linux/block/bdev.c

532  * @holder: holder trying to claim @bdev
533  * @hops: holder ops
535  * Test whether @bdev can be claimed by @holder.
540 static bool bd_may_claim(struct block_device *bdev, void *holder,
549 		 * The same holder can always re-claim.
551 		if (bdev->bd_holder == holder) {
560 	 * If the whole devices holder is set to bd_may_claim, a partition on
572  * @holder: holder trying to claim @bdev
573  * @hops: holder ops.
576  * holder and waits if another claiming is in progress. return, the caller
582 int bd_prepare_to_claim(struct block_device *bdev, void *holder,
587 	if (WARN_ON_ONCE(!holder))
592 	if (!bd_may_claim(bdev, holder, hops)) {
610 	whole->bd_claiming = holder;
616 static void bd_clear_claiming(struct block_device *whole, void *holder)
620 	BUG_ON(whole->bd_claiming != holder);
628  * @holder: holder that has claimed @bdev
629  * @hops: block device holder operations
632  * open by the holder and wake up all waiters for exclusive open to finish.
634 static void bd_finish_claiming(struct block_device *bdev, void *holder,
640 	BUG_ON(!bd_may_claim(bdev, holder, hops));
643 	 * and bd_holder will be set to bd_may_claim before being set to holder
649 	bdev->bd_holder = holder;
652 	bd_clear_claiming(whole, holder);
659  * @holder: holder that has claimed @bdev
665 void bd_abort_claiming(struct block_device *bdev, void *holder)
668 	bd_clear_claiming(bdev_whole(bdev), holder);
673 static void bd_end_claim(struct block_device *bdev, void *holder)
679 	 * Release a claim on the device.  The holder fields are protected with
683 	WARN_ON_ONCE(bdev->bd_holder != holder);
699 	 * If this was the last claim, remove holder link and unblock evpoll if
700 	 * it was a write holder.
782 int bdev_permission(dev_t dev, blk_mode_t mode, void *holder)
794 	if (mode & BLK_OPEN_RESTRICT_WRITES && !holder)
801 	if (WARN_ON_ONCE(IS_ERR(holder)))
913  * @holder: exclusive holder identifier
914  * @hops: holder operations
917  * Open the block device. If @holder is not %NULL, the block device is opened
918  * with exclusive access.  Exclusive opens may nest for the same @holder.
926 int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
933 	if (holder) {
935 		ret = bd_prepare_to_claim(bdev, holder, hops);
961 	if (holder) {
962 		bd_finish_claiming(bdev, holder, hops);
966 		 * holder makes the write_holder state stick until all are
991 	bdev_file->private_data = holder;
997 	if (holder)
998 		bd_abort_claiming(bdev, holder);
1034 struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
1042 	ret = bdev_permission(dev, mode, holder);
1059 	ret = bdev_open(bdev, mode, holder, hops, bdev_file);
1071 				    void *holder,
1082 	file = bdev_file_open_by_dev(dev, mode, holder, hops);
1097 	void *holder = bdev_file->private_data;
1101 	if (WARN_ON_ONCE(IS_ERR_OR_NULL(holder)))
1105 		bd_end_claim(bdev, holder);
1111 	void *holder = bdev_file->private_data;
1115 	if (IS_ERR(holder))
1131 	if (holder)