From 6c6ac8b7773f05f93dc4e4044686e059d1f78dea Mon Sep 17 00:00:00 2001 From: John Garry Date: Tue, 17 May 2022 16:04:21 +0800 Subject: scsi: hisi_sas: Fix memory ordering in hisi_sas_task_deliver() 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(). Link: https://lore.kernel.org/r/1652774661-12935-1-git-send-email-john.garry@huawei.com Fixes: 26fc0ea74fcb ("scsi: libsas: Drop SAS_TASK_AT_INITIATOR") Reported-by: Yihang Li Tested-by: Yihang Li Signed-off-by: John Garry Signed-off-by: Martin K. Petersen --- drivers/scsi/hisi_sas/hisi_sas_main.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/scsi') diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c index f81e74fd6263..764e859d0106 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); -- cgit v1.2.3