On 3/17/20 10:38 AM, John Garry wrote:

On 11/03/2020 08:10, Ming Lei wrote:

quoted

quoted

ands(struct ctlr_info *h)

@@ -5803,6 +5803,7 @@ static int hpsa_scsi_host_alloc(struct 

ctlr_info *h)
      sh->max_lun = HPSA_MAX_LUN;
      sh->max_id = HPSA_MAX_LUN;
      sh->can_queue = h->nr_cmds - HPSA_NRESERVED_CMDS;
+    sh->nr_reserved_cmds = HPSA_NRESERVED_CMDS;

Now .nr_reserved_cmds has been passed to blk-mq, you need to increase
sh->can_queue to h->nr_cmds, because .can_queue is the whole queue depth
(include the part of reserved tags), otherwise, IO tags will be
decreased.

Sounds correct.

I will have having a look at the patchset; I thought I did a patch to 
modify .can_queue so that it would cover only the usable tags, not the 
reserved ones.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke            Teamlead Storage & Networking
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