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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>
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parent
04bf7869ca
commit
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3 changed files with 27 additions and 20 deletions
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@ -1500,30 +1500,32 @@ void disk_unblock_events(struct gendisk *disk)
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}
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}
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/**
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/**
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* disk_check_events - schedule immediate event checking
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* disk_flush_events - schedule immediate event checking and flushing
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* @disk: disk to check events for
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* @disk: disk to check and flush events for
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* @mask: events to flush
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*
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*
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* Schedule immediate event checking on @disk if not blocked.
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* Schedule immediate event checking on @disk if not blocked. Events in
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* @mask are scheduled to be cleared from the driver. Note that this
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* doesn't clear the events from @disk->ev.
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*
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*
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* CONTEXT:
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* CONTEXT:
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* Don't care. Safe to call from irq context.
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* If @mask is non-zero must be called with bdev->bd_mutex held.
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*/
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*/
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void disk_check_events(struct gendisk *disk)
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void disk_flush_events(struct gendisk *disk, unsigned int mask)
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{
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{
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struct disk_events *ev = disk->ev;
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struct disk_events *ev = disk->ev;
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unsigned long flags;
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if (!ev)
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if (!ev)
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return;
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return;
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spin_lock_irqsave(&ev->lock, flags);
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spin_lock_irq(&ev->lock);
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ev->clearing |= mask;
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if (!ev->block) {
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if (!ev->block) {
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cancel_delayed_work(&ev->dwork);
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cancel_delayed_work(&ev->dwork);
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queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
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queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
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}
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}
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spin_unlock_irqrestore(&ev->lock, flags);
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spin_unlock_irq(&ev->lock);
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}
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}
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EXPORT_SYMBOL_GPL(disk_check_events);
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/**
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/**
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* disk_clear_events - synchronously check, clear and return pending events
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* disk_clear_events - synchronously check, clear and return pending events
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@ -1713,7 +1715,7 @@ static int disk_events_set_dfl_poll_msecs(const char *val,
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mutex_lock(&disk_events_mutex);
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mutex_lock(&disk_events_mutex);
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list_for_each_entry(ev, &disk_events, node)
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list_for_each_entry(ev, &disk_events, node)
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disk_check_events(ev->disk);
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disk_flush_events(ev->disk, 0);
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mutex_unlock(&disk_events_mutex);
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mutex_unlock(&disk_events_mutex);
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@ -1447,6 +1447,8 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
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int blkdev_put(struct block_device *bdev, fmode_t mode)
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int blkdev_put(struct block_device *bdev, fmode_t mode)
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{
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{
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mutex_lock(&bdev->bd_mutex);
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if (mode & FMODE_EXCL) {
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if (mode & FMODE_EXCL) {
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bool bdev_free;
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bool bdev_free;
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@ -1455,7 +1457,6 @@ int blkdev_put(struct block_device *bdev, fmode_t mode)
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* are protected with bdev_lock. bd_mutex is to
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* are protected with bdev_lock. bd_mutex is to
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* synchronize disk_holder unlinking.
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* synchronize disk_holder unlinking.
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*/
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*/
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mutex_lock(&bdev->bd_mutex);
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spin_lock(&bdev_lock);
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spin_lock(&bdev_lock);
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WARN_ON_ONCE(--bdev->bd_holders < 0);
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WARN_ON_ONCE(--bdev->bd_holders < 0);
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@ -1473,17 +1474,21 @@ int blkdev_put(struct block_device *bdev, fmode_t mode)
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* If this was the last claim, remove holder link and
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* If this was the last claim, remove holder link and
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* unblock evpoll if it was a write holder.
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* unblock evpoll if it was a write holder.
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*/
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*/
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if (bdev_free) {
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if (bdev_free && bdev->bd_write_holder) {
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if (bdev->bd_write_holder) {
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disk_unblock_events(bdev->bd_disk);
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disk_unblock_events(bdev->bd_disk);
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bdev->bd_write_holder = false;
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disk_check_events(bdev->bd_disk);
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bdev->bd_write_holder = false;
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}
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}
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}
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mutex_unlock(&bdev->bd_mutex);
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}
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}
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/*
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* Trigger event checking and tell drivers to flush MEDIA_CHANGE
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* event. This is to ensure detection of media removal commanded
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* from userland - e.g. eject(1).
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*/
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disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE);
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mutex_unlock(&bdev->bd_mutex);
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return __blkdev_put(bdev, mode, 0);
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return __blkdev_put(bdev, mode, 0);
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}
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}
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EXPORT_SYMBOL(blkdev_put);
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EXPORT_SYMBOL(blkdev_put);
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@ -420,7 +420,7 @@ static inline int get_disk_ro(struct gendisk *disk)
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extern void disk_block_events(struct gendisk *disk);
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extern void disk_block_events(struct gendisk *disk);
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extern void disk_unblock_events(struct gendisk *disk);
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extern void disk_unblock_events(struct gendisk *disk);
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extern void disk_check_events(struct gendisk *disk);
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extern void disk_flush_events(struct gendisk *disk, unsigned int mask);
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extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
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extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
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/* drivers/char/random.c */
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/* drivers/char/random.c */
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