From fab09aaee80389a37d8ab49396afbb77fa86583a Mon Sep 17 00:00:00 2001 From: John Garry Date: Thu, 15 Oct 2020 16:27:05 +0800 Subject: [PATCH] scsi: hisi_sas: Stop using queue #0 always for v2 hw In commit 8d98416a55eb ("scsi: hisi_sas: Switch v3 hw to MQ"), the dispatch function was changed to choose the delivery queue based on the request tag HW queue index. This heavily degrades performance for v2 hw, since the HW queues are not exposed there, and, as such, HW queue #0 is used for every command. Revert to previous behaviour for when nr_hw_queues is not set, that being to choose the HW queue based on target device index. Link: https://lore.kernel.org/r/1602750425-240341-1-git-send-email-john.garry@huawei.com Fixes: 8d98416a55eb ("scsi: hisi_sas: Switch v3 hw to MQ") Signed-off-by: John Garry Signed-off-by: Martin K. Petersen --- drivers/scsi/hisi_sas/hisi_sas_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c index 128583dfccf2..c8dd8588f800 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_main.c +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c @@ -445,7 +445,7 @@ static int hisi_sas_task_prep(struct sas_task *task, } } - if (scmd) { + if (scmd && hisi_hba->shost->nr_hw_queues) { unsigned int dq_index; u32 blk_tag; -- 2.11.0