path: root/block
diff options
authorTejun Heo <>2011-07-01 16:17:47 +0200
committerJens Axboe <>2011-07-01 16:17:47 +0200
commit85ef06d1d252f6a2e73b678591ab71caad4667bb (patch)
treedc5cbc4f2e54f5b5b3f8653a595799e5fe0f2f18 /block
parent04bf7869ca0fd12009aee301cac2264a36df4d98 (diff)
block: flush MEDIA_CHANGE from drivers on close(2)
Currently, only open(2) is defined as the 'clearing' point. It has two roles - first, it's an acknowledgement from userland indicating that the event has been received and kernel can clear pending states and proceed to generate more events. Secondly, it's passed on to device drivers as a hint indicating that a synchronization point has been reached and it might want to take a deeper look at the device. The latter currently is only used by sr which uses two different mechanisms - GET_EVENT_MEDIA_STATUS_NOTIFICATION and TEST_UNIT_READY to discover events, where the former is lighter weight and safe to be used repeatedly but may not provide full coverage. Among other things, GET_EVENT can't detect media removal while TUR can. This patch makes close(2) - blkdev_put() - indicate clearing hint for MEDIA_CHANGE to drivers. disk_check_events() is renamed to disk_flush_events() and updated to take @mask for events to flush which is or'd to ev->clearing and will be passed to the driver on the next ->check_events() invocation. This change makes sr generate MEDIA_CHANGE when media is ejected from userland - e.g. with eject(1). Note: Given the current usage, it seems @clearing hint is needlessly complex. disk_clear_events() can simply clear all events and the hint can be boolean @flush. Signed-off-by: Tejun Heo <> Cc: Kay Sievers <> Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block')
1 files changed, 12 insertions, 10 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 82d97c3594a8..fbd7605a5865 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1500,30 +1500,32 @@ void disk_unblock_events(struct gendisk *disk)
- * 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.
- * 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)
- spin_lock_irqsave(&ev->lock, flags);
+ spin_lock_irq(&ev->lock);
+ ev->clearing |= mask;
if (!ev->block) {
queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
- spin_unlock_irqrestore(&ev->lock, flags);
+ spin_unlock_irq(&ev->lock);
* disk_clear_events - synchronously check, clear and return pending events
@@ -1713,7 +1715,7 @@ static int disk_events_set_dfl_poll_msecs(const char *val,
list_for_each_entry(ev, &disk_events, node)
- disk_check_events(ev->disk);
+ disk_flush_events(ev->disk, 0);