[PATCH v2 10/24] ext4: add EXT4_LBLK_TO_PG and EXT4_PG_TO_LBLK for block/page conversion

[libaokun@huaweicloud.com]

From: Baokun Li <libaokun1@huawei.com>

As BS > PS support is coming, all block number to page index (and
vice-versa) conversions must now go via bytes. Added EXT4_LBLK_TO_PG()
and EXT4_PG_TO_LBLK() macros to simplify these conversions and handle
both BS <= PS and BS > PS scenarios cleanly.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/ext4/ext4.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index c00ce6db69f0..4bc0b2b7288a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -370,6 +370,12 @@ struct ext4_io_submit {
 	(round_up((offset), i_blocksize(inode)) >> (inode)->i_blkbits)
 #define EXT4_LBLK_TO_B(inode, lblk) ((loff_t)(lblk) << (inode)->i_blkbits)
 
+/* Translate a block number to a page index */
+#define EXT4_LBLK_TO_PG(inode, lblk)	(EXT4_LBLK_TO_B((inode), (lblk)) >> \
+					 PAGE_SHIFT)
+/* Translate a page index to a block number */
+#define EXT4_PG_TO_LBLK(inode, pnum)	(((loff_t)(pnum) << PAGE_SHIFT) >> \
+					 (inode)->i_blkbits)
 /* Translate a block number to a cluster number */
 #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
 /* Translate a cluster number to a block number */
-- 
2.46.1