linux-master/block/bdev.c

464  * @holder: holder trying to claim @bdev
465  * @hops: holder ops
467  * Test whether @bdev can be claimed by @holder.
472 static bool bd_may_claim(struct block_device *bdev, void *holder,
481 		 * The same holder can always re-claim.
483 		if (bdev->bd_holder == holder) {
492 	 * If the whole devices holder is set to bd_may_claim, a partition on
504  * @holder: holder trying to claim @bdev
505  * @hops: holder ops.
508  * holder and waits if another claiming is in progress. return, the caller
514 int bd_prepare_to_claim(struct block_device *bdev, void *holder,
519 	if (WARN_ON_ONCE(!holder))
524 	if (!bd_may_claim(bdev, holder, hops)) {
542 	whole->bd_claiming = holder;
548 static void bd_clear_claiming(struct block_device *whole, void *holder)
552 	BUG_ON(whole->bd_claiming != holder);
560  * @holder: holder that has claimed @bdev
561  * @hops: block device holder operations
564  * open by the holder and wake up all waiters for exclusive open to finish.
566 static void bd_finish_claiming(struct block_device *bdev, void *holder,
572 	BUG_ON(!bd_may_claim(bdev, holder, hops));
575 	 * and bd_holder will be set to bd_may_claim before being set to holder
581 	bdev->bd_holder = holder;
584 	bd_clear_claiming(whole, holder);
591  * @holder: holder that has claimed @bdev
597 void bd_abort_claiming(struct block_device *bdev, void *holder)
600 	bd_clear_claiming(bdev_whole(bdev), holder);
605 static void bd_end_claim(struct block_device *bdev, void *holder)
611 	 * Release a claim on the device.  The holder fields are protected with
615 	WARN_ON_ONCE(bdev->bd_holder != holder);
631 	 * If this was the last claim, remove holder link and unblock evpoll if
632 	 * it was a write holder.
714 int bdev_permission(dev_t dev, blk_mode_t mode, void *holder)
726 	if (mode & BLK_OPEN_RESTRICT_WRITES && !holder)
733 	if (WARN_ON_ONCE(IS_ERR(holder)))
845  * @holder: exclusive holder identifier
846  * @hops: holder operations
849  * Open the block device. If @holder is not %NULL, the block device is opened
850  * with exclusive access.  Exclusive opens may nest for the same @holder.
858 int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
865 	if (holder) {
867 		ret = bd_prepare_to_claim(bdev, holder, hops);
893 	if (holder) {
894 		bd_finish_claiming(bdev, holder, hops);
898 		 * holder makes the write_holder state stick until all are
922 	bdev_file->private_data = holder;
928 	if (holder)
929 		bd_abort_claiming(bdev, holder);
965 struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
973 	ret = bdev_permission(dev, mode, holder);
990 	ret = bdev_open(bdev, mode, holder, hops, bdev_file);
1002 				    void *holder,
1013 	file = bdev_file_open_by_dev(dev, mode, holder, hops);
1028 	void *holder = bdev_file->private_data;
1032 	if (WARN_ON_ONCE(IS_ERR_OR_NULL(holder)))
1036 		bd_end_claim(bdev, holder);
1042 	void *holder = bdev_file->private_data;
1046 	if (IS_ERR(holder))
1062 	if (holder)