Commit 0b6e522c authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-mq: use ->bi_bdev for I/O accounting 



Remove the reverse map from a sector to a partition for I/O accounting by
simply using ->bi_bdev.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 99dfc43e

block/blk-core.c

+5 −1
Original line number Diff line number Diff line
@@ -1298,7 +1298,11 @@ void blk_account_io_start(struct request *rq) 
	if (!blk_do_io_stat(rq))

		return;



	rq->part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));

	/* passthrough requests can hold bios that do not have ->bi_bdev set */

	if (rq->bio && rq->bio->bi_bdev)

		rq->part = rq->bio->bi_bdev;

	else

		rq->part = rq->rq_disk->part0;



	part_stat_lock();

	update_io_ticks(rq->part, jiffies, false);

block/blk.h

+0 −2
Original line number Diff line number Diff line
@@ -333,8 +333,6 @@ void blk_queue_free_zone_bitmaps(struct request_queue *q); 
static inline void blk_queue_free_zone_bitmaps(struct request_queue *q) {}

#endif



struct block_device *disk_map_sector_rcu(struct gendisk *disk, sector_t sector);



int blk_alloc_devt(struct block_device *part, dev_t *devt);

void blk_free_devt(dev_t devt);

char *disk_name(struct gendisk *hd, int partno, char *buf);

block/genhd.c

+0 −48
Original line number Diff line number Diff line
@@ -285,54 +285,6 @@ void disk_part_iter_exit(struct disk_part_iter *piter) 
}

EXPORT_SYMBOL_GPL(disk_part_iter_exit);



static inline int sector_in_part(struct block_device *part, sector_t sector)

{

	return part->bd_start_sect <= sector &&

		sector < part->bd_start_sect + bdev_nr_sectors(part);

}



/**

 * disk_map_sector_rcu - map sector to partition

 * @disk: gendisk of interest

 * @sector: sector to map

 *

 * Find out which partition @sector maps to on @disk.  This is

 * primarily used for stats accounting.

 *

 * CONTEXT:

 * RCU read locked.

 *

 * RETURNS:

 * Found partition on success, part0 is returned if no partition matches

 * or the matched partition is being deleted.

 */

struct block_device *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)

{

	struct disk_part_tbl *ptbl;

	struct block_device *part;

	int i;



	rcu_read_lock();

	ptbl = rcu_dereference(disk->part_tbl);



	part = rcu_dereference(ptbl->last_lookup);

	if (part && sector_in_part(part, sector))

		goto out_unlock;



	for (i = 1; i < ptbl->len; i++) {

		part = rcu_dereference(ptbl->part[i]);

		if (part && sector_in_part(part, sector)) {

			rcu_assign_pointer(ptbl->last_lookup, part);

			goto out_unlock;

		}

	}



	part = disk->part0;

out_unlock:

	rcu_read_unlock();

	return part;

}



/**

 * disk_has_partitions

 * @disk: gendisk of interest