diff options
| author | Bart Van Assche <bvanassche@acm.org> | 2019-06-17 17:18:19 +0200 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2019-06-20 21:37:02 +0200 |
| commit | bbe9fb0d04b96dda1fd7bd973e094004978b2166 (patch) | |
| tree | ef796d2beef86a4d838ff4c0e47a2c26af82c852 | |
| parent | scsi: Restrict user space SCSI device state changes to "running" and "offline" (diff) | |
| download | linux-bbe9fb0d04b96dda1fd7bd973e094004978b2166.tar.xz linux-bbe9fb0d04b96dda1fd7bd973e094004978b2166.zip | |
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>
| -rw-r--r-- | drivers/scsi/scsi_error.c | 26 | ||||
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 4 |
2 files changed, 24 insertions, 6 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); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index b1b1a1aaa353..6c84edc53f05 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2616,10 +2616,6 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); * 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) { |