Commit 6a0d0ae3 authored by Damien Le Moal's avatar Damien Le Moal Committed by Martin K. Petersen
Browse files

scsi: scsi_debug: Fix sdebug_blk_mq_poll() in_use_bm bitmap use 

The in_use_bm bitmap of struct sdebug_queue should be accessed under
protection of the qc_lock spinlock. Make sure that this lock is taken
before calling find_first_bit() at the beginning of the function
sdebug_blk_mq_poll().

Link: https://lore.kernel.org/r/20220404045547.579887-1-damien.lemoal@opensource.wdc.com


Fixes: 3fd07aec ("scsi: scsi_debug: Fix qc_lock use in sdebug_blk_mq_poll()")
Acked-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 5f3ecd74

drivers/scsi/scsi_debug.c

+5 −3
Original line number Diff line number Diff line
@@ -7519,12 +7519,13 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) 
	struct sdebug_defer *sd_dp;



	sqp = sdebug_q_arr + queue_num;

	qc_idx = find_first_bit(sqp->in_use_bm, sdebug_max_queue);

	if (qc_idx >= sdebug_max_queue)

		return 0;



	spin_lock_irqsave(&sqp->qc_lock, iflags);



	qc_idx = find_first_bit(sqp->in_use_bm, sdebug_max_queue);

	if (qc_idx >= sdebug_max_queue)

		goto unlock;



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

		if (first) {

			first = false;
@@ -7589,6 +7590,7 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num) 
			break;

	}



unlock:

	spin_unlock_irqrestore(&sqp->qc_lock, iflags);



	if (num_entries > 0)