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scsi: scsi_debug: Fix sdebug_blk_mq_poll() in_use_bm bitmap use

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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: 3fd07aecb7 ("scsi: scsi_debug: Fix qc_lock use in sdebug_blk_mq_poll()")
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Damien Le Moal 2022-04-04 13:55:47 +09:00 committed by Martin K. Petersen
parent 5f3ecd7447
commit 6a0d0ae3e8
1 changed files with 5 additions and 3 deletions
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8
drivers/scsi/scsi_debug.c
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@ -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)