diff mbox series

[7/8] loop: only freeze the queue in __loop_clr_fd when needed

Message ID 20220128130022.1750906-8-hch@lst.de (mailing list archive)
State New, archived
Headers show
Series [1/8] loop: de-duplicate the idle worker freeing code | expand

Commit Message

Christoph Hellwig Jan. 28, 2022, 1 p.m. UTC 
->release is only called after all outstanding I/O has completed, so only
freeze the queue when clearing the backing file of a live loop device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Tested-by: Darrick J. Wong <djwong@kernel.org>
---
 drivers/block/loop.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 1ca70f735b5bc..0cdbc60037642 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1110,7 +1110,7 @@  static int loop_configure(struct loop_device *lo, fmode_t mode,
 	return error;
 }
 
-static void __loop_clr_fd(struct loop_device *lo)
+static void __loop_clr_fd(struct loop_device *lo, bool release)
 {
 	struct file *filp;
 	gfp_t gfp = lo->old_gfp_mask;
@@ -1139,8 +1139,13 @@  static void __loop_clr_fd(struct loop_device *lo)
 	if (test_bit(QUEUE_FLAG_WC, &lo->lo_queue->queue_flags))
 		blk_queue_write_cache(lo->lo_queue, false, false);
 
-	/* freeze request queue during the transition */
-	blk_mq_freeze_queue(lo->lo_queue);
+	/*
+	 * Freeze the request queue when unbinding on a live file descriptor and
+	 * thus an open device.  When called from ->release we are guaranteed
+	 * that there is no I/O in progress already.
+	 */
+	if (!release)
+		blk_mq_freeze_queue(lo->lo_queue);
 
 	destroy_workqueue(lo->workqueue);
 	loop_free_idle_workers(lo, true);
@@ -1163,7 +1168,8 @@  static void __loop_clr_fd(struct loop_device *lo)
 	/* let user-space know about this change */
 	kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE);
 	mapping_set_gfp_mask(filp->f_mapping, gfp);
-	blk_mq_unfreeze_queue(lo->lo_queue);
+	if (!release)
+		blk_mq_unfreeze_queue(lo->lo_queue);
 
 	disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE);
 
@@ -1201,7 +1207,7 @@  static void loop_rundown_workfn(struct work_struct *work)
 	struct block_device *bdev = lo->lo_device;
 	struct gendisk *disk = lo->lo_disk;
 
-	__loop_clr_fd(lo);
+	__loop_clr_fd(lo, true);
 	kobject_put(&bdev->bd_device.kobj);
 	module_put(disk->fops->owner);
 	loop_rundown_completed(lo);
@@ -1247,7 +1253,7 @@  static int loop_clr_fd(struct loop_device *lo)
 	lo->lo_state = Lo_rundown;
 	mutex_unlock(&lo->lo_mutex);
 
-	__loop_clr_fd(lo);
+	__loop_clr_fd(lo, false);
 	loop_rundown_completed(lo);
 	return 0;
 }