[PATCH -next RFC 10/14] 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     | 17 +++++++++++------
 fs/erofs/internal.h |  1 +
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index c98aeda8abb2..b9d2c90f9b22 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -32,8 +32,8 @@ 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;
+	u8 blkbits = buf->inode ? buf->inode->i_blkbits : block_bits(buf->bdev);
+	erofs_off_t offset = (erofs_off_t)blkaddr << blkbits;
 	pgoff_t index = offset >> PAGE_SHIFT;
 	struct page *page = buf->page;
 	struct folio *folio;
@@ -43,7 +43,9 @@ 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, index);
 		memalloc_nofs_restore(nofs_flag);
 		if (IS_ERR(folio))
 			return folio;
@@ -67,10 +69,13 @@ 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;
+	} else {
+		buf->inode = NULL;
+		buf->bdev = sb->s_bdev;
+	}
 }
 
 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..a68b0924c052 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -224,6 +224,7 @@ enum erofs_kmap_type {
 
 struct erofs_buf {
 	struct inode *inode;
+	struct block_device *bdev;
 	struct page *page;
 	void *base;
 	enum erofs_kmap_type kmap_type;
-- 
2.39.2