| /* |
| * bsg.c - block layer implementation of the sg v4 interface |
| * |
| * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs |
| * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com> |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License version 2. See the file "COPYING" in the main directory of this |
| * archive for more details. |
| * |
| */ |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/file.h> |
| #include <linux/blkdev.h> |
| #include <linux/cdev.h> |
| #include <linux/jiffies.h> |
| #include <linux/percpu.h> |
| #include <linux/idr.h> |
| #include <linux/bsg.h> |
| #include <linux/slab.h> |
| |
| #include <scsi/scsi.h> |
| #include <scsi/scsi_ioctl.h> |
| #include <scsi/scsi_cmnd.h> |
| #include <scsi/scsi_device.h> |
| #include <scsi/scsi_driver.h> |
| #include <scsi/sg.h> |
| |
| #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" |
| #define BSG_VERSION "0.4" |
| |
| #define bsg_dbg(bd, fmt, ...) \ |
| pr_debug("%s: " fmt, (bd)->name, ##__VA_ARGS__) |
| |
| struct bsg_device { |
| struct request_queue *queue; |
| spinlock_t lock; |
| struct hlist_node dev_list; |
| refcount_t ref_count; |
| char name[20]; |
| int max_queue; |
| }; |
| |
| #define BSG_DEFAULT_CMDS 64 |
| #define BSG_MAX_DEVS 32768 |
| |
| static DEFINE_MUTEX(bsg_mutex); |
| static DEFINE_IDR(bsg_minor_idr); |
| |
| #define BSG_LIST_ARRAY_SIZE 8 |
| static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; |
| |
| static struct class *bsg_class; |
| static int bsg_major; |
| |
| static inline struct hlist_head *bsg_dev_idx_hash(int index) |
| { |
| return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; |
| } |
| |
| #define uptr64(val) ((void __user *)(uintptr_t)(val)) |
| |
| static int bsg_scsi_check_proto(struct sg_io_v4 *hdr) |
| { |
| if (hdr->protocol != BSG_PROTOCOL_SCSI || |
| hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD) |
| return -EINVAL; |
| return 0; |
| } |
| |
| static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr, |
| fmode_t mode) |
| { |
| struct scsi_request *sreq = scsi_req(rq); |
| |
| sreq->cmd_len = hdr->request_len; |
| if (sreq->cmd_len > BLK_MAX_CDB) { |
| sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL); |
| if (!sreq->cmd) |
| return -ENOMEM; |
| } |
| |
| if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len)) |
| return -EFAULT; |
| if (blk_verify_command(sreq->cmd, mode)) |
| return -EPERM; |
| return 0; |
| } |
| |
| static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr) |
| { |
| struct scsi_request *sreq = scsi_req(rq); |
| int ret = 0; |
| |
| /* |
| * fill in all the output members |
| */ |
| hdr->device_status = sreq->result & 0xff; |
| hdr->transport_status = host_byte(sreq->result); |
| hdr->driver_status = driver_byte(sreq->result); |
| hdr->info = 0; |
| if (hdr->device_status || hdr->transport_status || hdr->driver_status) |
| hdr->info |= SG_INFO_CHECK; |
| hdr->response_len = 0; |
| |
| if (sreq->sense_len && hdr->response) { |
| int len = min_t(unsigned int, hdr->max_response_len, |
| sreq->sense_len); |
| |
| if (copy_to_user(uptr64(hdr->response), sreq->sense, len)) |
| ret = -EFAULT; |
| else |
| hdr->response_len = len; |
| } |
| |
| if (rq->next_rq) { |
| hdr->dout_resid = sreq->resid_len; |
| hdr->din_resid = scsi_req(rq->next_rq)->resid_len; |
| } else if (rq_data_dir(rq) == READ) { |
| hdr->din_resid = sreq->resid_len; |
| } else { |
| hdr->dout_resid = sreq->resid_len; |
| } |
| |
| return ret; |
| } |
| |
| static void bsg_scsi_free_rq(struct request *rq) |
| { |
| scsi_req_free_cmd(scsi_req(rq)); |
| } |
| |
| static const struct bsg_ops bsg_scsi_ops = { |
| .check_proto = bsg_scsi_check_proto, |
| .fill_hdr = bsg_scsi_fill_hdr, |
| .complete_rq = bsg_scsi_complete_rq, |
| .free_rq = bsg_scsi_free_rq, |
| }; |
| |
| static struct request * |
| bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode) |
| { |
| struct request *rq, *next_rq = NULL; |
| int ret; |
| |
| if (!q->bsg_dev.class_dev) |
| return ERR_PTR(-ENXIO); |
| |
| if (hdr->guard != 'Q') |
| return ERR_PTR(-EINVAL); |
| |
| ret = q->bsg_dev.ops->check_proto(hdr); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| rq = blk_get_request(q, hdr->dout_xfer_len ? |
| REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0); |
| if (IS_ERR(rq)) |
| return rq; |
| |
| ret = q->bsg_dev.ops->fill_hdr(rq, hdr, mode); |
| if (ret) |
| goto out; |
| |
| rq->timeout = msecs_to_jiffies(hdr->timeout); |
| if (!rq->timeout) |
| rq->timeout = q->sg_timeout; |
| if (!rq->timeout) |
| rq->timeout = BLK_DEFAULT_SG_TIMEOUT; |
| if (rq->timeout < BLK_MIN_SG_TIMEOUT) |
| rq->timeout = BLK_MIN_SG_TIMEOUT; |
| |
| if (hdr->dout_xfer_len && hdr->din_xfer_len) { |
| if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { |
| ret = -EOPNOTSUPP; |
| goto out; |
| } |
| |
| next_rq = blk_get_request(q, REQ_OP_SCSI_IN, 0); |
| if (IS_ERR(next_rq)) { |
| ret = PTR_ERR(next_rq); |
| goto out; |
| } |
| |
| rq->next_rq = next_rq; |
| ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr->din_xferp), |
| hdr->din_xfer_len, GFP_KERNEL); |
| if (ret) |
| goto out_free_nextrq; |
| } |
| |
| if (hdr->dout_xfer_len) { |
| ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->dout_xferp), |
| hdr->dout_xfer_len, GFP_KERNEL); |
| } else if (hdr->din_xfer_len) { |
| ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->din_xferp), |
| hdr->din_xfer_len, GFP_KERNEL); |
| } |
| |
| if (ret) |
| goto out_unmap_nextrq; |
| return rq; |
| |
| out_unmap_nextrq: |
| if (rq->next_rq) |
| blk_rq_unmap_user(rq->next_rq->bio); |
| out_free_nextrq: |
| if (rq->next_rq) |
| blk_put_request(rq->next_rq); |
| out: |
| q->bsg_dev.ops->free_rq(rq); |
| blk_put_request(rq); |
| return ERR_PTR(ret); |
| } |
| |
| static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, |
| struct bio *bio, struct bio *bidi_bio) |
| { |
| int ret; |
| |
| ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr); |
| |
| if (rq->next_rq) { |
| blk_rq_unmap_user(bidi_bio); |
| blk_put_request(rq->next_rq); |
| } |
| |
| blk_rq_unmap_user(bio); |
| rq->q->bsg_dev.ops->free_rq(rq); |
| blk_put_request(rq); |
| return ret; |
| } |
| |
| static struct bsg_device *bsg_alloc_device(void) |
| { |
| struct bsg_device *bd; |
| |
| bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); |
| if (unlikely(!bd)) |
| return NULL; |
| |
| spin_lock_init(&bd->lock); |
| bd->max_queue = BSG_DEFAULT_CMDS; |
| INIT_HLIST_NODE(&bd->dev_list); |
| return bd; |
| } |
| |
| static int bsg_put_device(struct bsg_device *bd) |
| { |
| struct request_queue *q = bd->queue; |
| |
| mutex_lock(&bsg_mutex); |
| |
| if (!refcount_dec_and_test(&bd->ref_count)) { |
| mutex_unlock(&bsg_mutex); |
| return 0; |
| } |
| |
| hlist_del(&bd->dev_list); |
| mutex_unlock(&bsg_mutex); |
| |
| bsg_dbg(bd, "tearing down\n"); |
| |
| /* |
| * close can always block |
| */ |
| kfree(bd); |
| blk_put_queue(q); |
| return 0; |
| } |
| |
| static struct bsg_device *bsg_add_device(struct inode *inode, |
| struct request_queue *rq, |
| struct file *file) |
| { |
| struct bsg_device *bd; |
| unsigned char buf[32]; |
| |
| lockdep_assert_held(&bsg_mutex); |
| |
| if (!blk_get_queue(rq)) |
| return ERR_PTR(-ENXIO); |
| |
| bd = bsg_alloc_device(); |
| if (!bd) { |
| blk_put_queue(rq); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| bd->queue = rq; |
| |
| refcount_set(&bd->ref_count, 1); |
| hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); |
| |
| strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); |
| bsg_dbg(bd, "bound to <%s>, max queue %d\n", |
| format_dev_t(buf, inode->i_rdev), bd->max_queue); |
| |
| return bd; |
| } |
| |
| static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) |
| { |
| struct bsg_device *bd; |
| |
| lockdep_assert_held(&bsg_mutex); |
| |
| hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { |
| if (bd->queue == q) { |
| refcount_inc(&bd->ref_count); |
| goto found; |
| } |
| } |
| bd = NULL; |
| found: |
| return bd; |
| } |
| |
| static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) |
| { |
| struct bsg_device *bd; |
| struct bsg_class_device *bcd; |
| |
| /* |
| * find the class device |
| */ |
| mutex_lock(&bsg_mutex); |
| bcd = idr_find(&bsg_minor_idr, iminor(inode)); |
| |
| if (!bcd) { |
| bd = ERR_PTR(-ENODEV); |
| goto out_unlock; |
| } |
| |
| bd = __bsg_get_device(iminor(inode), bcd->queue); |
| if (!bd) |
| bd = bsg_add_device(inode, bcd->queue, file); |
| |
| out_unlock: |
| mutex_unlock(&bsg_mutex); |
| return bd; |
| } |
| |
| static int bsg_open(struct inode *inode, struct file *file) |
| { |
| struct bsg_device *bd; |
| |
| bd = bsg_get_device(inode, file); |
| |
| if (IS_ERR(bd)) |
| return PTR_ERR(bd); |
| |
| file->private_data = bd; |
| return 0; |
| } |
| |
| static int bsg_release(struct inode *inode, struct file *file) |
| { |
| struct bsg_device *bd = file->private_data; |
| |
| file->private_data = NULL; |
| return bsg_put_device(bd); |
| } |
| |
| static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct bsg_device *bd = file->private_data; |
| int __user *uarg = (int __user *) arg; |
| int ret; |
| |
| switch (cmd) { |
| /* |
| * our own ioctls |
| */ |
| case SG_GET_COMMAND_Q: |
| return put_user(bd->max_queue, uarg); |
| case SG_SET_COMMAND_Q: { |
| int queue; |
| |
| if (get_user(queue, uarg)) |
| return -EFAULT; |
| if (queue < 1) |
| return -EINVAL; |
| |
| spin_lock_irq(&bd->lock); |
| bd->max_queue = queue; |
| spin_unlock_irq(&bd->lock); |
| return 0; |
| } |
| |
| /* |
| * SCSI/sg ioctls |
| */ |
| case SG_GET_VERSION_NUM: |
| case SCSI_IOCTL_GET_IDLUN: |
| case SCSI_IOCTL_GET_BUS_NUMBER: |
| case SG_SET_TIMEOUT: |
| case SG_GET_TIMEOUT: |
| case SG_GET_RESERVED_SIZE: |
| case SG_SET_RESERVED_SIZE: |
| case SG_EMULATED_HOST: |
| case SCSI_IOCTL_SEND_COMMAND: { |
| void __user *uarg = (void __user *) arg; |
| return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); |
| } |
| case SG_IO: { |
| struct request *rq; |
| struct bio *bio, *bidi_bio = NULL; |
| struct sg_io_v4 hdr; |
| int at_head; |
| |
| if (copy_from_user(&hdr, uarg, sizeof(hdr))) |
| return -EFAULT; |
| |
| rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode); |
| if (IS_ERR(rq)) |
| return PTR_ERR(rq); |
| |
| bio = rq->bio; |
| if (rq->next_rq) |
| bidi_bio = rq->next_rq->bio; |
| |
| at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); |
| blk_execute_rq(bd->queue, NULL, rq, at_head); |
| ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); |
| |
| if (copy_to_user(uarg, &hdr, sizeof(hdr))) |
| return -EFAULT; |
| |
| return ret; |
| } |
| default: |
| return -ENOTTY; |
| } |
| } |
| |
| static const struct file_operations bsg_fops = { |
| .open = bsg_open, |
| .release = bsg_release, |
| .unlocked_ioctl = bsg_ioctl, |
| .owner = THIS_MODULE, |
| .llseek = default_llseek, |
| }; |
| |
| void bsg_unregister_queue(struct request_queue *q) |
| { |
| struct bsg_class_device *bcd = &q->bsg_dev; |
| |
| if (!bcd->class_dev) |
| return; |
| |
| mutex_lock(&bsg_mutex); |
| idr_remove(&bsg_minor_idr, bcd->minor); |
| if (q->kobj.sd) |
| sysfs_remove_link(&q->kobj, "bsg"); |
| device_unregister(bcd->class_dev); |
| bcd->class_dev = NULL; |
| mutex_unlock(&bsg_mutex); |
| } |
| EXPORT_SYMBOL_GPL(bsg_unregister_queue); |
| |
| int bsg_register_queue(struct request_queue *q, struct device *parent, |
| const char *name, const struct bsg_ops *ops) |
| { |
| struct bsg_class_device *bcd; |
| dev_t dev; |
| int ret; |
| struct device *class_dev = NULL; |
| |
| /* |
| * we need a proper transport to send commands, not a stacked device |
| */ |
| if (!queue_is_rq_based(q)) |
| return 0; |
| |
| bcd = &q->bsg_dev; |
| memset(bcd, 0, sizeof(*bcd)); |
| |
| mutex_lock(&bsg_mutex); |
| |
| ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); |
| if (ret < 0) { |
| if (ret == -ENOSPC) { |
| printk(KERN_ERR "bsg: too many bsg devices\n"); |
| ret = -EINVAL; |
| } |
| goto unlock; |
| } |
| |
| bcd->minor = ret; |
| bcd->queue = q; |
| bcd->ops = ops; |
| dev = MKDEV(bsg_major, bcd->minor); |
| class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name); |
| if (IS_ERR(class_dev)) { |
| ret = PTR_ERR(class_dev); |
| goto idr_remove; |
| } |
| bcd->class_dev = class_dev; |
| |
| if (q->kobj.sd) { |
| ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); |
| if (ret) |
| goto unregister_class_dev; |
| } |
| |
| mutex_unlock(&bsg_mutex); |
| return 0; |
| |
| unregister_class_dev: |
| device_unregister(class_dev); |
| idr_remove: |
| idr_remove(&bsg_minor_idr, bcd->minor); |
| unlock: |
| mutex_unlock(&bsg_mutex); |
| return ret; |
| } |
| |
| int bsg_scsi_register_queue(struct request_queue *q, struct device *parent) |
| { |
| if (!blk_queue_scsi_passthrough(q)) { |
| WARN_ONCE(true, "Attempt to register a non-SCSI queue\n"); |
| return -EINVAL; |
| } |
| |
| return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops); |
| } |
| EXPORT_SYMBOL_GPL(bsg_scsi_register_queue); |
| |
| static struct cdev bsg_cdev; |
| |
| static char *bsg_devnode(struct device *dev, umode_t *mode) |
| { |
| return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); |
| } |
| |
| static int __init bsg_init(void) |
| { |
| int ret, i; |
| dev_t devid; |
| |
| for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) |
| INIT_HLIST_HEAD(&bsg_device_list[i]); |
| |
| bsg_class = class_create(THIS_MODULE, "bsg"); |
| if (IS_ERR(bsg_class)) |
| return PTR_ERR(bsg_class); |
| bsg_class->devnode = bsg_devnode; |
| |
| ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); |
| if (ret) |
| goto destroy_bsg_class; |
| |
| bsg_major = MAJOR(devid); |
| |
| cdev_init(&bsg_cdev, &bsg_fops); |
| ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); |
| if (ret) |
| goto unregister_chrdev; |
| |
| printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION |
| " loaded (major %d)\n", bsg_major); |
| return 0; |
| unregister_chrdev: |
| unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); |
| destroy_bsg_class: |
| class_destroy(bsg_class); |
| return ret; |
| } |
| |
| MODULE_AUTHOR("Jens Axboe"); |
| MODULE_DESCRIPTION(BSG_DESCRIPTION); |
| MODULE_LICENSE("GPL"); |
| |
| device_initcall(bsg_init); |