* [PATCH] scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver()
@ 2022-05-17 8:04 John Garry
2022-05-18 1:19 ` Martin K. Petersen
2022-05-20 1:09 ` Martin K. Petersen
0 siblings, 2 replies; 3+ messages in thread
From: John Garry @ 2022-05-17 8:04 UTC (permalink / raw)
To: jejb, martin.petersen; +Cc: linux-scsi, linux-kernel, linuxarm, John Garry
The memories for the slot should be observed to be written prior to
observing the slot as ready.
Prior to commit 26fc0ea74fcb ("scsi: libsas: Drop SAS_TASK_AT_INITIATOR"),
we had a spin_lock() + spin_unlock() immediately before marking the slot
as ready. The spin_unlock() - with release semantics - caused the slot
memory to be observed to be written.
Now that the spin_lock() + spin_unlock() is gone, use a smp_wmb().
Fixes: 26fc0ea74fcb ("scsi: libsas: Drop SAS_TASK_AT_INITIATOR")
Reported-by: Yihang Li <liyihang6@hisilicon.com>
Tested-by: Yihang Li <liyihang6@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
---
Hi Martin, Please consider for v5.18, thanks!
diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 4bda2f6cb352..f56dd01230ce 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -446,6 +446,8 @@ void hisi_sas_task_deliver(struct hisi_hba *hisi_hba,
return;
}
+ /* Make slot memories observable before marking as ready */
+ smp_wmb();
WRITE_ONCE(slot->ready, 1);
spin_lock(&dq->lock);
--
2.26.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver()
2022-05-17 8:04 [PATCH] scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver() John Garry
@ 2022-05-18 1:19 ` Martin K. Petersen
2022-05-20 1:09 ` Martin K. Petersen
1 sibling, 0 replies; 3+ messages in thread
From: Martin K. Petersen @ 2022-05-18 1:19 UTC (permalink / raw)
To: John Garry; +Cc: jejb, martin.petersen, linux-scsi, linux-kernel, linuxarm
John,
> The memories for the slot should be observed to be written prior to
> observing the slot as ready.
Applied to 5.19/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver()
2022-05-17 8:04 [PATCH] scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver() John Garry
2022-05-18 1:19 ` Martin K. Petersen
@ 2022-05-20 1:09 ` Martin K. Petersen
1 sibling, 0 replies; 3+ messages in thread
From: Martin K. Petersen @ 2022-05-20 1:09 UTC (permalink / raw)
To: John Garry, jejb; +Cc: Martin K . Petersen, linux-scsi, linuxarm, linux-kernel
On Tue, 17 May 2022 16:04:21 +0800, John Garry wrote:
> The memories for the slot should be observed to be written prior to
> observing the slot as ready.
>
> Prior to commit 26fc0ea74fcb ("scsi: libsas: Drop SAS_TASK_AT_INITIATOR"),
> we had a spin_lock() + spin_unlock() immediately before marking the slot
> as ready. The spin_unlock() - with release semantics - caused the slot
> memory to be observed to be written.
>
> [...]
Applied to 5.19/scsi-queue, thanks!
[1/1] scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver()
https://git.kernel.org/mkp/scsi/c/6c6ac8b7773f
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-05-20 1:10 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-17 8:04 [PATCH] scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver() John Garry
2022-05-18 1:19 ` Martin K. Petersen
2022-05-20 1:09 ` Martin K. Petersen
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).