[PATCH 07/17] bcache: return a pointer to the on-disk sb from read_super

colyli
2020-01-23T17:02:45Z

From: Christoph Hellwig <hch@lst.de>

Returning the properly typed actual data structure insteaf of the
containing struct page will save the callers some work going
forward.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/bcache/super.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index cf2cafef381f..b30e4c6011d2 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -60,7 +60,7 @@ struct workqueue_struct *bch_journal_wq;
/* Superblock */

static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
- struct page **res)
+ struct cache_sb_disk **res)
{
const char *err;
struct cache_sb_disk *s;
@@ -191,7 +191,7 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
err = NULL;

get_page(bh->b_page);
- *res = bh->b_page;
+ *res = s;
err:
put_bh(bh);
return err;
@@ -1353,7 +1353,7 @@ static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)

/* Cached device - bcache superblock */

-static int register_bdev(struct cache_sb *sb, struct page *sb_page,
+static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
struct block_device *bdev,
struct cached_dev *dc)
{
@@ -1367,7 +1367,7 @@ static int register_bdev(struct cache_sb *sb, struct page *sb_page,
dc->bdev->bd_holder = dc;

bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1);
- bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page;
+ bio_first_bvec_all(&dc->sb_bio)->bv_page = virt_to_page(sb_disk);

if (cached_dev_init(dc, sb->block_size << 9))
goto err;
@@ -2260,7 +2260,7 @@ static int cache_alloc(struct cache *ca)
return ret;
}

-static int register_cache(struct cache_sb *sb, struct page *sb_page,
+static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
struct block_device *bdev, struct cache *ca)
{
const char *err = NULL; /* must be set for any error case */
@@ -2272,7 +2272,7 @@ static int register_cache(struct cache_sb *sb, struct page *sb_page,
ca->bdev->bd_holder = ca;

bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1);
- bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page;
+ bio_first_bvec_all(&ca->sb_bio)->bv_page = virt_to_page(sb_disk);

if (blk_queue_discard(bdev_get_queue(bdev)))
ca->discard = CACHE_DISCARD(&ca->sb);
@@ -2375,8 +2375,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
const char *err;
char *path = NULL;
struct cache_sb *sb;
+ struct cache_sb_disk *sb_disk;
struct block_device *bdev;
- struct page *sb_page;
ssize_t ret;

ret = -EBUSY;
@@ -2426,7 +2426,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
if (set_blocksize(bdev, 4096))
goto out_blkdev_put;

- err = read_super(sb, bdev, &sb_page);
+ err = read_super(sb, bdev, &sb_disk);
if (err)
goto out_blkdev_put;

@@ -2438,7 +2438,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
goto out_put_sb_page;

mutex_lock(&bch_register_lock);
- ret = register_bdev(sb, sb_page, bdev, dc);
+ ret = register_bdev(sb, sb_disk, bdev, dc);
mutex_unlock(&bch_register_lock);
/* blkdev_put() will be called in cached_dev_free() */
if (ret < 0)
@@ -2450,7 +2450,7 @@ 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)
+ if (register_cache(sb, sb_disk, bdev, ca) != 0)
goto out_free_sb;
}

@@ -2461,7 +2461,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
return size;

out_put_sb_page:
- put_page(sb_page);
+ put_page(virt_to_page(sb_disk));
out_blkdev_put:
blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
out_free_sb:
--
2.16.4