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make sure that DNAME_INLINE_LEN is a multiple of word size

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... calling the number of words DNAME_INLINE_WORDS.

The next step will be to have a structure to hold inline name arrays
(both in dentry and in name_snapshot) and use that to alias the
existing arrays of unsigned char there.  That will allow both
full-structure copies and convenient word-by-word accesses.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2024-12-09 19:15:58 -05:00
parent 40384c840e
commit 61bc24ac97
2 changed files with 6 additions and 6 deletions
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4
fs/dcache.c
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@@ -2748,9 +2748,7 @@ static void swap_names(struct dentry *dentry, struct dentry *target)
/*
* Both are internal.
*/
unsigned int i;
BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
for (int i = 0; i < DNAME_INLINE_WORDS; i++) {
swap(((long *) &dentry->d_iname)[i],
((long *) &target->d_iname)[i]);
}

8
include/linux/dcache.h
View File

@@ -68,15 +68,17 @@ extern const struct qstr dotdot_name;
* large memory footprint increase).
*/
#ifdef CONFIG_64BIT
# define DNAME_INLINE_LEN 40 /* 192 bytes */
# define DNAME_INLINE_WORDS 5 /* 192 bytes */
#else
# ifdef CONFIG_SMP
# define DNAME_INLINE_LEN 36 /* 128 bytes */
# define DNAME_INLINE_WORDS 9 /* 128 bytes */
# else
# define DNAME_INLINE_LEN 44 /* 128 bytes */
# define DNAME_INLINE_WORDS 11 /* 128 bytes */
# endif
#endif
#define DNAME_INLINE_LEN (DNAME_INLINE_WORDS*sizeof(unsigned long))
#define d_lock d_lockref.lock
struct dentry {