Re: udev queue error

[Tejun Heo <htejun@xxxxxxxxx>]

And here's a patch which triggers clearing check on close.  It's on
top of the following branch + the previous patch.

  git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-2.6-block.git for-linus

With the patch applied, eject triggers MEDIA_CHANGE if the drive had a
media in it.

Thanks.

---
 block/genhd.c         |   22 ++++++++++++----------
 fs/block_dev.c        |   17 ++++++++---------
 include/linux/genhd.h |    2 +-
 3 files changed, 21 insertions(+), 20 deletions(-)

Index: work/block/genhd.c
===================================================================
--- work.orig/block/genhd.c
+++ work/block/genhd.c
@@ -1500,30 +1500,32 @@ void disk_unblock_events(struct gendisk 
 }
 
 /**
- * disk_check_events - schedule immediate event checking
- * @disk: disk to check events for
+ * disk_flush_events - schedule immediate event checking and flushing
+ * @disk: disk to check and flush events for
+ * @mask: events to flush
  *
- * Schedule immediate event checking on @disk if not blocked.
+ * Schedule immediate event checking on @disk if not blocked.  Events in
+ * @mask are scheduled to be cleared from the driver.  Note that this
+ * doesn't clear the events from @disk->ev.
  *
  * CONTEXT:
- * Don't care.  Safe to call from irq context.
+ * If @mask is non-zero must be called with bdev->bd_mutex held.
  */
-void disk_check_events(struct gendisk *disk)
+void disk_flush_events(struct gendisk *disk, unsigned int mask)
 {
 	struct disk_events *ev = disk->ev;
-	unsigned long flags;
 
 	if (!ev)
 		return;
 
-	spin_lock_irqsave(&ev->lock, flags);
+	spin_lock_irq(&ev->lock);
+	ev->clearing |= mask;
 	if (!ev->block) {
 		cancel_delayed_work(&ev->dwork);
 		queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
 	}
-	spin_unlock_irqrestore(&ev->lock, flags);
+	spin_unlock_irq(&ev->lock);
 }
-EXPORT_SYMBOL_GPL(disk_check_events);
 
 /**
  * disk_clear_events - synchronously check, clear and return pending events
@@ -1713,7 +1715,7 @@ static int disk_events_set_dfl_poll_msec
 	mutex_lock(&disk_events_mutex);
 
 	list_for_each_entry(ev, &disk_events, node)
-		disk_check_events(ev->disk);
+		disk_flush_events(ev->disk, 0);
 
 	mutex_unlock(&disk_events_mutex);
 
Index: work/fs/block_dev.c
===================================================================
--- work.orig/fs/block_dev.c
+++ work/fs/block_dev.c
@@ -1447,6 +1447,8 @@ static int __blkdev_put(struct block_dev
 
 int blkdev_put(struct block_device *bdev, fmode_t mode)
 {
+	mutex_lock(&bdev->bd_mutex);
+
 	if (mode & FMODE_EXCL) {
 		bool bdev_free;
 
@@ -1455,7 +1457,6 @@ int blkdev_put(struct block_device *bdev
 		 * are protected with bdev_lock.  bd_mutex is to
 		 * synchronize disk_holder unlinking.
 		 */
-		mutex_lock(&bdev->bd_mutex);
 		spin_lock(&bdev_lock);
 
 		WARN_ON_ONCE(--bdev->bd_holders < 0);
@@ -1473,17 +1474,15 @@ int blkdev_put(struct block_device *bdev
 		 * If this was the last claim, remove holder link and
 		 * unblock evpoll if it was a write holder.
 		 */
-		if (bdev_free) {
-			if (bdev->bd_write_holder) {
-				disk_unblock_events(bdev->bd_disk);
-				disk_check_events(bdev->bd_disk);
-				bdev->bd_write_holder = false;
-			}
+		if (bdev_free && bdev->bd_write_holder) {
+			disk_unblock_events(bdev->bd_disk);
+			bdev->bd_write_holder = false;
 		}
-
-		mutex_unlock(&bdev->bd_mutex);
 	}
 
+	disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE);
+	mutex_unlock(&bdev->bd_mutex);
+
 	return __blkdev_put(bdev, mode, 0);
 }
 EXPORT_SYMBOL(blkdev_put);
Index: work/include/linux/genhd.h
===================================================================
--- work.orig/include/linux/genhd.h
+++ work/include/linux/genhd.h
@@ -420,7 +420,7 @@ static inline int get_disk_ro(struct gen
 
 extern void disk_block_events(struct gendisk *disk);
 extern void disk_unblock_events(struct gendisk *disk);
-extern void disk_check_events(struct gendisk *disk);
+extern void disk_flush_events(struct gendisk *disk, unsigned int mask);
 extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
 
 /* drivers/char/random.c */
--
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