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: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index 9315311..6dfbdde 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -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);

diff --git a/block/blk.h b/block/blk.h
index 10ab7c0..d965cac 100644 (file)
--- a/block/blk.h
+++ b/block/blk.h
@@ -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);

diff --git a/block/genhd.c b/block/genhd.c
index e536d0b..e46de61 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -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