From 04c116e2bdfc3969f9819d2cebfdf678353c354c Mon Sep 17 00:00:00 2001
From: Can Guo <quic_cang@quicinc.com>
Date: Mon, 18 Dec 2023 07:32:17 -0800
Subject: [PATCH] scsi: ufs: core: Let the sq_lock protect sq_tail_slot access
When accessing sq_tail_slot without protection from sq_lock, a race
condition can cause multiple SQEs to be copied to duplicate SQE slots. This
can lead to multiple stability issues. Fix this by moving the *dest
initialization in ufshcd_send_command() back under protection from the
sq_lock.
Fixes: 3c85f087faec ("scsi: ufs: mcq: Use pointer arithmetic in ufshcd_send_command()")
Signed-off-by: Can Guo <quic_cang@quicinc.com>
Link: https://lore.kernel.org/r/1702913550-20631-1-git-send-email-quic_cang@quicinc.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
drivers/ufs/core/ufshcd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index bce0d2a9a7f3a..16d76325039a5 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -2274,9 +2274,10 @@ void ufshcd_send_command(struct ufs_hba *hba, unsigned int task_tag,
if (is_mcq_enabled(hba)) {
int utrd_size = sizeof(struct utp_transfer_req_desc);
struct utp_transfer_req_desc *src = lrbp->utr_descriptor_ptr;
- struct utp_transfer_req_desc *dest = hwq->sqe_base_addr + hwq->sq_tail_slot;
+ struct utp_transfer_req_desc *dest;
spin_lock(&hwq->sq_lock);
+ dest = hwq->sqe_base_addr + hwq->sq_tail_slot;
memcpy(dest, src, utrd_size);
ufshcd_inc_sq_tail(hwq);
spin_unlock(&hwq->sq_lock);
--
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