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Subject[PATCH] fs: ufs: Remove switch statement from ufs_set_de_type function
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. It is expected that for *nix compatibility
reasons, the relation between S_IFx and DT_x will not change. For
cases where the mode is invalid, upper layer validation catches this
anyway, so this improves readability and arguably performance by
assigning (mode & S_IFMT) >> 12 directly without any jump table
or conditional logic.

Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
---
fs/ufs/util.h | 30 ++----------------------------
1 file changed, 2 insertions(+), 28 deletions(-)

diff --git a/fs/ufs/util.h b/fs/ufs/util.h
index 1fd3011ea623..7e0c0878b9f9 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 +159,7 @@ 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;
- }
+ de->d_u.d_44.d_type = (mode & S_IFMT) >> S_SHIFT;
}

static inline u32
--
2.17.2
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