This is a note to let you know that I've just added the patch titled
scsi: core: Cap scsi_host cmd_per_lun at can_queue
to the 5.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-core-cap-scsi_host-cmd_per_lun-at-can_queue.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 999954bc56a1de02f3510207d99e0b39ca7eb527
Author: John Garry <john.garry@xxxxxxxxxx>
Date: Wed May 19 22:31:02 2021 +0800
scsi: core: Cap scsi_host cmd_per_lun at can_queue
[ Upstream commit ea2f0f77538c50739b9fb4de4700cee5535e1f77 ]
The sysfs handling function sdev_store_queue_depth() enforces that the sdev
queue depth cannot exceed shost can_queue. The initial sdev queue depth
comes from shost cmd_per_lun. However, the LLDD may manually set
cmd_per_lun to be larger than can_queue, which leads to an initial sdev
queue depth greater than can_queue.
Such an issue was reported in [0], which caused a hang. That has since been
fixed in commit fc09acb7de31 ("scsi: scsi_debug: Fix cmd_per_lun, set to
max_queue").
Stop this possibly happening for other drivers by capping shost cmd_per_lun
at shost can_queue.
[0] https://lore.kernel.org/linux-scsi/YHaez6iN2HHYxYOh@T590/
Link: https://lore.kernel.org/r/1621434662-173079-1-git-send-email-john.garry@xxxxxxxxxx
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 00ec0b9e9dbb..b40bb6bd5f5d 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -220,6 +220,9 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
goto fail;
}
+ shost->cmd_per_lun = min_t(short, shost->cmd_per_lun,
+ shost->can_queue);
+
error = scsi_init_sense_cache(shost);
if (error)
goto fail;
