diff options
author | Tejun Heo <tj@kernel.org> | 2011-07-01 16:17:47 +0200 |
---|---|---|
committer | Jens Axboe <jaxboe@fusionio.com> | 2011-07-01 16:17:47 +0200 |
commit | 85ef06d1d252f6a2e73b678591ab71caad4667bb (patch) | |
tree | dc5cbc4f2e54f5b5b3f8653a595799e5fe0f2f18 /block | |
parent | 04bf7869ca0fd12009aee301cac2264a36df4d98 (diff) | |
download | lwn-85ef06d1d252f6a2e73b678591ab71caad4667bb.tar.gz lwn-85ef06d1d252f6a2e73b678591ab71caad4667bb.zip |
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>
Diffstat (limited to 'block')
-rw-r--r-- | block/genhd.c | 22 |
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. * * 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_msecs(const char *val, 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); |