Commit 3fd07aec authored by Damien Le Moal's avatar Damien Le Moal Committed by Martin K. Petersen
Browse files

scsi: scsi_debug: Fix qc_lock use in sdebug_blk_mq_poll() 

The use of the 'locked' boolean variable to control locking and unlocking
of the qc_lock spinlock of struct sdebug_queue confuses sparse, leading to
a warning about an unexpected unlock. Simplify the qc_lock lock/unlock
handling code of this function to avoid this warning by removing the
'locked' boolean variable. This change also fixes unlocked access to the
in_use_bm bitmap with the find_first_bit() function.

Link: https://lore.kernel.org/r/20220301113009.595857-3-damien.lemoal@opensource.wdc.com


Fixes: b05d4e48 ("scsi: scsi_debug: Refine sdebug_blk_mq_poll()")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent e9c47801

drivers/scsi/scsi_debug.c

+7 −9
Original line number Original line Diff line number Diff line
@@ -7509,7 +7509,6 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) 
{

{

	bool first;

	bool first;

	bool retiring = false;

	bool retiring = false;

	bool locked = false;

	int num_entries = 0;

	int num_entries = 0;

	unsigned int qc_idx = 0;

	unsigned int qc_idx = 0;

	unsigned long iflags;

	unsigned long iflags;
@@ -7525,11 +7524,9 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) 
	if (qc_idx >= sdebug_max_queue)

	if (qc_idx >= sdebug_max_queue)

		return 0;

		return 0;





	for (first = true; first || qc_idx + 1 < sdebug_max_queue; )   {

		if (!locked) {

	spin_lock_irqsave(&sqp->qc_lock, iflags);

	spin_lock_irqsave(&sqp->qc_lock, iflags);

			locked = true;



		}

	for (first = true; first || qc_idx + 1 < sdebug_max_queue; )   {

		if (first) {

		if (first) {

			first = false;

			first = false;

			if (!test_bit(qc_idx, sqp->in_use_bm))

			if (!test_bit(qc_idx, sqp->in_use_bm))
@@ -7586,14 +7583,15 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) 
		}

		}

		WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_NONE);

		WRITE_ONCE(sd_dp->defer_t, SDEB_DEFER_NONE);

		spin_unlock_irqrestore(&sqp->qc_lock, iflags);

		spin_unlock_irqrestore(&sqp->qc_lock, iflags);

		locked = false;

		scsi_done(scp); /* callback to mid level */

		scsi_done(scp); /* callback to mid level */

		num_entries++;

		num_entries++;

		spin_lock_irqsave(&sqp->qc_lock, iflags);

		if (find_first_bit(sqp->in_use_bm, sdebug_max_queue) >= sdebug_max_queue)

		if (find_first_bit(sqp->in_use_bm, sdebug_max_queue) >= sdebug_max_queue)

			break;	/* if no more then exit without retaking spinlock */

			break;

	}

	}

	if (locked)



	spin_unlock_irqrestore(&sqp->qc_lock, iflags);

	spin_unlock_irqrestore(&sqp->qc_lock, iflags);



	if (num_entries > 0)

	if (num_entries > 0)

		atomic_add(num_entries, &sdeb_mq_poll_count);

		atomic_add(num_entries, &sdeb_mq_poll_count);

	return num_entries;

	return num_entries;