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: 3c85f087fa ("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>
This commit is contained in:
Can Guo 2023-12-18 07:32:17 -08:00 committed by Martin K. Petersen
parent 9264fd61e6
commit 04c116e2bd

View file

@ -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);