| Message ID | 1652774661-12935-1-git-send-email-john.garry@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver() | expand |
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
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);
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!