Remove switch statement from ufs_set_de_type function in fs/ufs/util.h
header and replace with simple assignment. For each case, S_IFx >> 12
is equal to DT_x, so in valid cases (mode & S_IFMT) >> 12 should give
us the correct file type. This is verified at compile-time with
BUILD_BUG_ON macro calls. For invalid cases, upper layer validation
catches this anyway, so this improves readability and arguably
performance by assigning (mode & S_IFMT) >> 12 directly.
Signed-off-by: Phillip Potter <p...@philpotter.co.uk>
---
fs/ufs/util.h | 39 +++++++++++----------------------------
1 file changed, 11 insertions(+), 28 deletions(-)
diff --git a/fs/ufs/util.h b/fs/ufs/util.h
index 1fd3011ea623..dcf86829edc2 100644
--- a/fs/ufs/util.h
+++ b/fs/ufs/util.h
@@ -16,6 +16,7 @@
* some useful macros
*/
#define in_range(b,first,len) ((b)>=(first)&&(b)<(first)+(len))
+#define S_SHIFT 12
/*
* functions used for retyping
@@ -158,34 +159,16 @@ ufs_set_de_type(struct super_block *sb, struct
ufs_dir_entry *de, int mode)
if ((UFS_SB(sb)->s_flags & UFS_DE_MASK) != UFS_DE_44BSD)
return;
- /*
- * TODO turn this into a table lookup
- */
- switch (mode & S_IFMT) {
- case S_IFSOCK:
- de->d_u.d_44.d_type = DT_SOCK;
- break;
- case S_IFLNK:
- de->d_u.d_44.d_type = DT_LNK;
- break;
- case S_IFREG:
- de->d_u.d_44.d_type = DT_REG;
- break;
- case S_IFBLK:
- de->d_u.d_44.d_type = DT_BLK;
- break;
- case S_IFDIR:
- de->d_u.d_44.d_type = DT_DIR;
- break;
- case S_IFCHR:
- de->d_u.d_44.d_type = DT_CHR;
- break;
- case S_IFIFO:
- de->d_u.d_44.d_type = DT_FIFO;
- break;
- default:
- de->d_u.d_44.d_type = DT_UNKNOWN;
- }
+ /* Compile-time assertions that S_IFx >> S_SHIFT == DT_x */
+ BUILD_BUG_ON(S_IFIFO >> S_SHIFT != DT_FIFO);
+ BUILD_BUG_ON(S_IFCHR >> S_SHIFT != DT_CHR);
+ BUILD_BUG_ON(S_IFDIR >> S_SHIFT != DT_DIR);
+ BUILD_BUG_ON(S_IFBLK >> S_SHIFT != DT_BLK);
+ BUILD_BUG_ON(S_IFREG >> S_SHIFT != DT_REG);
+ BUILD_BUG_ON(S_IFLNK >> S_SHIFT != DT_LNK);
+ BUILD_BUG_ON(S_IFSOCK >> S_SHIFT != DT_SOCK);
+
+ de->d_u.d_44.d_type = (mode & S_IFMT) >> S_SHIFT;
}
static inline u32
--
2.17.2
