[PATCH v1 1/6] exfat: remove call ilog2() from exfat_readdir()

From: Yuezhang.Mo@xxxxxxxx
Date: Mon Dec 05 2022 - 00:12:27 EST


There is no need to call ilog2() for the conversions between
cluster and dentry in exfat_readdir(), because these conversions
can be replaced with EXFAT_DEN_TO_CLU()/EXFAT_CLU_TO_DEN().

Code refinement, no functional changes.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Reviewed-by: Andy Wu <Andy.Wu@xxxxxxxx>
Reviewed-by: Aoyama Wataru <wataru.aoyama@xxxxxxxx>
---
fs/exfat/dir.c | 9 ++++-----
fs/exfat/exfat_fs.h | 10 ++++++++--
2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index c05493fc9124..397ea2d98848 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -61,7 +61,7 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
/* read a directory entry from the opened directory */
static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
{
- int i, dentries_per_clu, dentries_per_clu_bits = 0, num_ext;
+ int i, dentries_per_clu, num_ext;
unsigned int type, clu_offset, max_dentries;
struct exfat_chain dir, clu;
struct exfat_uni_name uni_name;
@@ -83,11 +83,10 @@ static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_ent
EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);

dentries_per_clu = sbi->dentries_per_clu;
- dentries_per_clu_bits = ilog2(dentries_per_clu);
max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
- (u64)sbi->num_clusters << dentries_per_clu_bits);
+ (u64)EXFAT_CLU_TO_DEN(sbi->num_clusters, sbi));

- clu_offset = dentry >> dentries_per_clu_bits;
+ clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
exfat_chain_dup(&clu, &dir);

if (clu.flags == ALLOC_NO_FAT_CHAIN) {
@@ -162,7 +161,7 @@ static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_ent
dir_entry->entry = dentry;
brelse(bh);

- ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
+ ei->hint_bmap.off = EXFAT_DEN_TO_CLU(dentry, sbi);
ei->hint_bmap.clu = clu.dir;

*cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 324acc57d029..37e8af8042aa 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -101,11 +101,17 @@ enum {
/*
* helpers for block size to dentry size conversion.
*/
-#define EXFAT_B_TO_DEN_IDX(b, sbi) \
- ((b) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
#define EXFAT_B_TO_DEN(b) ((b) >> DENTRY_SIZE_BITS)
#define EXFAT_DEN_TO_B(b) ((b) << DENTRY_SIZE_BITS)

+/*
+ * helpers for cluster size to dentry size conversion.
+ */
+#define EXFAT_CLU_TO_DEN(clu, sbi) \
+ ((clu) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
+#define EXFAT_DEN_TO_CLU(dentry, sbi) \
+ ((dentry) >> ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
+
/*
* helpers for fat entry.
*/
--
2.25.1