[PATCH RFC v2 for-6.8/block 11/18] erofs: use bdev api

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

Avoid to access bd_inode directly, prepare to remove bd_inode from
block_devcie.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 fs/erofs/data.c     | 18 ++++++++++++------
 fs/erofs/internal.h |  2 ++
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index c98aeda8abb2..8cf3618190ab 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -32,8 +32,7 @@ void erofs_put_metabuf(struct erofs_buf *buf)
 void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
                  enum erofs_kmap_type type)
 {
-       struct inode *inode = buf->inode;
-       erofs_off_t offset = (erofs_off_t)blkaddr << inode->i_blkbits;
+       erofs_off_t offset = (erofs_off_t)blkaddr << buf->blkszbits;
        pgoff_t index = offset >> PAGE_SHIFT;
        struct page *page = buf->page;
        struct folio *folio;
@@ -43,7 +42,9 @@ void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
                erofs_put_metabuf(buf);
 
                nofs_flag = memalloc_nofs_save();
-               folio = read_cache_folio(inode->i_mapping, index, NULL, NULL);
+               folio = buf->inode ?
+                       read_mapping_folio(buf->inode->i_mapping, index, NULL) :
+                       bdev_read_folio(buf->bdev, offset);
                memalloc_nofs_restore(nofs_flag);
                if (IS_ERR(folio))
                        return folio;
@@ -67,10 +68,15 @@ void *erofs_bread(struct erofs_buf *buf, erofs_blk_t 
blkaddr,
 
 void erofs_init_metabuf(struct erofs_buf *buf, struct super_block *sb)
 {
-       if (erofs_is_fscache_mode(sb))
+       if (erofs_is_fscache_mode(sb)) {
                buf->inode = EROFS_SB(sb)->s_fscache->inode;
-       else
-               buf->inode = sb->s_bdev->bd_inode;
+               buf->bdev = NULL;
+               buf->blkszbits = buf->inode->i_blkbits;
+       } else {
+               buf->inode = NULL;
+               buf->bdev = sb->s_bdev;
+               buf->blkszbits = EROFS_SB(sb)->blkszbits;
+       }
 }
 
 void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index b0409badb017..c9206351b485 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -224,8 +224,10 @@ enum erofs_kmap_type {
 
 struct erofs_buf {
        struct inode *inode;
+       struct block_device *bdev;
        struct page *page;
        void *base;
+       u8 blkszbits;
        enum erofs_kmap_type kmap_type;
 };
 #define __EROFS_BUF_INITIALIZER        ((struct erofs_buf){ .page = NULL })
-- 
2.39.2