diff options
| author | Bart Van Assche <bart.vanassche@wdc.com> | 2017-12-04 19:06:23 +0100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2017-12-08 03:06:31 +0100 |
| commit | 3bd6f43f5cb3714f70c591514f344389df593501 (patch) | |
| tree | 0d287d0b562c064adf4ce1b45c1ea0cb2b97b401 /drivers/scsi/scsi_error.c | |
| parent | rcu: Export init_rcu_head() and destroy_rcu_head() to GPL modules (diff) | |
| download | linux-3bd6f43f5cb3714f70c591514f344389df593501.tar.xz linux-3bd6f43f5cb3714f70c591514f344389df593501.zip | |
scsi: core: Ensure that the SCSI error handler gets woken up
If scsi_eh_scmd_add() is called concurrently with
scsi_host_queue_ready() while shost->host_blocked > 0 then it can
happen that neither function wakes up the SCSI error handler. Fix
this by making every function that decreases the host_busy counter
wake up the error handler if necessary and by protecting the
host_failed checks with the SCSI host lock.
Reported-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
References: https://marc.info/?l=linux-kernel&m=150461610630736
Fixes: commit 746650160866 ("scsi: convert host_busy to atomic_t")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Tested-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Cc: Konstantin Khorenko <khorenko@virtuozzo.com>
Cc: Stuart Hayes <stuart.w.hayes@gmail.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: <stable@vger.kernel.org>
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.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 62b56de38ae8..3737c6d3b064 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -220,6 +220,17 @@ static void scsi_eh_reset(struct scsi_cmnd *scmd) } } +static void scsi_eh_inc_host_failed(struct rcu_head *head) +{ + struct Scsi_Host *shost = container_of(head, typeof(*shost), rcu); + unsigned long flags; + + spin_lock_irqsave(shost->host_lock, flags); + shost->host_failed++; + scsi_eh_wakeup(shost); + spin_unlock_irqrestore(shost->host_lock, flags); +} + /** * scsi_eh_scmd_add - add scsi cmd to error handling. * @scmd: scmd to run eh on. @@ -242,9 +253,12 @@ void scsi_eh_scmd_add(struct scsi_cmnd *scmd) scsi_eh_reset(scmd); list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q); - shost->host_failed++; - scsi_eh_wakeup(shost); spin_unlock_irqrestore(shost->host_lock, flags); + /* + * Ensure that all tasks observe the host state change before the + * host_failed change. + */ + call_rcu(&shost->rcu, scsi_eh_inc_host_failed); } /** |