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 <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/block/genhd.c b/block/genhd.c
index 82d97c3..fbd7605 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1500,30 +1500,32 @@
}
/**
- * 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 @@
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);