btrfs: cleanup: use for() loop in btrfs_map_bio()

for() is obviously better in these code block, and remove noused
init-value to reduce about 6 bytes binary size.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 30c6074f3d00e07c5b8baf714205ae6a864d17ef..d7d1dde5f2ff38127b9b228941aa11f833d9c837 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5820,8 +5820,8 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
        u64 length = 0;
        u64 map_length;
        int ret;
-       int dev_nr = 0;
-       int total_devs = 1;
+       int dev_nr;
+       int total_devs;
        struct btrfs_bio *bbio = NULL;
 
        length = bio->bi_iter.bi_size;
@@ -5862,11 +5862,10 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                BUG();
        }
 
-       while (dev_nr < total_devs) {
+       for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
                dev = bbio->stripes[dev_nr].dev;
                if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
                        bbio_error(bbio, first_bio, logical);
-                       dev_nr++;
                        continue;
                }
 
@@ -5879,7 +5878,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                        ret = breakup_stripe_bio(root, bbio, first_bio, dev,
                                                 dev_nr, rw, async_submit);
                        BUG_ON(ret);
-                       dev_nr++;
                        continue;
                }
 
@@ -5894,7 +5892,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                submit_stripe_bio(root, bbio, bio,
                                  bbio->stripes[dev_nr].physical, dev_nr, rw,
                                  async_submit);
-               dev_nr++;
        }
        btrfs_bio_counter_dec(root->fs_info);
        return 0;