Commit 04c116e2 authored by Can Guo's avatar Can Guo Committed by Martin K. Petersen
Browse files

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: 3c85f087 ("scsi: ufs: mcq: Use pointer arithmetic in ufshcd_send_command()")
Signed-off-by: default avatarCan Guo <quic_cang@quicinc.com>
Link: https://lore.kernel.org/r/1702913550-20631-1-git-send-email-quic_cang@quicinc.com


Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 9264fd61

drivers/ufs/core/ufshcd.c

+2 −1
Original line number Diff line number Diff line
@@ -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);