bcache: transfer the sb_page reference to register_{bdev,cache}

Avoid an extra reference count roundtrip by transferring the sb_page
ownership to the lower level register helpers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index fad9c6c..cf2cafe 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1368,8 +1368,6 @@ static int register_bdev(struct cache_sb *sb, struct page *sb_page,
 
        bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1);
        bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page;
-       get_page(sb_page);
-
 
        if (cached_dev_init(dc, sb->block_size << 9))
                goto err;
@@ -2275,7 +2273,6 @@ static int register_cache(struct cache_sb *sb, struct page *sb_page,
 
        bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1);
        bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page;
-       get_page(sb_page);
 
        if (blk_queue_discard(bdev_get_queue(bdev)))
                ca->discard = CACHE_DISCARD(&ca->sb);
@@ -2378,7 +2375,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
        const char *err;
        char *path = NULL;
        struct cache_sb *sb;
-       struct block_device *bdev = NULL;
+       struct block_device *bdev;
        struct page *sb_page;
        ssize_t ret;
 
@@ -2444,10 +2441,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
                ret = register_bdev(sb, sb_page, bdev, dc);
                mutex_unlock(&bch_register_lock);
                /* blkdev_put() will be called in cached_dev_free() */
-               if (ret < 0) {
-                       bdev = NULL;
-                       goto out_put_sb_page;
-               }
+               if (ret < 0)
+                       goto out_free_sb;
        } else {
                struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
 
@@ -2455,13 +2450,10 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
                        goto out_put_sb_page;
 
                /* blkdev_put() will be called in bch_cache_release() */
-               if (register_cache(sb, sb_page, bdev, ca) != 0) {
-                       bdev = NULL;
-                       goto out_put_sb_page;
-               }
+               if (register_cache(sb, sb_page, bdev, ca) != 0)
+                       goto out_free_sb;
        }
 
-       put_page(sb_page);
 done:
        kfree(sb);
        kfree(path);
@@ -2471,8 +2463,7 @@ done:
 out_put_sb_page:
        put_page(sb_page);
 out_blkdev_put:
-       if (bdev)
-               blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+       blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
 out_free_sb:
        kfree(sb);
 out_free_path: