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authorBart Van Assche <bvanassche@acm.org>2019-06-17 08:18:19 -0700
committerMartin K. Petersen <martin.petersen@oracle.com>2019-06-20 15:37:02 -0400
commitbbe9fb0d04b96dda1fd7bd973e094004978b2166 (patch)
treeef796d2beef86a4d838ff4c0e47a2c26af82c852 /drivers/scsi/scsi_error.c
parentac88c1f6730e73771dc36b9fd83804e7aa15941a (diff)
scsi: Avoid that .queuecommand() gets called for a blocked SCSI device
Several SCSI transport and LLD drivers surround code that does not tolerate concurrent calls of .queuecommand() with scsi_target_block() / scsi_target_unblock(). These last two functions use blk_mq_quiesce_queue() / blk_mq_unquiesce_queue() for scsi-mq request queues to prevent concurrent .queuecommand() calls. However, that is not sufficient to prevent .queuecommand() calls from scsi_send_eh_cmnd(). Hence surround the .queuecommand() call from the SCSI error handler with code that avoids that .queuecommand() gets called in the blocked state. Note: converting the .queuecommand() call in scsi_send_eh_cmnd() into code that calls blk_get_request() + blk_execute_rq() is not an option since scsi_send_eh_cmnd() must be able to make forward progress even if all requests have been allocated. Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/scsi_error.c')
-rw-r--r--drivers/scsi/scsi_error.c26
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index f490994374f6..9f16304150b1 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1055,7 +1055,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
struct scsi_device *sdev = scmd->device;
struct Scsi_Host *shost = sdev->host;
DECLARE_COMPLETION_ONSTACK(done);
- unsigned long timeleft = timeout;
+ unsigned long timeleft = timeout, delay;
struct scsi_eh_save ses;
const unsigned long stall_for = msecs_to_jiffies(100);
int rtn;
@@ -1066,7 +1066,29 @@ retry:
scsi_log_send(scmd);
scmd->scsi_done = scsi_eh_done;
- rtn = shost->hostt->queuecommand(shost, scmd);
+
+ /*
+ * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
+ * change the SCSI device state after we have examined it and before
+ * .queuecommand() is called.
+ */
+ mutex_lock(&sdev->state_mutex);
+ while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
+ mutex_unlock(&sdev->state_mutex);
+ SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
+ "%s: state %d <> %d\n", __func__, sdev->sdev_state,
+ SDEV_BLOCK));
+ delay = min(timeleft, stall_for);
+ timeleft -= delay;
+ msleep(jiffies_to_msecs(delay));
+ mutex_lock(&sdev->state_mutex);
+ }
+ if (sdev->sdev_state != SDEV_BLOCK)
+ rtn = shost->hostt->queuecommand(shost, scmd);
+ else
+ rtn = SCSI_MLQUEUE_DEVICE_BUSY;
+ mutex_unlock(&sdev->state_mutex);
+
if (rtn) {
if (timeleft > stall_for) {
scsi_eh_restore_cmnd(scmd, &ses);