Commit 33a18062 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm bufio: introduce forget_buffer_locked 



Introduce a function forget_buffer_locked that forgets a range of
buffers. It is more efficient than calling forget_buffer in a loop.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 88f878e5

drivers/md/dm-bufio.c

+56 −4
Original line number Diff line number Diff line
@@ -262,6 +262,29 @@ static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) 
	return NULL;

}



static struct dm_buffer *__find_next(struct dm_bufio_client *c, sector_t block)

{

	struct rb_node *n = c->buffer_tree.rb_node;

	struct dm_buffer *b;

	struct dm_buffer *best = NULL;



	while (n) {

		b = container_of(n, struct dm_buffer, node);



		if (b->block == block)

			return b;



		if (block <= b->block) {

			n = n->rb_left;

			best = b;

		} else {

			n = n->rb_right;

		}

	}



	return best;

}



static void __insert(struct dm_bufio_client *c, struct dm_buffer *b)

{

	struct rb_node **new = &c->buffer_tree.rb_node, *parent = NULL;
@@ -1434,6 +1457,14 @@ void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) 
}

EXPORT_SYMBOL_GPL(dm_bufio_release_move);



static void forget_buffer_locked(struct dm_buffer *b)

{

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

		__unlink_buffer(b);

		__free_buffer_wake(b);

	}

}



/*

 * Free the given buffer.

 *
@@ -1447,15 +1478,36 @@ void dm_bufio_forget(struct dm_bufio_client *c, sector_t block) 
	dm_bufio_lock(c);



	b = __find(c, block);

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

		__unlink_buffer(b);

		__free_buffer_wake(b);

	}

	if (b)

		forget_buffer_locked(b);



	dm_bufio_unlock(c);

}

EXPORT_SYMBOL_GPL(dm_bufio_forget);



void dm_bufio_forget_buffers(struct dm_bufio_client *c, sector_t block, sector_t n_blocks)

{

	struct dm_buffer *b;

	sector_t end_block = block + n_blocks;



	while (block < end_block) {

		dm_bufio_lock(c);



		b = __find_next(c, block);

		if (b) {

			block = b->block + 1;

			forget_buffer_locked(b);

		}



		dm_bufio_unlock(c);



		if (!b)

			break;

	}



}

EXPORT_SYMBOL_GPL(dm_bufio_forget_buffers);



void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned n)

{

	c->minimum_buffers = n;

include/linux/dm-bufio.h

+7 −0
Original line number Diff line number Diff line
@@ -136,6 +136,13 @@ void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block); 
 */

void dm_bufio_forget(struct dm_bufio_client *c, sector_t block);



/*

 * Free the given range of buffers.

 * This is just a hint, if the buffer is in use or dirty, this function

 * does nothing.

 */

void dm_bufio_forget_buffers(struct dm_bufio_client *c, sector_t block, sector_t n_blocks);



/*

 * Set the minimum number of buffers before cleanup happens.

 */