[SCSI] libsas: enforce eh strategy handlers only in eh context
The strategy handlers may be called in places that are problematic for
libsas (i.e. sata resets outside of domain revalidation filtering /
libata link recovery), or problematic for userspace (non-blocking ioctl
to sleeping reset functions). However, these routines are also called
for eh escalations and recovery of scsi_eh_prep_cmnd(), so permit them
as long as we are running in the host's error handler, otherwise arrange
for them to be triggered in eh_context.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index ff497ac..b031d23 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -39,6 +39,7 @@
{
switch (dev->dev_type) {
case SAS_END_DEV:
+ INIT_LIST_HEAD(&dev->ssp_dev.eh_list_node);
break;
case EDGE_DEV:
case FANOUT_DEV:
@@ -286,6 +287,8 @@
static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_device *dev)
{
+ struct sas_ha_struct *ha = port->ha;
+
sas_notify_lldd_dev_gone(dev);
if (!dev->parent)
dev->port->port_dev = NULL;
@@ -298,6 +301,14 @@
sas_ata_end_eh(dev->sata_dev.ap);
spin_unlock_irq(&port->dev_list_lock);
+ spin_lock_irq(&ha->lock);
+ if (dev->dev_type == SAS_END_DEV &&
+ !list_empty(&dev->ssp_dev.eh_list_node)) {
+ list_del_init(&dev->ssp_dev.eh_list_node);
+ ha->eh_active--;
+ }
+ spin_unlock_irq(&ha->lock);
+
sas_put_device(dev);
}
diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index 6909fef..1bbab3d 100644
--- a/drivers/scsi/libsas/sas_init.c
+++ b/drivers/scsi/libsas/sas_init.c
@@ -116,7 +116,9 @@
set_bit(SAS_HA_REGISTERED, &sas_ha->state);
spin_lock_init(&sas_ha->lock);
mutex_init(&sas_ha->drain_mutex);
+ init_waitqueue_head(&sas_ha->eh_wait_q);
INIT_LIST_HEAD(&sas_ha->defer_q);
+ INIT_LIST_HEAD(&sas_ha->eh_dev_q);
error = sas_register_phys(sas_ha);
if (error) {
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 52d5b01..2e0e779 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -460,14 +460,88 @@
}
EXPORT_SYMBOL_GPL(sas_get_local_phy);
+static void sas_wait_eh(struct domain_device *dev)
+{
+ struct sas_ha_struct *ha = dev->port->ha;
+ DEFINE_WAIT(wait);
+
+ if (dev_is_sata(dev)) {
+ ata_port_wait_eh(dev->sata_dev.ap);
+ return;
+ }
+ retry:
+ spin_lock_irq(&ha->lock);
+
+ while (test_bit(SAS_DEV_EH_PENDING, &dev->state)) {
+ prepare_to_wait(&ha->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock_irq(&ha->lock);
+ schedule();
+ spin_lock_irq(&ha->lock);
+ }
+ finish_wait(&ha->eh_wait_q, &wait);
+
+ spin_unlock_irq(&ha->lock);
+
+ /* make sure SCSI EH is complete */
+ if (scsi_host_in_recovery(ha->core.shost)) {
+ msleep(10);
+ goto retry;
+ }
+}
+EXPORT_SYMBOL(sas_wait_eh);
+
+static int sas_queue_reset(struct domain_device *dev, int reset_type, int lun, int wait)
+{
+ struct sas_ha_struct *ha = dev->port->ha;
+ int scheduled = 0, tries = 100;
+
+ /* ata: promote lun reset to bus reset */
+ if (dev_is_sata(dev)) {
+ sas_ata_schedule_reset(dev);
+ if (wait)
+ sas_ata_wait_eh(dev);
+ return SUCCESS;
+ }
+
+ while (!scheduled && tries--) {
+ spin_lock_irq(&ha->lock);
+ if (!test_bit(SAS_DEV_EH_PENDING, &dev->state) &&
+ !test_bit(reset_type, &dev->state)) {
+ scheduled = 1;
+ ha->eh_active++;
+ list_add_tail(&dev->ssp_dev.eh_list_node, &ha->eh_dev_q);
+ set_bit(SAS_DEV_EH_PENDING, &dev->state);
+ set_bit(reset_type, &dev->state);
+ int_to_scsilun(lun, &dev->ssp_dev.reset_lun);
+ scsi_schedule_eh(ha->core.shost);
+ }
+ spin_unlock_irq(&ha->lock);
+
+ if (wait)
+ sas_wait_eh(dev);
+
+ if (scheduled)
+ return SUCCESS;
+ }
+
+ SAS_DPRINTK("%s reset of %s failed\n",
+ reset_type == SAS_DEV_LU_RESET ? "LUN" : "Bus",
+ dev_name(&dev->rphy->dev));
+
+ return FAILED;
+}
+
/* Attempt to send a LUN reset message to a device */
int sas_eh_device_reset_handler(struct scsi_cmnd *cmd)
{
- struct domain_device *dev = cmd_to_domain_dev(cmd);
- struct sas_internal *i =
- to_sas_internal(dev->port->ha->core.shost->transportt);
- struct scsi_lun lun;
int res;
+ struct scsi_lun lun;
+ struct Scsi_Host *host = cmd->device->host;
+ struct domain_device *dev = cmd_to_domain_dev(cmd);
+ struct sas_internal *i = to_sas_internal(host->transportt);
+
+ if (current != host->ehandler)
+ return sas_queue_reset(dev, SAS_DEV_LU_RESET, cmd->device->lun, 0);
int_to_scsilun(cmd->device->lun, &lun);
@@ -486,8 +560,12 @@
{
struct domain_device *dev = cmd_to_domain_dev(cmd);
struct sas_phy *phy = sas_get_local_phy(dev);
+ struct Scsi_Host *host = cmd->device->host;
int res;
+ if (current != host->ehandler)
+ return sas_queue_reset(dev, SAS_DEV_RESET, 0, 0);
+
res = sas_phy_reset(phy, 1);
if (res)
SAS_DPRINTK("Bus reset of %s failed 0x%x\n",
@@ -667,6 +745,39 @@
goto out;
}
+static void sas_eh_handle_resets(struct Scsi_Host *shost)
+{
+ struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
+ struct sas_internal *i = to_sas_internal(shost->transportt);
+
+ /* handle directed resets to sas devices */
+ spin_lock_irq(&ha->lock);
+ while (!list_empty(&ha->eh_dev_q)) {
+ struct domain_device *dev;
+ struct ssp_device *ssp;
+
+ ssp = list_entry(ha->eh_dev_q.next, typeof(*ssp), eh_list_node);
+ list_del_init(&ssp->eh_list_node);
+ dev = container_of(ssp, typeof(*dev), ssp_dev);
+ kref_get(&dev->kref);
+ WARN_ONCE(dev_is_sata(dev), "ssp reset to ata device?\n");
+
+ spin_unlock_irq(&ha->lock);
+
+ if (test_and_clear_bit(SAS_DEV_LU_RESET, &dev->state))
+ i->dft->lldd_lu_reset(dev, ssp->reset_lun.scsi_lun);
+
+ if (test_and_clear_bit(SAS_DEV_RESET, &dev->state))
+ i->dft->lldd_I_T_nexus_reset(dev);
+
+ sas_put_device(dev);
+ spin_lock_irq(&ha->lock);
+ clear_bit(SAS_DEV_EH_PENDING, &dev->state);
+ ha->eh_active--;
+ }
+ spin_unlock_irq(&ha->lock);
+}
+
void sas_scsi_recover_host(struct Scsi_Host *shost)
{
@@ -709,6 +820,8 @@
if (ha->lldd_max_execute_num > 1)
wake_up_process(ha->core.queue_thread);
+ sas_eh_handle_resets(shost);
+
/* now link into libata eh --- if we have any ata devices */
sas_ata_strategy_handler(shost);
