Commit 25b80b2c authored by John Garry's avatar John Garry Committed by Martin K. Petersen
Browse files

scsi: scsi_debug: Protect block_unblock_all_queues() with mutex 



There is no reason that calls to block_unblock_all_queues() from different
context can't race with one another, so protect with the
sdebug_host_list_mutex. There's no need for a more fine-grained per shost
locking here (and we don't have a per-host lock anyway).

Also simplify some touched code in sdebug_change_qdepth().

Signed-off-by: default avatarJohn Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20230327074310.1862889-5-john.g.garry@oracle.com


Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 0aaa3fad

drivers/scsi/scsi_debug.c

+17 −1
Original line number Diff line number Diff line
@@ -5497,6 +5497,8 @@ static void block_unblock_all_queues(bool block) 
	int j;

	struct sdebug_queue *sqp;



	lockdep_assert_held(&sdebug_host_list_mutex);



	for (j = 0, sqp = sdebug_q_arr; j < submit_queues; ++j, ++sqp)

		atomic_set(&sqp->blocked, (int)block);

}
@@ -5511,10 +5513,13 @@ static void tweak_cmnd_count(void) 
	modulo = abs(sdebug_every_nth);

	if (modulo < 2)

		return;



	mutex_lock(&sdebug_host_list_mutex);

	block_unblock_all_queues(true);

	count = atomic_read(&sdebug_cmnd_count);

	atomic_set(&sdebug_cmnd_count, (count / modulo) * modulo);

	block_unblock_all_queues(false);

	mutex_unlock(&sdebug_host_list_mutex);

}



static void clear_queue_stats(void)
@@ -6036,6 +6041,7 @@ static ssize_t delay_store(struct device_driver *ddp, const char *buf, 
			int j, k;

			struct sdebug_queue *sqp;



			mutex_lock(&sdebug_host_list_mutex);

			block_unblock_all_queues(true);

			for (j = 0, sqp = sdebug_q_arr; j < submit_queues;

			     ++j, ++sqp) {
@@ -6051,6 +6057,7 @@ static ssize_t delay_store(struct device_driver *ddp, const char *buf, 
				sdebug_ndelay = 0;

			}

			block_unblock_all_queues(false);

			mutex_unlock(&sdebug_host_list_mutex);

		}

		return res;

	}
@@ -6076,6 +6083,7 @@ static ssize_t ndelay_store(struct device_driver *ddp, const char *buf, 
			int j, k;

			struct sdebug_queue *sqp;



			mutex_lock(&sdebug_host_list_mutex);

			block_unblock_all_queues(true);

			for (j = 0, sqp = sdebug_q_arr; j < submit_queues;

			     ++j, ++sqp) {
@@ -6092,6 +6100,7 @@ static ssize_t ndelay_store(struct device_driver *ddp, const char *buf, 
							: DEF_JDELAY;

			}

			block_unblock_all_queues(false);

			mutex_unlock(&sdebug_host_list_mutex);

		}

		return res;

	}
@@ -6405,6 +6414,7 @@ static ssize_t max_queue_store(struct device_driver *ddp, const char *buf, 
	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n > 0) &&

	    (n <= SDEBUG_CANQUEUE) &&

	    (sdebug_host_max_queue == 0)) {

		mutex_lock(&sdebug_host_list_mutex);

		block_unblock_all_queues(true);

		k = 0;

		for (j = 0, sqp = sdebug_q_arr; j < submit_queues;
@@ -6421,6 +6431,7 @@ static ssize_t max_queue_store(struct device_driver *ddp, const char *buf, 
		else

			atomic_set(&retired_max_queue, 0);

		block_unblock_all_queues(false);

		mutex_unlock(&sdebug_host_list_mutex);

		return count;

	}

	return -EINVAL;
@@ -7352,7 +7363,9 @@ static int sdebug_change_qdepth(struct scsi_device *sdev, int qdepth) 
	if (!devip)

		return	-ENODEV;



	mutex_lock(&sdebug_host_list_mutex);

	block_unblock_all_queues(true);



	if (qdepth > SDEBUG_CANQUEUE) {

		qdepth = SDEBUG_CANQUEUE;

		pr_warn("%s: requested qdepth [%d] exceeds canqueue [%d], trim\n", __func__,
@@ -7363,9 +7376,12 @@ static int sdebug_change_qdepth(struct scsi_device *sdev, int qdepth) 
	if (qdepth != sdev->queue_depth)

		scsi_change_queue_depth(sdev, qdepth);



	block_unblock_all_queues(false);

	mutex_unlock(&sdebug_host_list_mutex);



	if (SDEBUG_OPT_Q_NOISE & sdebug_opts)

		sdev_printk(KERN_INFO, sdev, "%s: qdepth=%d\n", __func__, qdepth);

	block_unblock_all_queues(false);



	return sdev->queue_depth;

}