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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: b05d4e481e ("scsi: scsi_debug: Refine sdebug_blk_mq_poll()")
Cc: stable@vger.kernel.org
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 2022-03-01 20:30:09 +09:00 committed by Martin K. Petersen
parent e9c478014b
commit 3fd07aecb7
1 changed files with 7 additions and 9 deletions
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16
drivers/scsi/scsi_debug.c
View File

@ -7509,7 +7509,6 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
{
bool first;
bool retiring = false;
bool locked = false;
int num_entries = 0;
unsigned int qc_idx = 0;
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)
return 0;
spin_lock_irqsave(&sqp->qc_lock, iflags);
for (first = true; first || qc_idx + 1 < sdebug_max_queue; ) {
if (!locked) {
spin_lock_irqsave(&sqp->qc_lock, iflags);
locked = true;
}
if (first) {
first = false;
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);
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
locked = false;
scsi_done(scp); /* callback to mid level */
num_entries++;
spin_lock_irqsave(&sqp->qc_lock, iflags);
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)
atomic_add(num_entries, &sdeb_mq_poll_count);
return num_entries;