btrfs: introduce a common helper to calculate the size of a bio

We have several call sites doing the same work to calculate the size of
a bio:

	struct bio_vec *bvec;
	u32 bio_size = 0;
	int i;

	bio_for_each_bvec_all(bvec, bio, i)
		bio_size += bvec->bv_len;

We can use a common helper instead of open-coding it everywhere.

This also allows us to constify the @bio_size variables used in all the
call sites.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/misc.h b/fs/btrfs/misc.h
index 40433a86fe49641f174284add6a73f76abcbaacc..694be6d0562a4e407481491dfe459377525e5654 100644 (file)
--- a/fs/btrfs/misc.h
+++ b/fs/btrfs/misc.h
@@ -53,15 +53,22 @@ static inline phys_addr_t bio_iter_phys(const struct bio *bio,
             (paddr = bio_iter_phys((bio), (iter)), 1);                 \
             bio_advance_iter_single((bio), (iter), (blocksize)))
 
-/* Initialize a bvec_iter to the size of the specified bio. */
-static inline struct bvec_iter init_bvec_iter_for_bio(struct bio *bio)
+/* Can only be called on a non-cloned bio. */
+static inline u32 bio_get_size(struct bio *bio)
 {
        struct bio_vec *bvec;
-       u32 bio_size = 0;
+       u32 ret = 0;
        int i;
 
        bio_for_each_bvec_all(bvec, bio, i)
-               bio_size += bvec->bv_len;
+               ret += bvec->bv_len;
+       return ret;
+}
+
+/* Initialize a bvec_iter to the size of the specified bio. */
+static inline struct bvec_iter init_bvec_iter_for_bio(struct bio *bio)
+{
+       const u32 bio_size = bio_get_size(bio);
 
        return (struct bvec_iter) {
                .bi_sector = 0,

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 02105d68accb940edb3256a83eebe626b0d1b94c..aacf5e4eb765cea09c9841009b0f3d00ba6fce67 100644 (file)
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1653,12 +1653,7 @@ static int get_bio_sector_nr(struct btrfs_raid_bio *rbio, struct bio *bio)
 static void rbio_update_error_bitmap(struct btrfs_raid_bio *rbio, struct bio *bio)
 {
        int total_sector_nr = get_bio_sector_nr(rbio, bio);
-       u32 bio_size = 0;
-       struct bio_vec *bvec;
-       int i;
-
-       bio_for_each_bvec_all(bvec, bio, i)
-               bio_size += bvec->bv_len;
+       const u32 bio_size = bio_get_size(bio);
 
        /*
         * Since we can have multiple bios touching the error_bitmap, we cannot
@@ -1666,7 +1661,7 @@ static void rbio_update_error_bitmap(struct btrfs_raid_bio *rbio, struct bio *bi
         *
         * Instead use set_bit() for each bit, as set_bit() itself is atomic.
         */
-       for (i = total_sector_nr; i < total_sector_nr +
+       for (int i = total_sector_nr; i < total_sector_nr +
             (bio_size >> rbio->bioc->fs_info->sectorsize_bits); i++)
                set_bit(i, rbio->error_bitmap);
 }

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index bc94bbc007720c5ead93ac5e0cd4df9a48522adc..0234971894fa30a0129531c1d758b5b443b0976d 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -891,16 +891,11 @@ static void scrub_repair_read_endio(struct btrfs_bio *bbio)
 {
        struct scrub_stripe *stripe = bbio->private;
        struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
-       struct bio_vec *bvec;
        int sector_nr = calc_sector_number(stripe, bio_first_bvec_all(&bbio->bio));
-       u32 bio_size = 0;
-       int i;
+       const u32 bio_size = bio_get_size(&bbio->bio);
 
        ASSERT(sector_nr < stripe->nr_sectors);
 
-       bio_for_each_bvec_all(bvec, &bbio->bio, i)
-               bio_size += bvec->bv_len;
-
        if (bbio->bio.bi_status) {
                scrub_bitmap_set_io_error(stripe, sector_nr,
                                          bio_size >> fs_info->sectorsize_bits);
@@ -1249,15 +1244,11 @@ out:
 static void scrub_read_endio(struct btrfs_bio *bbio)
 {
        struct scrub_stripe *stripe = bbio->private;
-       struct bio_vec *bvec;
        int sector_nr = calc_sector_number(stripe, bio_first_bvec_all(&bbio->bio));
        int num_sectors;
-       u32 bio_size = 0;
-       int i;
+       const u32 bio_size = bio_get_size(&bbio->bio);
 
        ASSERT(sector_nr < stripe->nr_sectors);
-       bio_for_each_bvec_all(bvec, &bbio->bio, i)
-               bio_size += bvec->bv_len;
        num_sectors = bio_size >> stripe->bg->fs_info->sectorsize_bits;
 
        if (bbio->bio.bi_status) {
@@ -1278,13 +1269,8 @@ static void scrub_write_endio(struct btrfs_bio *bbio)
 {
        struct scrub_stripe *stripe = bbio->private;
        struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
-       struct bio_vec *bvec;
        int sector_nr = calc_sector_number(stripe, bio_first_bvec_all(&bbio->bio));
-       u32 bio_size = 0;
-       int i;
-
-       bio_for_each_bvec_all(bvec, &bbio->bio, i)
-               bio_size += bvec->bv_len;
+       const u32 bio_size = bio_get_size(&bbio->bio);
 
        if (bbio->bio.bi_status) {
                unsigned long flags;
@@ -1293,7 +1279,7 @@ static void scrub_write_endio(struct btrfs_bio *bbio)
                bitmap_set(&stripe->write_error_bitmap, sector_nr,
                           bio_size >> fs_info->sectorsize_bits);
                spin_unlock_irqrestore(&stripe->write_error_lock, flags);
-               for (i = 0; i < (bio_size >> fs_info->sectorsize_bits); i++)
+               for (int i = 0; i < (bio_size >> fs_info->sectorsize_bits); i++)
                        btrfs_dev_stat_inc_and_print(stripe->dev,
                                                     BTRFS_DEV_STAT_WRITE_ERRS);
        }