[PATCH v3 01/11] scsi: scsi_debug: Fix check for sdev queue full

[John Garry]

There is a report that the blktests scsi/004 test for "TASK SET FULL" (TSF)
now fails.

The condition upon we should issue this TSF is when the sdev queue is
full. The check for a full queue has an off-by-1 error. Previously we
would increment the number of requests in the queue after testing if the
queue would be full, i.e. test if one less than full. Since we now use
scsi_device_busy() to count the number of requests in the queue, this
would already account for the current request, so fix the test for queue
full accordingly.

Fixes: 151f0ec9ddb5 ("scsi: scsi_debug: Drop sdebug_dev_info.num_in_q")
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Link: https://lore.kernel.org/oe-lkp/202303201334.18b30edc-oliver.sang@xxxxxxxxx
Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
 drivers/scsi/scsi_debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 7ed117e78bd4..782515abca2c 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -5580,7 +5580,7 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
 		int num_in_q = scsi_device_busy(sdp);
 		int qdepth = cmnd->device->queue_depth;
 
-		if ((num_in_q == (qdepth - 1)) &&
+		if ((num_in_q == qdepth) &&
 		    (atomic_inc_return(&sdebug_a_tsf) >=
 		     abs(sdebug_every_nth))) {
 			atomic_set(&sdebug_a_tsf, 0);
-- 
2.35.3