPORT_SYMBOL(scsi_init_io); |
| |
| /** |
| * scsi_initialize_rq - initialize struct scsi_cmnd partially |
| * @rq: Request associated with the SCSI command to be initialized. |
| * |
| * This function initializes the members of struct scsi_cmnd that must be |
| * initialized before request processing starts and that won't be |
| * reinitialized if a SCSI command is requeued. |
| * |
| * Called from inside blk_get_request() for pass-through requests and from |
| * inside scsi_init_command() for filesystem requests. |
| */ |
| static void scsi_initialize_rq(struct request *rq) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| |
| scsi_req_init(&cmd->req); |
| init_rcu_head(&cmd->rcu); |
| cmd->jiffies_at_alloc = jiffies; |
| cmd->retries = 0; |
| } |
| |
| /* Add a command to the list used by the aacraid and dpt_i2o drivers */ |
| void scsi_add_cmd_to_list(struct scsi_cmnd *cmd) |
| { |
| struct scsi_device *sdev = cmd->device; |
| struct Scsi_Host *shost = sdev->host; |
| unsigned long flags; |
| |
| if (shost->use_cmd_list) { |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| list_add_tail(&cmd->list, &sdev->cmd_list); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| } |
| } |
| |
| /* Remove a command from the list used by the aacraid and dpt_i2o drivers */ |
| void scsi_del_cmd_from_list(struct scsi_cmnd *cmd) |
| { |
| struct scsi_device *sdev = cmd->device; |
| struct Scsi_Host *shost = sdev->host; |
| unsigned long flags; |
| |
| if (shost->use_cmd_list) { |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| BUG_ON(list_empty(&cmd->list)); |
| list_del_init(&cmd->list); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| } |
| } |
| |
| /* Called after a request has been started. */ |
| void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) |
| { |
| void *buf = cmd->sense_buffer; |
| void *prot = cmd->prot_sdb; |
| struct request *rq = blk_mq_rq_from_pdu(cmd); |
| unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS; |
| unsigned long jiffies_at_alloc; |
| int retries; |
| |
| if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) { |
| flags |= SCMD_INITIALIZED; |
| scsi_initialize_rq(rq); |
| } |
| |
| jiffies_at_alloc = cmd->jiffies_at_alloc; |
| retries = cmd->retries; |
| /* zero out the cmd, except for the embedded scsi_request */ |
| memset((char *)cmd + sizeof(cmd->req), 0, |
| sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size); |
| |
| cmd->device = dev; |
| cmd->sense_buffer = buf; |
| cmd->prot_sdb = prot; |
| cmd->flags = flags; |
| INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); |
| cmd->jiffies_at_alloc = jiffies_at_alloc; |
| cmd->retries = retries; |
| |
| scsi_add_cmd_to_list(cmd); |
| } |
| |
| static int scsi_setup_scsi_cmnd(struct scsi_device *sdev, struct request *req) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| |
| /* |
| * Passthrough requests may transfer data, in which case they must |
| * a bio attached to them. Or they might contain a SCSI command |
| * that does not transfer data, in which case they may optionally |
| * submit a request without an attached bio. |
| */ |
| if (req->bio) { |
| int ret = scsi_init_io(cmd); |
| if (unlikely(ret)) |
| return ret; |
| } else { |
| BUG_ON(blk_rq_bytes(req)); |
| |
| memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
| } |
| |
| cmd->cmd_len = scsi_req(req)->cmd_len; |
| cmd->cmnd = scsi_req(req)->cmd; |
| cmd->transfersize = blk_rq_bytes(req); |
| cmd->allowed = scsi_req(req)->retries; |
| return BLKPREP_OK; |
| } |
| |
| /* |
| * Setup a normal block command. These are simple request from filesystems |
| * that still need to be translated to SCSI CDBs from the ULD. |
| */ |
| static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| |
| if (unlikely(sdev->handler && sdev->handler->prep_fn)) { |
| int ret = sdev->handler->prep_fn(sdev, req); |
| if (ret != BLKPREP_OK) |
| return ret; |
| } |
| |
| cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd; |
| memset(cmd->cmnd, 0, BLK_MAX_CDB); |
| return scsi_cmd_to_driver(cmd)->init_command(cmd); |
| } |
| |
| static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| |
| if (!blk_rq_bytes(req)) |
| cmd->sc_data_direction = DMA_NONE; |
| else if (rq_data_dir(req) == WRITE) |
| cmd->sc_data_direction = DMA_TO_DEVICE; |
| else |
| cmd->sc_data_direction = DMA_FROM_DEVICE; |
| |
| if (blk_rq_is_scsi(req)) |
| return scsi_setup_scsi_cmnd(sdev, req); |
| else |
| return scsi_setup_fs_cmnd(sdev, req); |
| } |
| |
| static int |
| scsi_prep_state_check(struct scsi_device *sdev, struct request *req) |
| { |
| int ret = BLKPREP_OK; |
| |
| /* |
| * If the device is not in running state we will reject some |
| * or all commands. |
| */ |
| if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { |
| switch (sdev->sdev_state) { |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| /* |
| * If the device is offline we refuse to process any |
| * commands. The device must be brought online |
| * before trying any recovery commands. |
| */ |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to offline device\n"); |
| ret = BLKPREP_KILL; |
| break; |
| case SDEV_DEL: |
| /* |
| * If the device is fully deleted, we refuse to |
| * process any commands as well. |
| */ |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to dead device\n"); |
| ret = BLKPREP_KILL; |
| break; |
| case SDEV_BLOCK: |
| case SDEV_CREATED_BLOCK: |
| ret = BLKPREP_DEFER; |
| break; |
| case SDEV_QUIESCE: |
| /* |
| * If the devices is blocked we defer normal commands. |
| */ |
| if (req && !(req->rq_flags & RQF_PREEMPT)) |
| ret = BLKPREP_DEFER; |
| break; |
| default: |
| /* |
| * For any other not fully online state we only allow |
| * special commands. In particular any user initiated |
| * command is not allowed. |
| */ |
| if (req && !(req->rq_flags & RQF_PREEMPT)) |
| ret = BLKPREP_KILL; |
| break; |
| } |
| } |
| return ret; |
| } |
| |
| static int |
| scsi_prep_return(struct request_queue *q, struct request *req, int ret) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| |
| switch (ret) { |
| case BLKPREP_KILL: |
| case BLKPREP_INVALID: |
| scsi_req(req)->result = DID_NO_CONNECT << 16; |
| /* release the command and kill it */ |
| if (req->special) { |
| struct scsi_cmnd *cmd = req->special; |
| scsi_release_buffers(cmd); |
| scsi_put_command(cmd); |
| put_device(&sdev->sdev_gendev); |
| req->special = NULL; |
| } |
| break; |
| case BLKPREP_DEFER: |
| /* |
| * If we defer, the blk_peek_request() returns NULL, but the |
| * queue must be restarted, so we schedule a callback to happen |
| * shortly. |
| */ |
| if (atomic_read(&sdev->device_busy) == 0) |
| blk_delay_queue(q, SCSI_QUEUE_DELAY); |
| break; |
| default: |
| req->rq_flags |= RQF_DONTPREP; |
| } |
| |
| return ret; |
| } |
| |
| static int scsi_prep_fn(struct request_queue *q, struct request *req) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| int ret; |
| |
| ret = scsi_prep_state_check(sdev, req); |
| if (ret != BLKPREP_OK) |
| goto out; |
| |
| if (!req->special) { |
| /* Bail if we can't get a reference to the device */ |
| if (unlikely(!get_device(&sdev->sdev_gendev))) { |
| ret = BLKPREP_DEFER; |
| goto out; |
| } |
| |
| scsi_init_command(sdev, cmd); |
| req->special = cmd; |
| } |
| |
| cmd->tag = req->tag; |
| cmd->request = req; |
| cmd->prot_op = SCSI_PROT_NORMAL; |
| |
| ret = scsi_setup_cmnd(sdev, req); |
| out: |
| return scsi_prep_return(q, req, ret); |
| } |
| |
| static void scsi_unprep_fn(struct request_queue *q, struct request *req) |
| { |
| scsi_uninit_cmd(blk_mq_rq_to_pdu(req)); |
| } |
| |
| /* |
| * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else |
| * return 0. |
| * |
| * Called with the queue_lock held. |
| */ |
| static inline int scsi_dev_queue_ready(struct request_queue *q, |
| struct scsi_device *sdev) |
| { |
| unsigned int busy; |
| |
| busy = atomic_inc_return(&sdev->device_busy) - 1; |
| if (atomic_read(&sdev->device_blocked)) { |
| if (busy) |
| goto out_dec; |
| |
| /* |
| * unblock after device_blocked iterates to zero |
| */ |
| if (atomic_dec_return(&sdev->device_blocked) > 0) { |
| /* |
| * For the MQ case we take care of this in the caller. |
| */ |
| if (!q->mq_ops) |
| blk_delay_queue(q, SCSI_QUEUE_DELAY); |
| goto out_dec; |
| } |
| SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, |
| "unblocking device at zero depth\n")); |
| } |
| |
| if (busy >= sdev->queue_depth) |
| goto out_dec; |
| |
| return 1; |
| out_dec: |
| atomic_dec(&sdev->device_busy); |
| return 0; |
| } |
| |
| /* |
| * scsi_target_queue_ready: checks if there we can send commands to target |
| * @sdev: scsi device on starget to check. |
| */ |
| static inline int scsi_target_queue_ready(struct Scsi_Host *shost, |
| struct scsi_device *sdev) |
| { |
| struct scsi_target *starget = scsi_target(sdev); |
| unsigned int busy; |
| |
| if (starget->single_lun) { |
| spin_lock_irq(shost->host_lock); |
| if (starget->starget_sdev_user && |
| starget->starget_sdev_user != sdev) { |
| spin_unlock_irq(shost->host_lock); |
| return 0; |
| } |
| starget->starget_sdev_user = sdev; |
| spin_unlock_irq(shost->host_lock); |
| } |
| |
| if (starget->can_queue <= 0) |
| return 1; |
| |
| busy = atomic_inc_return(&starget->target_busy) - 1; |
| if (atomic_read(&starget->target_blocked) > 0) { |
| if (busy) |
| goto starved; |
| |
| /* |
| * unblock after target_blocked iterates to zero |
| */ |
| if (atomic_dec_return(&starget->target_blocked) > 0) |
| goto out_dec; |
| |
| SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, |
| "unblocking target at zero depth\n")); |
| } |
| |
| if (busy >= starget->can_queue) |
| goto starved; |
| |
| return 1; |
| |
| starved: |
| spin_lock_irq(shost->host_lock); |
| list_move_tail(&sdev->starved_entry, &shost->starved_list); |
| spin_unlock_irq(shost->host_lock); |
| out_dec: |
| if (starget->can_queue > 0) |
| atomic_dec(&starget->target_busy); |
| return 0; |
| } |
| |
| /* |
| * scsi_host_queue_ready: if we can send requests to shost, return 1 else |
| * return 0. We must end up running the queue again whenever 0 is |
| * returned, else IO can hang. |
| */ |
| static inline int scsi_host_queue_ready(struct request_queue *q, |
| struct Scsi_Host *shost, |
| struct scsi_device *sdev) |
| { |
| unsigned int busy; |
| |
| if (scsi_host_in_recovery(shost)) |
| return 0; |
| |
| busy = atomic_inc_return(&shost->host_busy) - 1; |
| if (atomic_read(&shost->host_blocked) > 0) { |
| if (busy) |
| goto starved; |
| |
| /* |
| * unblock after host_blocked iterates to zero |
| */ |
| if (atomic_dec_return(&shost->host_blocked) > 0) |
| goto out_dec; |
| |
| SCSI_LOG_MLQUEUE(3, |
| shost_printk(KERN_INFO, shost, |
| "unblocking host at zero depth\n")); |
| } |
| |
| if (shost->can_queue > 0 && busy >= shost->can_queue) |
| goto starved; |
| if (shost->host_self_blocked) |
| goto starved; |
| |
| /* We're OK to process the command, so we can't be starved */ |
| if (!list_empty(&sdev->starved_entry)) { |
| spin_lock_irq(shost->host_lock); |
| if (!list_empty(&sdev->starved_entry)) |
| list_del_init(&sdev->starved_entry); |
| spin_unlock_irq(shost->host_lock); |
| } |
| |
| return 1; |
| |
| starved: |
| spin_lock_irq(shost->host_lock); |
| if (list_empty(&sdev->starved_entry)) |
| list_add_tail(&sdev->starved_entry, &shost->starved_list); |
| spin_unlock_irq(shost->host_lock); |
| out_dec: |
| scsi_dec_host_busy(shost); |
| return 0; |
| } |
| |
| /* |
| * Busy state exporting function for request stacking drivers. |
| * |
| * For efficiency, no lock is taken to check the busy state of |
| * shost/starget/sdev, since the returned value is not guaranteed and |
| * may be changed after request stacking drivers call the function, |
| * regardless of taking lock or not. |
| * |
| * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi |
| * needs to return 'not busy'. Otherwise, request stacking drivers |
| * may hold requests forever. |
| */ |
| static int scsi_lld_busy(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost; |
| |
| if (blk_queue_dying(q)) |
| return 0; |
| |
| shost = sdev->host; |
| |
| /* |
| * Ignore host/starget busy state. |
| * Since block layer does not have a concept of fairness across |
| * multiple queues, congestion of host/starget needs to be handled |
| * in SCSI layer. |
| */ |
| if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* |
| * Kill a request for a dead device |
| */ |
| static void scsi_kill_request(struct request *req, struct request_queue *q) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| struct scsi_device *sdev; |
| struct scsi_target *starget; |
| struct Scsi_Host *shost; |
| |
| blk_start_request(req); |
| |
| scmd_printk(KERN_INFO, cmd, "killing request\n"); |
| |
| sdev = cmd->device; |
| starget = scsi_target(sdev); |
| shost = sdev->host; |
| scsi_init_cmd_errh(cmd); |
| cmd->result = DID_NO_CONNECT << 16; |
| atomic_inc(&cmd->device->iorequest_cnt); |
| |
| /* |
| * SCSI request completion path will do scsi_device_unbusy(), |
| * bump busy counts. To bump the counters, we need to dance |
| * with the locks as normal issue path does. |
| */ |
| atomic_inc(&sdev->device_busy); |
| atomic_inc(&shost->host_busy); |
| if (starget->can_queue > 0) |
| atomic_inc(&starget->target_busy); |
| |
| blk_complete_request(req); |
| } |
| |
| static void scsi_softirq_done(struct request *rq) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; |
| int disposition; |
| |
| INIT_LIST_HEAD(&cmd->eh_entry); |
| |
| atomic_inc(&cmd->device->iodone_cnt); |
| if (cmd->result) |
| atomic_inc(&cmd->device->ioerr_cnt); |
| |
| disposition = scsi_decide_disposition(cmd); |
| if (disposition != SUCCESS && |
| time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { |
| sdev_printk(KERN_ERR, cmd->device, |
| "timing out command, waited %lus\n", |
| wait_for/HZ); |
| disposition = SUCCESS; |
| } |
| |
| scsi_log_completion(cmd, disposition); |
| |
| switch (disposition) { |
| case SUCCESS: |
| scsi_finish_command(cmd); |
| break; |
| case NEEDS_RETRY: |
| scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); |
| break; |
| case ADD_TO_MLQUEUE: |
| scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); |
| break; |
| default: |
| scsi_eh_scmd_add(cmd); |
| break; |
| } |
| } |
| |
| /** |
| * scsi_dispatch_command - Dispatch a command to the low-level driver. |
| * @cmd: command block we are dispatching. |
| * |
| * Return: nonzero return request was rejected and device's queue needs to be |
| * plugged. |
| */ |
| static int scsi_dispatch_cmd(struct scsi_cmnd *cmd) |
| { |
| struct Scsi_Host *host = cmd->device->host; |
| int rtn = 0; |
| |
| atomic_inc(&cmd->device->iorequest_cnt); |
| |
| /* check if the device is still usable */ |
| if (unlikely(cmd->device->sdev_state == SDEV_DEL)) { |
| /* in SDEV_DEL we error all commands. DID_NO_CONNECT |
| * returns an immediate error upwards, and signals |
| * that the device is no longer present */ |
| cmd->result = DID_NO_CONNECT << 16; |
| goto done; |
| } |
| |
| /* Check to see if the scsi lld made this device blocked. */ |
| if (unlikely(scsi_device_blocked(cmd->device))) { |
| /* |
| * in blocked state, the command is just put back on |
| * the device queue. The suspend state has already |
| * blocked the queue so future requests should not |
| * occur until the device transitions out of the |
| * suspend state. |
| */ |
| SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, |
| "queuecommand : device blocked\n")); |
| return SCSI_MLQUEUE_DEVICE_BUSY; |
| } |
| |
| /* Store the LUN value in cmnd, if needed. */ |
| if (cmd->device->lun_in_cdb) |
| cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) | |
| (cmd->device->lun << 5 & 0xe0); |
| |
| scsi_log_send(cmd); |
| |
| /* |
| * Before we queue this command, check if the command |
| * length exceeds what the host adapter can handle. |
| */ |
| if (cmd->cmd_len > cmd->device->host->max_cmd_len) { |
| SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, |
| "queuecommand : command too long. " |
| "cdb_size=%d host->max_cmd_len=%d\n", |
| cmd->cmd_len, cmd->device->host->max_cmd_len)); |
| cmd->result = (DID_ABORT << 16); |
| goto done; |
| } |
| |
| if (unlikely(host->shost_state == SHOST_DEL)) { |
| cmd->result = (DID_NO_CONNECT << 16); |
| goto done; |
| |
| } |
| |
| trace_scsi_dispatch_cmd_start(cmd); |
| rtn = host->hostt->queuecommand(host, cmd); |
| if (rtn) { |
| trace_scsi_dispatch_cmd_error(cmd, rtn); |
| if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && |
| rtn != SCSI_MLQUEUE_TARGET_BUSY) |
| rtn = SCSI_MLQUEUE_HOST_BUSY; |
| |
| SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, |
| "queuecommand : request rejected\n")); |
| } |
| |
| return rtn; |
| done: |
| cmd->scsi_done(cmd); |
| return 0; |
| } |
| |
| /** |
| * scsi_done - Invoke completion on finished SCSI command. |
| * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives |
| * ownership back to SCSI Core -- i.e. the LLDD has finished with it. |
| * |
| * Description: This function is the mid-level's (SCSI Core) interrupt routine, |
| * which regains ownership of the SCSI command (de facto) from a LLDD, and |
| * calls blk_complete_request() for further processing. |
| * |
| * This function is interrupt context safe. |
| */ |
| static void scsi_done(struct scsi_cmnd *cmd) |
| { |
| trace_scsi_dispatch_cmd_done(cmd); |
| blk_complete_request(cmd->request); |
| } |
| |
| /* |
| * Function: scsi_request_fn() |
| * |
| * Purpose: Main strategy routine for SCSI. |
| * |
| * Arguments: q - Pointer to actual queue. |
| * |
| * Returns: Nothing |
| * |
| * Lock status: request queue lock assumed to be held when called. |
| * |
| * Note: See sd_zbc.c sd_zbc_write_lock_zone() for write order |
| * protection for ZBC disks. |
| */ |
| static void scsi_request_fn(struct request_queue *q) |
| __releases(q->queue_lock) |
| __acquires(q->queue_lock) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost; |
| struct scsi_cmnd *cmd; |
| struct request *req; |
| |
| /* |
| * To start with, we keep looping until the queue is empty, or until |
| * the host is no longer able to accept any more requests. |
| */ |
| shost = sdev->host; |
| for (;;) { |
| int rtn; |
| /* |
| * get next queueable request. We do this early to make sure |
| * that the request is fully prepared even if we cannot |
| * accept it. |
| */ |
| req = blk_peek_request(q); |
| if (!req) |
| break; |
| |
| if (unlikely(!scsi_device_online(sdev))) { |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to offline device\n"); |
| scsi_kill_request(req, q); |
| continue; |
| } |
| |
| if (!scsi_dev_queue_ready(q, sdev)) |
| break; |
| |
| /* |
| * Remove the request from the request list. |
| */ |
| if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) |
| blk_start_request(req); |
| |
| spin_unlock_irq(q->queue_lock); |
| cmd = blk_mq_rq_to_pdu(req); |
| if (cmd != req->special) { |
| printk(KERN_CRIT "impossible request in %s.\n" |
| "please mail a stack trace to " |
| "linux-scsi@vger.kernel.org\n", |
| __func__); |
| blk_dump_rq_flags(req, "foo"); |
| BUG(); |
| } |
| |
| /* |
| * We hit this when the driver is using a host wide |
| * tag map. For device level tag maps the queue_depth check |
| * in the device ready fn would prevent us from trying |
| * to allocate a tag. Since the map is a shared host resource |
| * we add the dev to the starved list so it eventually gets |
| * a run when a tag is freed. |
| */ |
| if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) { |
| spin_lock_irq(shost->host_lock); |
| if (list_empty(&sdev->starved_entry)) |
| list_add_tail(&sdev->starved_entry, |
| &shost->starved_list); |
| spin_unlock_irq(shost->host_lock); |
| goto not_ready; |
| } |
| |
| if (!scsi_target_queue_ready(shost, sdev)) |
| goto not_ready; |
| |
| if (!scsi_host_queue_ready(q, shost, sdev)) |
| goto host_not_ready; |
| |
| if (sdev->simple_tags) |
| cmd->flags |= SCMD_TAGGED; |
| else |
| cmd->flags &= ~SCMD_TAGGED; |
| |
| /* |
| * Finally, initialize any error handling parameters, and set up |
| * the timers for timeouts. |
| */ |
| scsi_init_cmd_errh(cmd); |
| |
| /* |
| * Dispatch the command to the low-level driver. |
| */ |
| cmd->scsi_done = scsi_done; |
| rtn = scsi_dispatch_cmd(cmd); |
| if (rtn) { |
| scsi_queue_insert(cmd, rtn); |
| spin_lock_irq(q->queue_lock); |
| goto out_delay; |
| } |
| spin_lock_irq(q->queue_lock); |
| } |
| |
| return; |
| |
| host_not_ready: |
| if (scsi_target(sdev)->can_queue > 0) |
| atomic_dec(&scsi_target(sdev)->target_busy); |
| not_ready: |
| /* |
| * lock q, handle tag, requeue req, and decrement device_busy. We |
| * must return with queue_lock held. |
| * |
| * Decrementing device_busy without checking it is OK, as all such |
| * cases (host limits or settings) should run the queue at some |
| * later time. |
| */ |
| spin_lock_irq(q->queue_lock); |
| blk_requeue_request(q, req); |
| atomic_dec(&sdev->device_busy); |
| out_delay: |
| if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev)) |
| blk_delay_queue(q, SCSI_QUEUE_DELAY); |
| } |
| |
| static inline blk_status_t prep_to_mq(int ret) |
| { |
| switch (ret) { |
| case BLKPREP_OK: |
| return BLK_STS_OK; |
| case BLKPREP_DEFER: |
| return BLK_STS_RESOURCE; |
| default: |
| return BLK_STS_IOERR; |
| } |
| } |
| |
| /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */ |
| static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost) |
| { |
| return min_t(unsigned int, shost->sg_tablesize, SG_CHUNK_SIZE) * |
| sizeof(struct scatterlist); |
| } |
| |
| static int scsi_mq_prep_fn(struct request *req) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| struct scsi_device *sdev = req->q->queuedata; |
| struct Scsi_Host *shost = sdev->host; |
| struct scatterlist *sg; |
| |
| scsi_init_command(sdev, cmd); |
| |
| req->special = cmd; |
| |
| cmd->request = req; |
| |
| cmd->tag = req->tag; |
| cmd->prot_op = SCSI_PROT_NORMAL; |
| |
| sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; |
| cmd->sdb.table.sgl = sg; |
| |
| if (scsi_host_get_prot(shost)) { |
| memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); |
| |
| cmd->prot_sdb->table.sgl = |
| (struct scatterlist *)(cmd->prot_sdb + 1); |
| } |
| |
| if (blk_bidi_rq(req)) { |
| struct request *next_rq = req->next_rq; |
| struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq); |
| |
| memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer)); |
| bidi_sdb->table.sgl = |
| (struct scatterlist *)(bidi_sdb + 1); |
| |
| next_rq->special = bidi_sdb; |
| } |
| |
| blk_mq_start_request(req); |
| |
| return scsi_setup_cmnd(sdev, req); |
| } |
| |
| static void scsi_mq_done(struct scsi_cmnd *cmd) |
| { |
| trace_scsi_dispatch_cmd_done(cmd); |
| blk_mq_complete_request(cmd->request); |
| } |
| |
| static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx) |
| { |
| struct request_queue *q = hctx->queue; |
| struct scsi_device *sdev = q->queuedata; |
| |
| atomic_dec(&sdev->device_busy); |
| put_device(&sdev->sdev_gendev); |
| } |
| |
| static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx) |
| { |
| struct request_queue *q = hctx->queue; |
| struct scsi_device *sdev = q->queuedata; |
| |
| if (!get_device(&sdev->sdev_gendev)) |
| goto out; |
| if (!scsi_dev_queue_ready(q, sdev)) |
| goto out_put_device; |
| |
| return true; |
| |
| out_put_device: |
| put_device(&sdev->sdev_gendev); |
| out: |
| if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev)) |
| blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY); |
| return false; |
| } |
| |
| static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, |
| const struct blk_mq_queue_data *bd) |
| { |
| struct request *req = bd->rq; |
| struct request_queue *q = req->q; |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost = sdev->host; |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| blk_status_t ret; |
| int reason; |
| |
| ret = prep_to_mq(scsi_prep_state_check(sdev, req)); |
| if (ret != BLK_STS_OK) |
| goto out_put_budget; |
| |
| ret = BLK_STS_RESOURCE; |
| if (!scsi_target_queue_ready(shost, sdev)) |
| goto out_put_budget; |
| if (!scsi_host_queue_ready(q, shost, sdev)) |
| goto out_dec_target_busy; |
| |
| if (!(req->rq_flags & RQF_DONTPREP)) { |
| ret = prep_to_mq(scsi_mq_prep_fn(req)); |
| if (ret != BLK_STS_OK) |
| goto out_dec_host_busy; |
| req->rq_flags |= RQF_DONTPREP; |
| } else { |
| blk_mq_start_request(req); |
| } |
| |
| if (sdev->simple_tags) |
| cmd->flags |= SCMD_TAGGED; |
| else |
| cmd->flags &= ~SCMD_TAGGED; |
| |
| scsi_init_cmd_errh(cmd); |
| cmd->scsi_done = scsi_mq_done; |
| |
| reason = scsi_dispatch_cmd(cmd); |
| if (reason) { |
| scsi_set_blocked(cmd, reason); |
| ret = BLK_STS_RESOURCE; |
| goto out_dec_host_busy; |
| } |
| |
| return BLK_STS_OK; |
| |
| out_dec_host_busy: |
| scsi_dec_host_busy(shost); |
| out_dec_target_busy: |
| if (scsi_target(sdev)->can_queue > 0) |
| atomic_dec(&scsi_target(sdev)->target_busy); |
| out_put_budget: |
| scsi_mq_put_budget(hctx); |
| switch (ret) { |
| case BLK_STS_OK: |
| break; |
| case BLK_STS_RESOURCE: |
| if (atomic_read(&sdev->device_busy) || |
| scsi_device_blocked(sdev)) |
| ret = BLK_STS_DEV_RESOURCE; |
| break; |
| default: |
| /* |
| * Make sure to release all allocated ressources when |
| * we hit an error, as we will never see this command |
| * again. |
| */ |
| if (req->rq_flags & RQF_DONTPREP) |
| scsi_mq_uninit_cmd(cmd); |
| break; |
| } |
| return ret; |
| } |
| |
| static enum blk_eh_timer_return scsi_timeout(struct request *req, |
| bool reserved) |
| { |
| if (reserved) |
| return BLK_EH_RESET_TIMER; |
| return scsi_times_out(req); |
| } |
| |
| static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, |
| unsigned int hctx_idx, unsigned int numa_node) |
| { |
| struct Scsi_Host *shost = set->driver_data; |
| const bool unchecked_isa_dma = shost->unchecked_isa_dma; |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| struct scatterlist *sg; |
| |
| if (unchecked_isa_dma) |
| cmd->flags |= SCMD_UNCHECKED_ISA_DMA; |
| cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, |
| GFP_KERNEL, numa_node); |
| if (!cmd->sense_buffer) |
| return -ENOMEM; |
| cmd->req.sense = cmd->sense_buffer; |
| |
| if (scsi_host_get_prot(shost)) { |
| sg = (void *)cmd + sizeof(struct scsi_cmnd) + |
| shost->hostt->cmd_size; |
| cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost); |
| } |
| |
| return 0; |
| } |
| |
| static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq, |
| unsigned int hctx_idx) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| |
| scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA, |
| cmd->sense_buffer); |
| } |
| |
| static int scsi_map_queues(struct blk_mq_tag_set *set) |
| { |
| struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set); |
| |
| if (shost->hostt->map_queues) |
| return shost->hostt->map_queues(shost); |
| return blk_mq_map_queues(set); |
| } |
| |
| void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) |
| { |
| struct device *dev = shost->dma_dev; |
| |
| /* |
| * this limit is imposed by hardware restrictions |
| */ |
| blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, |
| SG_MAX_SEGMENTS)); |
| |
| if (scsi_host_prot_dma(shost)) { |
| shost->sg_prot_tablesize = |
| min_not_zero(shost->sg_prot_tablesize, |
| (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); |
| BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); |
| blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); |
| } |
| |
| blk_queue_max_hw_sectors(q, shost->max_sectors); |
| if (shost->unchecked_isa_dma) |
| blk_queue_bounce_limit(q, BLK_BOUNCE_ISA); |
| blk_queue_segment_boundary(q, shost->dma_boundary); |
| dma_set_seg_boundary(dev, shost->dma_boundary); |
| |
| blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); |
| |
| if (!shost->use_clustering) |
| q->limits.cluster = 0; |
| |
| /* |
| * Set a reasonable default alignment: The larger of 32-byte (dword), |
| * which is a common minimum for HBAs, and the minimum DMA alignment, |
| * which is set by the platform. |
| * |
| * Devices that require a bigger alignment can increase it later. |
| */ |
| blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); |
| } |
| EXPORT_SYMBOL_GPL(__scsi_init_queue); |
| |
| static int scsi_old_init_rq(struct request_queue *q, struct request *rq, |
| gfp_t gfp) |
| { |
| struct Scsi_Host *shost = q->rq_alloc_data; |
| const bool unchecked_isa_dma = shost->unchecked_isa_dma; |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| |
| memset(cmd, 0, sizeof(*cmd)); |
| |
| if (unchecked_isa_dma) |
| cmd->flags |= SCMD_UNCHECKED_ISA_DMA; |
| cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, gfp, |
| NUMA_NO_NODE); |
| if (!cmd->sense_buffer) |
| goto fail; |
| cmd->req.sense = cmd->sense_buffer; |
| |
| if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) { |
| cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp); |
| if (!cmd->prot_sdb) |
| goto fail_free_sense; |
| } |
| |
| return 0; |
| |
| fail_free_sense: |
| scsi_free_sense_buffer(unchecked_isa_dma, cmd->sense_buffer); |
| fail: |
| return -ENOMEM; |
| } |
| |
| static void scsi_old_exit_rq(struct request_queue *q, struct request *rq) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| |
| if (cmd->prot_sdb) |
| kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb); |
| scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA, |
| cmd->sense_buffer); |
| } |
| |
| struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev) |
| { |
| struct Scsi_Host *shost = sdev->host; |
| struct request_queue *q; |
| |
| q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE, NULL); |
| if (!q) |
| return NULL; |
| q->cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; |
| q->rq_alloc_data = shost; |
| q->request_fn = scsi_request_fn; |
| q->init_rq_fn = scsi_old_init_rq; |
| q->exit_rq_fn = scsi_old_exit_rq; |
| q->initialize_rq_fn = scsi_initialize_rq; |
| |
| if (blk_init_allocated_queue(q) < 0) { |
| blk_cleanup_queue(q); |
| return NULL; |
| } |
| |
| __scsi_init_queue(shost, q); |
| blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, q); |
| blk_queue_prep_rq(q, scsi_prep_fn); |
| blk_queue_unprep_rq(q, scsi_unprep_fn); |
| blk_queue_softirq_done(q, scsi_softirq_done); |
| blk_queue_rq_timed_out(q, scsi_times_out); |
| blk_queue_lld_busy(q, scsi_lld_busy); |
| return q; |
| } |
| |
| static const struct blk_mq_ops scsi_mq_ops = { |
| .get_budget = scsi_mq_get_budget, |
| .put_budget = scsi_mq_put_budget, |
| .queue_rq = scsi_queue_rq, |
| .complete = scsi_softirq_done, |
| .timeout = scsi_timeout, |
| #ifdef CONFIG_BLK_DEBUG_FS |
| .show_rq = scsi_show_rq, |
| #endif |
| .init_request = scsi_mq_init_request, |
| .exit_request = scsi_mq_exit_request, |
| .initialize_rq_fn = scsi_initialize_rq, |
| .map_queues = scsi_map_queues, |
| }; |
| |
| struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev) |
| { |
| sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set); |
| if (IS_ERR(sdev->request_queue)) |
| return NULL; |
| |
| sdev->request_queue->queuedata = sdev; |
| __scsi_init_queue(sdev->host, sdev->request_queue); |
| blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue); |
| return sdev->request_queue; |
| } |
| |
| int scsi_mq_setup_tags(struct Scsi_Host *shost) |
| { |
| unsigned int cmd_size, sgl_size; |
| |
| sgl_size = scsi_mq_sgl_size(shost); |
| cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size; |
| if (scsi_host_get_prot(shost)) |
| cmd_size += sizeof(struct scsi_data_buffer) + sgl_size; |
| |
| memset(&shost->tag_set, 0, sizeof(shost->tag_set)); |
| shost->tag_set.ops = &scsi_mq_ops; |
| shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1; |
| shost->tag_set.queue_depth = shost->can_queue; |
| shost->tag_set.cmd_size = cmd_size; |
| shost->tag_set.numa_node = NUMA_NO_NODE; |
| shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; |
| shost->tag_set.flags |= |
| BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy); |
| shost->tag_set.driver_data = shost; |
| |
| return blk_mq_alloc_tag_set(&shost->tag_set); |
| } |
| |
| void scsi_mq_destroy_tags(struct Scsi_Host *shost) |
| { |
| blk_mq_free_tag_set(&shost->tag_set); |
| } |
| |
| /** |
| * scsi_device_from_queue - return sdev associated with a request_queue |
| * @q: The request queue to return the sdev from |
| * |
| * Return the sdev associated with a request queue or NULL if the |
| * request_queue does not reference a SCSI device. |
| */ |
| struct scsi_device *scsi_device_from_queue(struct request_queue *q) |
| { |
| struct scsi_device *sdev = NULL; |
| |
| if (q->mq_ops) { |
| if (q->mq_ops == &scsi_mq_ops) |
| sdev = q->queuedata; |
| } else if (q->request_fn == scsi_request_fn) |
| sdev = q->queuedata; |
| if (!sdev || !get_device(&sdev->sdev_gendev)) |
| sdev = NULL; |
| |
| return sdev; |
| } |
| EXPORT_SYMBOL_GPL(scsi_device_from_queue); |
| |
| /* |
| * Function: scsi_block_requests() |
| * |
| * Purpose: Utility function used by low-level drivers to prevent further |
| * commands from being queued to the device. |
| * |
| * Arguments: shost - Host in question |
| * |
| * Returns: Nothing |
| * |
| * Lock status: No locks are assumed held. |
| * |
| * Notes: There is no timer nor any other means by which the requests |
| * get unblocked other than the low-level driver calling |
| * scsi_unblock_requests(). |
| */ |
| void scsi_block_requests(struct Scsi_Host *shost) |
| { |
| shost->host_self_blocked = 1; |
| } |
| EXPORT_SYMBOL(scsi_block_requests); |
| |
| /* |
| * Function: scsi_unblock_requests() |
| * |
| * Purpose: Utility function used by low-level drivers to allow further |
| * commands from being queued to the device. |
| * |
| * Arguments: shost - Host in question |
| * |
| * Returns: Nothing |
| * |
| * Lock status: No locks are assumed held. |
| * |
| * Notes: There is no timer nor any other means by which the requests |
| * get unblocked other than the low-level driver calling |
| * scsi_unblock_requests(). |
| * |
| * This is done as an API function so that changes to the |
| * internals of the scsi mid-layer won't require wholesale |
| * changes to drivers that use this feature. |
| */ |
| void scsi_unblock_requests(struct Scsi_Host *shost) |
| { |
| shost->host_self_blocked = 0; |
| scsi_run_host_queues(shost); |
| } |
| EXPORT_SYMBOL(scsi_unblock_requests); |
| |
| int __init scsi_init_queue(void) |
| { |
| scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", |
| sizeof(struct scsi_data_buffer), |
| 0, 0, NULL); |
| if (!scsi_sdb_cache) { |
| printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| void scsi_exit_queue(void) |
| { |
| kmem_cache_destroy(scsi_sense_cache); |
| kmem_cache_destroy(scsi_sense_isadma_cache); |
| kmem_cache_destroy(scsi_sdb_cache); |
| } |
| |
| /** |
| * scsi_mode_select - issue a mode select |
| * @sdev: SCSI device to be queried |
| * @pf: Page format bit (1 == standard, 0 == vendor specific) |
| * @sp: Save page bit (0 == don't save, 1 == save) |
| * @modepage: mode page being requested |
| * @buffer: request buffer (may not be smaller than eight bytes) |
| * @len: length of request buffer. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @data: returns a structure abstracting the mode header data |
| * @sshdr: place to put sense data (or NULL if no sense to be collected). |
| * must be SCSI_SENSE_BUFFERSIZE big. |
| * |
| * Returns zero if successful; negative error number or scsi |
| * status on error |
| * |
| */ |
| int |
| scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, |
| unsigned char *buffer, int len, int timeout, int retries, |
| struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
| { |
| unsigned char cmd[10]; |
| unsigned char *real_buffer; |
| int ret; |
| |
| memset(cmd, 0, sizeof(cmd)); |
| cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); |
| |
| if (sdev->use_10_for_ms) { |
| if (len > 65535) |
| return -EINVAL; |
| real_buffer = kmalloc(8 + len, GFP_KERNEL); |
| if (!real_buffer) |
| return -ENOMEM; |
| memcpy(real_buffer + 8, buffer, len); |
| len += 8; |
| real_buffer[0] = 0; |
| real_buffer[1] = 0; |
| real_buffer[2] = data->medium_type; |
| real_buffer[3] = data->device_specific; |
| real_buffer[4] = data->longlba ? 0x01 : 0; |
| real_buffer[5] = 0; |
| real_buffer[6] = data->block_descriptor_length >> 8; |
| real_buffer[7] = data->block_descriptor_length; |
| |
| cmd[0] = MODE_SELECT_10; |
| cmd[7] = len >> 8; |
| cmd[8] = len; |
| } else { |
| if (len > 255 || data->block_descriptor_length > 255 || |
| data->longlba) |
| return -EINVAL; |
| |
| real_buffer = kmalloc(4 + len, GFP_KERNEL); |
| if (!real_buffer) |
| return -ENOMEM; |
| memcpy(real_buffer + 4, buffer, len); |
| len += 4; |
| real_buffer[0] = 0; |
| real_buffer[1] = data->medium_type; |
| real_buffer[2] = data->device_specific; |
| real_buffer[3] = data->block_descriptor_length; |
| |
| |
| cmd[0] = MODE_SELECT; |
| cmd[4] = len; |
| } |
| |
| ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, |
| sshdr, timeout, retries, NULL); |
| kfree(real_buffer); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(scsi_mode_select); |
| |
| /** |
| * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. |
| * @sdev: SCSI device to be queried |
| * @dbd: set if mode sense will allow block descriptors to be returned |
| * @modepage: mode page being requested |
| * @buffer: request buffer (may not be smaller than eight bytes) |
| * @len: length of request buffer. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @data: returns a structure abstracting the mode header data |
| * @sshdr: place to put sense data (or NULL if no sense to be collected). |
| * must be SCSI_SENSE_BUFFERSIZE big. |
| * |
| * Returns zero if unsuccessful, or the header offset (either 4 |
| * or 8 depending on whether a six or ten byte command was |
| * issued) if successful. |
| */ |
| int |
| scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
| unsigned char *buffer, int len, int timeout, int retries, |
| struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
| { |
| unsigned char cmd[12]; |
| int use_10_for_ms; |
| int header_length; |
| int result, retry_count = retries; |
| struct scsi_sense_hdr my_sshdr; |
| |
| memset(data, 0, sizeof(*data)); |
| memset(&cmd[0], 0, 12); |
| cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ |
| cmd[2] = modepage; |
| |
| /* caller might not be interested in sense, but we need it */ |
| if (!sshdr) |
| sshdr = &my_sshdr; |
| |
| retry: |
| use_10_for_ms = sdev->use_10_for_ms; |
| |
| if (use_10_for_ms) { |
| if (len < 8) |
| len = 8; |
| |
| cmd[0] = MODE_SENSE_10; |
| cmd[8] = len; |
| header_length = 8; |
| } else { |
| if (len < 4) |
| len = 4; |
| |
| cmd[0] = MODE_SENSE; |
| cmd[4] = len; |
| header_length = 4; |
| } |
| |
| memset(buffer, 0, len); |
| |
| result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
| sshdr, timeout, retries, NULL); |
| |
| /* This code looks awful: what it's doing is making sure an |
| * ILLEGAL REQUEST sense return identifies the actual command |
| * byte as the problem. MODE_SENSE commands can return |
| * ILLEGAL REQUEST if the code page isn't supported */ |
| |
| if (use_10_for_ms && !scsi_status_is_good(result) && |
| driver_byte(result) == DRIVER_SENSE) { |
| if (scsi_sense_valid(sshdr)) { |
| if ((sshdr->sense_key == ILLEGAL_REQUEST) && |
| (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { |
| /* |
| * Invalid command operation code |
| */ |
| sdev->use_10_for_ms = 0; |
| goto retry; |
| } |
| } |
| } |
| |
| if(scsi_status_is_good(result)) { |
| if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
| (modepage == 6 || modepage == 8))) { |
| /* Initio breakage? */ |
| header_length = 0; |
| data->length = 13; |
| data->medium_type = 0; |
| data->device_specific = 0; |
| data->longlba = 0; |
| data->block_descriptor_length = 0; |
| } else if(use_10_for_ms) { |
| data->length = buffer[0]*256 + buffer[1] + 2; |
| data->medium_type = buffer[2]; |
| data->device_specific = buffer[3]; |
| data->longlba = buffer[4] & 0x01; |
| data->block_descriptor_length = buffer[6]*256 |
| + buffer[7]; |
| } else { |
| data->length = buffer[0] + 1; |
| data->medium_type = buffer[1]; |
| data->device_specific = buffer[2]; |
| data->block_descriptor_length = buffer[3]; |
| } |
| data->header_length = header_length; |
| } else if ((status_byte(result) == CHECK_CONDITION) && |
| scsi_sense_valid(sshdr) && |
| sshdr->sense_key == UNIT_ATTENTION && retry_count) { |
| retry_count--; |
| goto retry; |
| } |
| |
| return result; |
| } |
| EXPORT_SYMBOL(scsi_mode_sense); |
| |
| /** |
| * scsi_test_unit_ready - test if unit is ready |
| * @sdev: scsi device to change the state of. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @sshdr: outpout pointer for decoded sense information. |
| * |
| * Returns zero if unsuccessful or an error if TUR failed. For |
| * removable media, UNIT_ATTENTION sets ->changed flag. |
| **/ |
| int |
| scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, |
| struct scsi_sense_hdr *sshdr) |
| { |
| char cmd[] = { |
| TEST_UNIT_READY, 0, 0, 0, 0, 0, |
| }; |
| int result; |
| |
| /* try to eat the UNIT_ATTENTION if there are enough retries */ |
| do { |
| result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, |
| timeout, 1, NULL); |
| if (sdev->removable && scsi_sense_valid(sshdr) && |
| sshdr->sense_key == UNIT_ATTENTION) |
| sdev->changed = 1; |
| } while (scsi_sense_valid(sshdr) && |
| sshdr->sense_key == UNIT_ATTENTION && --retries); |
| |
| return result; |
| } |
| EXPORT_SYMBOL(scsi_test_unit_ready); |
| |
| /** |
| * scsi_device_set_state - Take the given device through the device state model. |
| * @sdev: scsi device to change the state of. |
| * @state: state to change to. |
| * |
| * Returns zero if successful or an error if the requested |
| * transition is illegal. |
| */ |
| int |
| scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) |
| { |
| enum scsi_device_state oldstate = sdev->sdev_state; |
| |
| if (state == oldstate) |
| return 0; |
| |
| switch (state) { |
| case SDEV_CREATED: |
| switch (oldstate) { |
| case SDEV_CREATED_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_RUNNING: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| case SDEV_QUIESCE: |
| case SDEV_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_QUIESCE: |
| switch (oldstate) { |
| case SDEV_RUNNING: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_QUIESCE: |
| case SDEV_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_BLOCK: |
| switch (oldstate) { |
| case SDEV_RUNNING: |
| case SDEV_CREATED_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_CREATED_BLOCK: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_CANCEL: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_QUIESCE: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_DEL: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| case SDEV_CANCEL: |
| case SDEV_BLOCK: |
| case SDEV_CREATED_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| } |
| sdev->sdev_state = state; |
| return 0; |
| |
| illegal: |
| SCSI_LOG_ERROR_RECOVERY(1, |
| sdev_printk(KERN_ERR, sdev, |
| "Illegal state transition %s->%s", |
| scsi_device_state_name(oldstate), |
| scsi_device_state_name(state)) |
| ); |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(scsi_device_set_state); |
| |
| /** |
| * sdev_evt_emit - emit a single SCSI device uevent |
| * @sdev: associated SCSI device |
| * @evt: event to emit |
| * |
| * Send a single uevent (scsi_event) to the associated scsi_device. |
| */ |
| static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) |
| { |
| int idx = 0; |
| char *envp[3]; |
| |
| switch (evt->evt_type) { |
| case SDEV_EVT_MEDIA_CHANGE: |
| envp[idx++] = "SDEV_MEDIA_CHANGE=1"; |
| break; |
| case SDEV_EVT_INQUIRY_CHANGE_REPORTED: |
| scsi_rescan_device(&sdev->sdev_gendev); |
| envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED"; |
| break; |
| case SDEV_EVT_CAPACITY_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED"; |
| break; |
| case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: |
| envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED"; |
| break; |
| case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED"; |
| break; |
| case SDEV_EVT_LUN_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED"; |
| break; |
| case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED"; |
| break; |
| case SDEV_EVT_POWER_ON_RESET_OCCURRED: |
| envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED"; |
| break; |
| default: |
| /* do nothing */ |
| break; |
| } |
| |
| envp[idx++] = NULL; |
| |
| kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); |
| } |
| |
| /** |
| * sdev_evt_thread - send a uevent for each scsi event |
| * @work: work struct for scsi_device |
| * |
| * Dispatch queued events to their associated scsi_device kobjects |
| * as uevents. |
| */ |
| void scsi_evt_thread(struct work_struct *work) |
| { |
| struct scsi_device *sdev; |
| enum scsi_device_event evt_type; |
| LIST_HEAD(event_list); |
| |
| sdev = container_of(work, struct scsi_device, event_work); |
| |
| for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++) |
| if (test_and_clear_bit(evt_type, sdev->pending_events)) |
| sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL); |
| |
| while (1) { |
| struct scsi_event *evt; |
| struct list_head *this, *tmp; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| list_splice_init(&sdev->event_list, &event_list); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| |
| if (list_empty(&event_list)) |
| break; |
| |
| list_for_each_safe(this, tmp, &event_list) { |
| evt = list_entry(this, struct scsi_event, node); |
| list_del(&evt->node); |
| scsi_evt_emit(sdev, evt); |
| kfree(evt); |
| } |
| } |
| } |
| |
| /** |
| * sdev_evt_send - send asserted event to uevent thread |
| * @sdev: scsi_device event occurred on |
| * @evt: event to send |
| * |
| * Assert scsi device event asynchronously. |
| */ |
| void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) |
| { |
| unsigned long flags; |
| |
| #if 0 |
| /* FIXME: currently this check eliminates all media change events |
| * for polled devices. Need to update to discriminate between AN |
| * and polled events */ |
| if (!test_bit(evt->evt_type, sdev->supported_events)) { |
| kfree(evt); |
| return; |
| } |
| #endif |
| |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| list_add_tail(&evt->node, &sdev->event_list); |
| schedule_work(&sdev->event_work); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_send); |
| |
| /** |
| * sdev_evt_alloc - allocate a new scsi event |
| * @evt_type: type of event to allocate |
| * @gfpflags: GFP flags for allocation |
| * |
| * Allocates and returns a new scsi_event. |
| */ |
| struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, |
| gfp_t gfpflags) |
| { |
| struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); |
| if (!evt) |
| return NULL; |
| |
| evt->evt_type = evt_type; |
| INIT_LIST_HEAD(&evt->node); |
| |
| /* evt_type-specific initialization, if any */ |
| switch (evt_type) { |
| case SDEV_EVT_MEDIA_CHANGE: |
| case SDEV_EVT_INQUIRY_CHANGE_REPORTED: |
| case SDEV_EVT_CAPACITY_CHANGE_REPORTED: |
| case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: |
| case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: |
| case SDEV_EVT_LUN_CHANGE_REPORTED: |
| case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: |
| case SDEV_EVT_POWER_ON_RESET_OCCURRED: |
| default: |
| /* do nothing */ |
| break; |
| } |
| |
| return evt; |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_alloc); |
| |
| /** |
| * sdev_evt_send_simple - send asserted event to uevent thread |
| * @sdev: scsi_device event occurred on |
| * @evt_type: type of event to send |
| * @gfpflags: GFP flags for allocation |
| * |
| * Assert scsi device event asynchronously, given an event type. |
| */ |
| void sdev_evt_send_simple(struct scsi_device *sdev, |
| enum scsi_device_event evt_type, gfp_t gfpflags) |
| { |
| struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); |
| if (!evt) { |
| sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", |
| evt_type); |
| return; |
| } |
| |
| sdev_evt_send(sdev, evt); |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_send_simple); |
| |
| /** |
| * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn() |
| * @sdev: SCSI device to count the number of scsi_request_fn() callers for. |
| */ |
| static int scsi_request_fn_active(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| int request_fn_active; |
| |
| WARN_ON_ONCE(sdev->host->use_blk_mq); |
| |
| spin_lock_irq(q->queue_lock); |
| request_fn_active = q->request_fn_active; |
| spin_unlock_irq(q->queue_lock); |
| |
| return request_fn_active; |
| } |
| |
| /** |
| * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls |
| * @sdev: SCSI device pointer. |
| * |
| * Wait until the ongoing shost->hostt->queuecommand() calls that are |
| * invoked from scsi_request_fn() have finished. |
| */ |
| static void scsi_wait_for_queuecommand(struct scsi_device *sdev) |
| { |
| WARN_ON_ONCE(sdev->host->use_blk_mq); |
| |
| while (scsi_request_fn_active(sdev)) |
| msleep(20); |
| } |
| |
| /** |
| * scsi_device_quiesce - Block user issued commands. |
| * @sdev: scsi device to quiesce. |
| * |
| * This works by trying to transition to the SDEV_QUIESCE state |
| * (which must be a legal transition). When the device is in this |
| * state, only special requests will be accepted, all others will |
| * be deferred. Since special requests may also be requeued requests, |
| * a successful return doesn't guarantee the device will be |
| * totally quiescent. |
| * |
| * Must be called with user context, may sleep. |
| * |
| * Returns zero if unsuccessful or an error if not. |
| */ |
| int |
| scsi_device_quiesce(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| int err; |
| |
| /* |
| * It is allowed to call scsi_device_quiesce() multiple times from |
| * the same context but concurrent scsi_device_quiesce() calls are |
| * not allowed. |
| */ |
| WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current); |
| |
| blk_set_preempt_only(q); |
| |
| blk_mq_freeze_queue(q); |
| /* |
| * Ensure that the effect of blk_set_preempt_only() will be visible |
| * for percpu_ref_tryget() callers that occur after the queue |
| * unfreeze even if the queue was already frozen before this function |
| * was called. See also https://lwn.net/Articles/573497/. |
| */ |
| synchronize_rcu(); |
| blk_mq_unfreeze_queue(q); |
| |
| mutex_lock(&sdev->state_mutex); |
| err = scsi_device_set_state(sdev, SDEV_QUIESCE); |
| if (err == 0) |
| sdev->quiesced_by = current; |
| else |
| blk_clear_preempt_only(q); |
| mutex_unlock(&sdev->state_mutex); |
| |
| return err; |
| } |
| EXPORT_SYMBOL(scsi_device_quiesce); |
| |
| /** |
| * scsi_device_resume - Restart user issued commands to a quiesced device. |
| * @sdev: scsi device to resume. |
| * |
| * Moves the device from quiesced back to running and restarts the |
| * queues. |
| * |
| * Must be called with user context, may sleep. |
| */ |
| void scsi_device_resume(struct scsi_device *sdev) |
| { |
| /* check if the device state was mutated prior to resume, and if |
| * so assume the state is being managed elsewhere (for example |
| * device deleted during suspend) |
| */ |
| mutex_lock(&sdev->state_mutex); |
| WARN_ON_ONCE(!sdev->quiesced_by); |
| sdev->quiesced_by = NULL; |
| blk_clear_preempt_only(sdev->request_queue); |
| if (sdev->sdev_state == SDEV_QUIESCE) |
| scsi_device_set_state(sdev, SDEV_RUNNING); |
| mutex_unlock(&sdev->state_mutex); |
| } |
| EXPORT_SYMBOL(scsi_device_resume); |
| |
| static void |
| device_quiesce_fn(struct scsi_device *sdev, void *data) |
| { |
| scsi_device_quiesce(sdev); |
| } |
| |
| void |
| scsi_target_quiesce(struct scsi_target *starget) |
| { |
| starget_for_each_device(starget, NULL, device_quiesce_fn); |
| } |
| EXPORT_SYMBOL(scsi_target_quiesce); |
| |
| static void |
| device_resume_fn(struct scsi_device *sdev, void *data) |
| { |
| scsi_device_resume(sdev); |
| } |
| |
| void |
| scsi_target_resume(struct scsi_target *starget) |
| { |
| starget_for_each_device(starget, NULL, device_resume_fn); |
| } |
| EXPORT_SYMBOL(scsi_target_resume); |
| |
| /** |
| * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state |
| * @sdev: device to block |
| * |
| * Pause SCSI command processing on the specified device. Does not sleep. |
| * |
| * Returns zero if successful or a negative error code upon failure. |
| * |
| * Notes: |
| * This routine transitions the device to the SDEV_BLOCK state (which must be |
| * a legal transition). When the device is in this state, command processing |
| * is paused until the device leaves the SDEV_BLOCK state. See also |
| * scsi_internal_device_unblock_nowait(). |
| */ |
| int scsi_internal_device_block_nowait(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| unsigned long flags; |
| int err = 0; |
| |
| err = scsi_device_set_state(sdev, SDEV_BLOCK); |
| if (err) { |
| err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); |
| |
| if (err) |
| return err; |
| } |
| |
| /* |
| * The device has transitioned to SDEV_BLOCK. Stop the |
| * block layer from calling the midlayer with this device's |
| * request queue. |
| */ |
| if (q->mq_ops) { |
| blk_mq_quiesce_queue_nowait(q); |
| } else { |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_stop_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); |
| |
| /** |
| * scsi_internal_device_block - try to transition to the SDEV_BLOCK state |
| * @sdev: device to block |
| * |
| * Pause SCSI command processing on the specified device and wait until all |
| * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep. |
| * |
| * Returns zero if successful or a negative error code upon failure. |
| * |
| * Note: |
| * This routine transitions the device to the SDEV_BLOCK state (which must be |
| * a legal transition). When the device is in this state, command processing |
| * is paused until the device leaves the SDEV_BLOCK state. See also |
| * scsi_internal_device_unblock(). |
| * |
| * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after |
| * scsi_internal_device_block() has blocked a SCSI device and also |
| * remove the rport mutex lock and unlock calls from srp_queuecommand(). |
| */ |
| static int scsi_internal_device_block(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| int err; |
| |
| mutex_lock(&sdev->state_mutex); |
| err = scsi_internal_device_block_nowait(sdev); |
| if (err == 0) { |
| if (q->mq_ops) |
| blk_mq_quiesce_queue(q); |
| else |
| scsi_wait_for_queuecommand(sdev); |
| } |
| mutex_unlock(&sdev->state_mutex); |
| |
| return err; |
| } |
| |
| void scsi_start_queue(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| unsigned long flags; |
| |
| if (q->mq_ops) { |
| blk_mq_unquiesce_queue(q); |
| } else { |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_start_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| } |
| |
| /** |
| * scsi_internal_device_unblock_nowait - resume a device after a block request |
| * @sdev: device to resume |
| * @new_state: state to set the device to after unblocking |
| * |
| * Restart the device queue for a previously suspended SCSI device. Does not |
| * sleep. |
| * |
| * Returns zero if successful or a negative error code upon failure. |
| * |
| * Notes: |
| * This routine transitions the device to the SDEV_RUNNING state or to one of |
| * the offline states (which must be a legal transition) allowing the midlayer |
| * to goose the queue for this device. |
| */ |
| int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, |
| enum scsi_device_state new_state) |
| { |
| /* |
| * Try to transition the scsi device to SDEV_RUNNING or one of the |
| * offlined states and goose the device queue if successful. |
| */ |
| switch (sdev->sdev_state) { |
| case SDEV_BLOCK: |
| case SDEV_TRANSPORT_OFFLINE: |
| sdev->sdev_state = new_state; |
| break; |
| case SDEV_CREATED_BLOCK: |
| |