block: use ->bi_bdev for bio based I/O accounting

Rework the I/O accounting for bio based drivers to use ->bi_bdev.  This
means all drivers can now simply use bio_start_io_acct to start
accounting, and it will take partitions into account automatically.  To
end I/O account either bio_end_io_acct can be used if the driver never
remaps I/O to a different device, or bio_end_io_acct_remapped if the
driver did remap the I/O.

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 1c1b97a..9315311 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1321,14 +1321,17 @@ static unsigned long __part_start_io_acct(struct block_device *part,
        return now;
 }
 
-unsigned long part_start_io_acct(struct gendisk *disk, struct block_device **part,
-                                struct bio *bio)
+/**
+ * bio_start_io_acct - start I/O accounting for bio based drivers
+ * @bio:       bio to start account for
+ *
+ * Returns the start time that should be passed back to bio_end_io_acct().
+ */
+unsigned long bio_start_io_acct(struct bio *bio)
 {
-       *part = disk_map_sector_rcu(disk, bio->bi_iter.bi_sector);
-
-       return __part_start_io_acct(*part, bio_sectors(bio), bio_op(bio));
+       return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio), bio_op(bio));
 }
-EXPORT_SYMBOL_GPL(part_start_io_acct);
+EXPORT_SYMBOL_GPL(bio_start_io_acct);
 
 unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
                                 unsigned int op)
@@ -1351,12 +1354,12 @@ static void __part_end_io_acct(struct block_device *part, unsigned int op,
        part_stat_unlock();
 }
 
-void part_end_io_acct(struct block_device *part, struct bio *bio,
-                     unsigned long start_time)
+void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
+               struct block_device *orig_bdev)
 {
-       __part_end_io_acct(part, bio_op(bio), start_time);
+       __part_end_io_acct(orig_bdev, bio_op(bio), start_time);
 }
-EXPORT_SYMBOL_GPL(part_end_io_acct);
+EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
 
 void disk_end_io_acct(struct gendisk *disk, unsigned int op,
                      unsigned long start_time)

diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index dfc35d6..29c2317 100644 (file)
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -475,7 +475,7 @@ struct search {
        unsigned int            read_dirty_data:1;
        unsigned int            cache_missed:1;
 
-       struct block_device     *part;
+       struct block_device     *orig_bdev;
        unsigned long           start_time;
 
        struct btree_op         op;
@@ -670,8 +670,8 @@ static void bio_complete(struct search *s)
 {
        if (s->orig_bio) {
                /* Count on bcache device */
-               part_end_io_acct(s->part, s->orig_bio, s->start_time);
-
+               bio_end_io_acct_remapped(s->orig_bio, s->start_time,
+                                        s->orig_bdev);
                trace_bcache_request_end(s->d, s->orig_bio);
                s->orig_bio->bi_status = s->iop.status;
                bio_endio(s->orig_bio);
@@ -714,7 +714,8 @@ static void search_free(struct closure *cl)
 }
 
 static inline struct search *search_alloc(struct bio *bio,
-                                         struct bcache_device *d)
+               struct bcache_device *d, struct block_device *orig_bdev,
+               unsigned long start_time)
 {
        struct search *s;
 
@@ -732,7 +733,8 @@ static inline struct search *search_alloc(struct bio *bio,
        s->write                = op_is_write(bio_op(bio));
        s->read_dirty_data      = 0;
        /* Count on the bcache device */
-       s->start_time           = part_start_io_acct(d->disk, &s->part, bio);
+       s->orig_bdev            = orig_bdev;
+       s->start_time           = start_time;
        s->iop.c                = d->c;
        s->iop.bio              = NULL;
        s->iop.inode            = d->id;
@@ -1074,7 +1076,7 @@ struct detached_dev_io_private {
        unsigned long           start_time;
        bio_end_io_t            *bi_end_io;
        void                    *bi_private;
-       struct block_device     *part;
+       struct block_device     *orig_bdev;
 };
 
 static void detached_dev_end_io(struct bio *bio)
@@ -1086,7 +1088,7 @@ static void detached_dev_end_io(struct bio *bio)
        bio->bi_private = ddip->bi_private;
 
        /* Count on the bcache device */
-       part_end_io_acct(ddip->part, bio, ddip->start_time);
+       bio_end_io_acct_remapped(bio, ddip->start_time, ddip->orig_bdev);
 
        if (bio->bi_status) {
                struct cached_dev *dc = container_of(ddip->d,
@@ -1099,7 +1101,8 @@ static void detached_dev_end_io(struct bio *bio)
        bio->bi_end_io(bio);
 }
 
-static void detached_dev_do_request(struct bcache_device *d, struct bio *bio)
+static void detached_dev_do_request(struct bcache_device *d, struct bio *bio,
+               struct block_device *orig_bdev, unsigned long start_time)
 {
        struct detached_dev_io_private *ddip;
        struct cached_dev *dc = container_of(d, struct cached_dev, disk);
@@ -1112,7 +1115,8 @@ static void detached_dev_do_request(struct bcache_device *d, struct bio *bio)
        ddip = kzalloc(sizeof(struct detached_dev_io_private), GFP_NOIO);
        ddip->d = d;
        /* Count on the bcache device */
-       ddip->start_time = part_start_io_acct(d->disk, &ddip->part, bio);
+       ddip->orig_bdev = orig_bdev;
+       ddip->start_time = start_time;
        ddip->bi_end_io = bio->bi_end_io;
        ddip->bi_private = bio->bi_private;
        bio->bi_end_io = detached_dev_end_io;
@@ -1168,8 +1172,10 @@ static void quit_max_writeback_rate(struct cache_set *c,
 blk_qc_t cached_dev_submit_bio(struct bio *bio)
 {
        struct search *s;
-       struct bcache_device *d = bio->bi_bdev->bd_disk->private_data;
+       struct block_device *orig_bdev = bio->bi_bdev;
+       struct bcache_device *d = orig_bdev->bd_disk->private_data;
        struct cached_dev *dc = container_of(d, struct cached_dev, disk);
+       unsigned long start_time;
        int rw = bio_data_dir(bio);
 
        if (unlikely((d->c && test_bit(CACHE_SET_IO_DISABLE, &d->c->flags)) ||
@@ -1194,11 +1200,13 @@ blk_qc_t cached_dev_submit_bio(struct bio *bio)
                }
        }
 
+       start_time = bio_start_io_acct(bio);
+
        bio_set_dev(bio, dc->bdev);
        bio->bi_iter.bi_sector += dc->sb.data_offset;
 
        if (cached_dev_get(dc)) {
-               s = search_alloc(bio, d);
+               s = search_alloc(bio, d, orig_bdev, start_time);
                trace_bcache_request_start(s->d, bio);
 
                if (!bio->bi_iter.bi_size) {
@@ -1219,7 +1227,7 @@ blk_qc_t cached_dev_submit_bio(struct bio *bio)
                }
        } else
                /* I/O request sent to backing device */
-               detached_dev_do_request(d, bio);
+               detached_dev_do_request(d, bio, orig_bdev, start_time);
 
        return BLK_QC_T_NONE;
 }
@@ -1283,7 +1291,7 @@ blk_qc_t flash_dev_submit_bio(struct bio *bio)
                return BLK_QC_T_NONE;
        }
 
-       s = search_alloc(bio, d);
+       s = search_alloc(bio, d, bio->bi_bdev, bio_start_io_acct(bio));
        cl = &s->cl;
        bio = &s->bio.bio;
 

diff --git a/drivers/md/md.c b/drivers/md/md.c
index cf06dbb..7d1bb24 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -463,8 +463,8 @@ struct md_io {
        struct mddev *mddev;
        bio_end_io_t *orig_bi_end_io;
        void *orig_bi_private;
+       struct block_device *orig_bi_bdev;
        unsigned long start_time;
-       struct block_device *part;
 };
 
 static void md_end_io(struct bio *bio)
@@ -472,7 +472,7 @@ static void md_end_io(struct bio *bio)
        struct md_io *md_io = bio->bi_private;
        struct mddev *mddev = md_io->mddev;
 
-       part_end_io_acct(md_io->part, bio, md_io->start_time);
+       bio_end_io_acct_remapped(bio, md_io->start_time, md_io->orig_bi_bdev);
 
        bio->bi_end_io = md_io->orig_bi_end_io;
        bio->bi_private = md_io->orig_bi_private;
@@ -514,12 +514,12 @@ static blk_qc_t md_submit_bio(struct bio *bio)
                md_io->mddev = mddev;
                md_io->orig_bi_end_io = bio->bi_end_io;
                md_io->orig_bi_private = bio->bi_private;
+               md_io->orig_bi_bdev = bio->bi_bdev;
 
                bio->bi_end_io = md_end_io;
                bio->bi_private = md_io;
 
-               md_io->start_time = part_start_io_acct(mddev->gendisk,
-                                                      &md_io->part, bio);
+               md_io->start_time = bio_start_io_acct(bio);
        }
 
        /* bio could be mergeable after passing to underlayer */

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b55bd53..4526b9e 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1954,22 +1954,9 @@ unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 void disk_end_io_acct(struct gendisk *disk, unsigned int op,
                unsigned long start_time);
 
-unsigned long part_start_io_acct(struct gendisk *disk,
-               struct block_device **part, struct bio *bio);
-void part_end_io_acct(struct block_device *part, struct bio *bio,
-                     unsigned long start_time);
-
-/**
- * bio_start_io_acct - start I/O accounting for bio based drivers
- * @bio:       bio to start account for
- *
- * Returns the start time that should be passed back to bio_end_io_acct().
- */
-static inline unsigned long bio_start_io_acct(struct bio *bio)
-{
-       return disk_start_io_acct(bio->bi_bdev->bd_disk, bio_sectors(bio),
-                                 bio_op(bio));
-}
+unsigned long bio_start_io_acct(struct bio *bio);
+void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
+               struct block_device *orig_bdev);
 
 /**
  * bio_end_io_acct - end I/O accounting for bio based drivers
@@ -1978,7 +1965,7 @@ static inline unsigned long bio_start_io_acct(struct bio *bio)
  */
 static inline void bio_end_io_acct(struct bio *bio, unsigned long start_time)
 {
-       return disk_end_io_acct(bio->bi_bdev->bd_disk, bio_op(bio), start_time);
+       return bio_end_io_acct_remapped(bio, start_time, bio->bi_bdev);
 }
 
 int bdev_read_only(struct block_device *bdev);