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authorBart Van Assche <bart.vanassche@wdc.com>2017-12-04 21:06:23 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2017-12-08 05:06:31 +0300
commit3bd6f43f5cb3714f70c591514f344389df593501 (patch)
tree0d287d0b562c064adf4ce1b45c1ea0cb2b97b401 /drivers/scsi/hosts.c
parent156baec39732f025dc778e00da95fc10d6e45885 (diff)
downloadlinux-3bd6f43f5cb3714f70c591514f344389df593501.tar.xz
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/hosts.c')
-rw-r--r--drivers/scsi/hosts.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index fe3a0da3ec97..57bf43e34863 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -318,6 +318,9 @@ static void scsi_host_dev_release(struct device *dev)
scsi_proc_hostdir_rm(shost->hostt);
+ /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
+ rcu_barrier();
+
if (shost->tmf_work_q)
destroy_workqueue(shost->tmf_work_q);
if (shost->ehandler)
@@ -325,6 +328,8 @@ static void scsi_host_dev_release(struct device *dev)
if (shost->work_q)
destroy_workqueue(shost->work_q);
+ destroy_rcu_head(&shost->rcu);
+
if (shost->shost_state == SHOST_CREATED) {
/*
* Free the shost_dev device name here if scsi_host_alloc()
@@ -399,6 +404,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
INIT_LIST_HEAD(&shost->starved_list);
init_waitqueue_head(&shost->host_wait);
mutex_init(&shost->scan_mutex);
+ init_rcu_head(&shost->rcu);
index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
if (index < 0)