dm bufio: delete unused and inefficient dm_bufio_discard_buffers

}

EXPORT_SYMBOL_GPL(dm_bufio_issue_discard);

/*

 * Free the specified range of buffers. If a buffer is held by other process, it

 * is not freed. If a buffer is dirty, it is discarded without writeback.

 * Finally, send the discard request to the device.

 */

int dm_bufio_discard_buffers(struct dm_bufio_client *c, sector_t block, sector_t count)

{

	sector_t i;

	for (i = block; i < block + count; i++) {

		struct dm_buffer *b;

		dm_bufio_lock(c);

		b = __find(c, i);

		if (b && likely(!b->hold_count)) {

			wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE);

			wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);

			__unlink_buffer(b);

			__free_buffer_wake(b);

		}

		dm_bufio_unlock(c);

	}

	return dm_bufio_issue_discard(c, block, count);

}

EXPORT_SYMBOL_GPL(dm_bufio_discard_buffers);

/*

 * We first delete any other buffer that may be at that new location.

 *

 */

int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t count);

/*

 * Free the specified range of buffers. If a buffer is held by other process, it

 * is not freed. If a buffer is dirty, it is discarded without writeback.

 * Finally, send the discard request to the device.

 */

int dm_bufio_discard_buffers(struct dm_bufio_client *c, sector_t block, sector_t count);

/*

 * Like dm_bufio_release but also move the buffer to the new

 * block. dm_bufio_write_dirty_buffers is needed to commit the new block.