scsi: ufs: mcq: Prevent no I/O queue case for MCQ

If hba_maxq equals poll_queues, which means there are no I/O queues
(HCTX_TYPE_DEFAULT, HCTX_TYPE_READ), the very first hw queue will be
allocated as HCTX_TYPE_POLL and it will be used as the dev_cmd_queue.  In
this case, device commands such as QUERY cannot be properly handled.

This patch prevents the initialization of MCQ when the number of I/O queues
is not set and only the number of POLL queues is set.

Signed-off-by: Minwoo Im <minwoo.im@samsung.com>
Link: https://lore.kernel.org/r/20240531212244.1593535-3-minwoo.im@samsung.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
index 46faa54aea94e146d14f22bac6eb5e34a7306def..4bcae410c2681e5cfc6010f11f4f64f84cf45841 100644 (file)
--- a/drivers/ufs/core/ufs-mcq.c
+++ b/drivers/ufs/core/ufs-mcq.c
@@ -179,6 +179,15 @@ static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
                return -EOPNOTSUPP;
        }
 
+       /*
+        * Device should support at least one I/O queue to handle device
+        * commands via hba->dev_cmd_queue.
+        */
+       if (hba_maxq == poll_queues) {
+               dev_err(hba->dev, "At least one non-poll queue required\n");
+               return -EOPNOTSUPP;
+       }
+
        rem = hba_maxq;
 
        if (rw_queues) {