From: John Garry john.garry@huawei.com
[ 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@huaw... Reviewed-by: Ming Lei ming.lei@redhat.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: John Garry john.garry@huawei.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/hosts.c | 3 +++ 1 file changed, 3 insertions(+)
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;