block: introduce part_[begin|end]_io_acct

These functions can be used to enable iostat for partitions on devices
like md, bcache.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index 093649b..ca3f0f0 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1324,10 +1324,9 @@ void blk_account_io_start(struct request *rq)
        part_stat_unlock();
 }
 
-unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
-               unsigned int op)
+static unsigned long __part_start_io_acct(struct hd_struct *part,
+                                         unsigned int sectors, unsigned int op)
 {
-       struct hd_struct *part = &disk->part0;
        const int sgrp = op_stat_group(op);
        unsigned long now = READ_ONCE(jiffies);
 
@@ -1340,12 +1339,26 @@ unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 
        return now;
 }
+
+unsigned long part_start_io_acct(struct gendisk *disk, struct hd_struct **part,
+                                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));
+}
+EXPORT_SYMBOL_GPL(part_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);
+}
 EXPORT_SYMBOL(disk_start_io_acct);
 
-void disk_end_io_acct(struct gendisk *disk, unsigned int op,
-               unsigned long start_time)
+static void __part_end_io_acct(struct hd_struct *part, unsigned int op,
+                              unsigned long start_time)
 {
-       struct hd_struct *part = &disk->part0;
        const int sgrp = op_stat_group(op);
        unsigned long now = READ_ONCE(jiffies);
        unsigned long duration = now - start_time;
@@ -1356,6 +1369,20 @@ void disk_end_io_acct(struct gendisk *disk, unsigned int op,
        part_stat_local_dec(part, in_flight[op_is_write(op)]);
        part_stat_unlock();
 }
+
+void part_end_io_acct(struct hd_struct *part, struct bio *bio,
+                     unsigned long start_time)
+{
+       __part_end_io_acct(part, bio_op(bio), start_time);
+       hd_struct_put(part);
+}
+EXPORT_SYMBOL_GPL(part_end_io_acct);
+
+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);
 
 /*

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 37ec5a7..5bd96fb 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1933,6 +1933,11 @@ 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 hd_struct **part,
+                                struct bio *bio);
+void part_end_io_acct(struct hd_struct *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