[PATCH] fs: ufs: Convert ufs_set_de_type to use lookup table

From: Phillip Potter
Date: Mon Oct 01 2018 - 11:33:16 EST


Modify ufs_set_de_type function in fs/ufs/util.h to use a lookup
table rather than a switch statement, as per the TODO comment.

Signed-off-by: Phillip Potter <phil@xxxxxxxxxxxxxxxx>
---
diff --git a/fs/ufs/util.h b/fs/ufs/util.h
index 1907be6d5808..1edf4c6454e3 100644
--- a/fs/ufs/util.h
+++ b/fs/ufs/util.h
@@ -155,37 +155,31 @@ ufs_set_de_namlen(struct super_block *sb, struct ufs_dir_entry *de, u16 value)
static inline void
ufs_set_de_type(struct super_block *sb, struct ufs_dir_entry *de, int mode)
{
+ /* type lookup table, DT_UNKNOWN is default type if no case holds */
+ const int mode_table[] = {
+ DT_UNKNOWN,
+ DT_FIFO, /* mode & S_IFMT == S_IFIFO case */
+ DT_CHR, /* mode & S_IFMT == S_IFCHR case */
+ DT_UNKNOWN,
+ DT_DIR, /* mode & S_IFMT == S_IFDIR case */
+ DT_UNKNOWN,
+ DT_BLK, /* mode & S_IFMT == S_IFBLK case */
+ DT_UNKNOWN,
+ DT_REG, /* mode & S_IFMT == S_IFREG case */
+ DT_UNKNOWN,
+ DT_LNK, /* mode & S_IFMT == S_IFLNK case */
+ DT_UNKNOWN,
+ DT_SOCK, /* mode & S_IFMT == S_IFSOCK case */
+ DT_UNKNOWN,
+ DT_UNKNOWN,
+ DT_UNKNOWN
+ };
+
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;
- }
+ /* shift (mode & S_IFMT) right 12 bits to index into table */
+ de->d_u.d_44.d_type = mode_table[(mode & S_IFMT) >> 12];
}

static inline u32