block: change exported IO accounting interface from gendisk to bdev

Export IO accounting interfaces in terms of block_device now that
gendisk has become more internal to block core.

Rename __part_{start,end}_io_acct's first argument from part to bdev.
Rename __part_{start,end}_io_acct to bdev_{start,end}_io_acct and
export them.  Remove disk_{start,end}_io_acct and update caller (zram)
to use bdev_{start,end}_io_acct.

DM can now be updated to use bdev_{start,end}_io_acct.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20220418022733.56168-2-snitzer@kernel.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-core.c

@@ -1022,21 +1022,22 @@ void update_io_ticks(struct block_device *part, unsigned long now, bool end)
 	}
 }
 
-static unsigned long __part_start_io_acct(struct block_device *part,
-					  unsigned int sectors, unsigned int op,
-					  unsigned long start_time)
+unsigned long bdev_start_io_acct(struct block_device *bdev,
+				 unsigned int sectors, unsigned int op,
+				 unsigned long start_time)
 {
 	const int sgrp = op_stat_group(op);
 
 	part_stat_lock();
-	update_io_ticks(part, start_time, false);
-	part_stat_inc(part, ios[sgrp]);
-	part_stat_add(part, sectors[sgrp], sectors);
-	part_stat_local_inc(part, in_flight[op_is_write(op)]);
+	update_io_ticks(bdev, start_time, false);
+	part_stat_inc(bdev, ios[sgrp]);
+	part_stat_add(bdev, sectors[sgrp], sectors);
+	part_stat_local_inc(bdev, in_flight[op_is_write(op)]);
 	part_stat_unlock();
 
 	return start_time;
 }
+EXPORT_SYMBOL(bdev_start_io_acct);
 
 /**
  * bio_start_io_acct_time - start I/O accounting for bio based drivers
@@ -1045,8 +1046,8 @@ static unsigned long __part_start_io_acct(struct block_device *part,
  */
 void bio_start_io_acct_time(struct bio *bio, unsigned long start_time)
 {
-	__part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
-			     bio_op(bio), start_time);
+	bdev_start_io_acct(bio->bi_bdev, bio_sectors(bio),
+			   bio_op(bio), start_time);
 }
 EXPORT_SYMBOL_GPL(bio_start_io_acct_time);
 
@@ -1058,46 +1059,33 @@ EXPORT_SYMBOL_GPL(bio_start_io_acct_time);
  */
 unsigned long bio_start_io_acct(struct bio *bio)
 {
-	return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio),
-				    bio_op(bio), jiffies);
+	return bdev_start_io_acct(bio->bi_bdev, bio_sectors(bio),
+				  bio_op(bio), jiffies);
 }
 EXPORT_SYMBOL_GPL(bio_start_io_acct);
 
-unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
-				 unsigned int op)
-{
-	return __part_start_io_acct(disk->part0, sectors, op, jiffies);
-}
-EXPORT_SYMBOL(disk_start_io_acct);
-
-static void __part_end_io_acct(struct block_device *part, unsigned int op,
-			       unsigned long start_time)
+void bdev_end_io_acct(struct block_device *bdev, unsigned int op,
+		      unsigned long start_time)
 {
 	const int sgrp = op_stat_group(op);
 	unsigned long now = READ_ONCE(jiffies);
 	unsigned long duration = now - start_time;
 
 	part_stat_lock();
-	update_io_ticks(part, now, true);
-	part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
-	part_stat_local_dec(part, in_flight[op_is_write(op)]);
+	update_io_ticks(bdev, now, true);
+	part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration));
+	part_stat_local_dec(bdev, in_flight[op_is_write(op)]);
 	part_stat_unlock();
 }
+EXPORT_SYMBOL(bdev_end_io_acct);
 
 void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
-		struct block_device *orig_bdev)
+			      struct block_device *orig_bdev)
 {
-	__part_end_io_acct(orig_bdev, bio_op(bio), start_time);
+	bdev_end_io_acct(orig_bdev, bio_op(bio), start_time);
 }
 EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
 
-void disk_end_io_acct(struct gendisk *disk, unsigned int op,
-		      unsigned long start_time)
-{
-	__part_end_io_acct(disk->part0, op, start_time);
-}
-EXPORT_SYMBOL(disk_end_io_acct);
-
 /**
  * blk_lld_busy - Check if underlying low-level drivers of a device are busy
  * @q : the queue of the device being checked

drivers/block/zram/zram_drv.c

@@ -1675,9 +1675,10 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
 	bv.bv_len = PAGE_SIZE;
 	bv.bv_offset = 0;
 
-	start_time = disk_start_io_acct(bdev->bd_disk, SECTORS_PER_PAGE, op);
+	start_time = bdev_start_io_acct(bdev->bd_disk->part0,
+			SECTORS_PER_PAGE, op, jiffies);
 	ret = zram_bvec_rw(zram, &bv, index, offset, op, NULL);
-	disk_end_io_acct(bdev->bd_disk, op, start_time);
+	bdev_end_io_acct(bdev->bd_disk->part0, op, start_time);
 out:
 	/*
 	 * If I/O fails, just return error(ie, non-zero) without

include/linux/blkdev.h

@@ -1463,9 +1463,10 @@ static inline void blk_wake_io_task(struct task_struct *waiter)
 		wake_up_process(waiter);
 }
 
-unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
-		unsigned int op);
-void disk_end_io_acct(struct gendisk *disk, unsigned int op,
+unsigned long bdev_start_io_acct(struct block_device *bdev,
+				 unsigned int sectors, unsigned int op,
+				 unsigned long start_time);
+void bdev_end_io_acct(struct block_device *bdev, unsigned int op,
 		unsigned long start_time);
 
 void bio_start_io_acct_time(struct bio *bio, unsigned long start_time);