The patch titled
lib/string.c: introduce memchr_inv()
has been added to the -mm tree. Its filename is
lib-stringc-introduce-memchr_inv.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: lib/string.c: introduce memchr_inv()
From: Akinobu Mita <akinobu.mita@xxxxxxxxx>
memchr_inv() is mainly used to check whether the whole buffer is filled
with just a specified byte.
The function name and prototype are stolen from logfs and the
implementation is from SLUB.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Matt Mackall <mpm@xxxxxxxxxxx>
Acked-by: Joern Engel <joern@xxxxxxxxx>
Cc: Marcin Slusarz <marcin.slusarz@xxxxxxxxx>
Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/logfs/logfs.h | 1
fs/logfs/super.c | 22 ---------------
include/linux/string.h | 1
lib/string.c | 54 +++++++++++++++++++++++++++++++++++++++
mm/slub.c | 47 +--------------------------------
5 files changed, 57 insertions(+), 68 deletions(-)
diff -puN fs/logfs/logfs.h~lib-stringc-introduce-memchr_inv fs/logfs/logfs.h
--- a/fs/logfs/logfs.h~lib-stringc-introduce-memchr_inv
+++ a/fs/logfs/logfs.h
@@ -619,7 +619,6 @@ static inline int logfs_buf_recover(stru
struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index);
void emergency_read_end(struct page *page);
void logfs_crash_dump(struct super_block *sb);
-void *memchr_inv(const void *s, int c, size_t n);
int logfs_statfs(struct dentry *dentry, struct kstatfs *stats);
int logfs_check_ds(struct logfs_disk_super *ds);
int logfs_write_sb(struct super_block *sb);
diff -puN fs/logfs/super.c~lib-stringc-introduce-memchr_inv fs/logfs/super.c
--- a/fs/logfs/super.c~lib-stringc-introduce-memchr_inv
+++ a/fs/logfs/super.c
@@ -92,28 +92,6 @@ void logfs_crash_dump(struct super_block
}
/*
- * TODO: move to lib/string.c
- */
-/**
- * memchr_inv - Find a character in an area of memory.
- * @s: The memory area
- * @c: The byte to search for
- * @n: The size of the area.
- *
- * returns the address of the first character other than @c, or %NULL
- * if the whole buffer contains just @c.
- */
-void *memchr_inv(const void *s, int c, size_t n)
-{
- const unsigned char *p = s;
- while (n-- != 0)
- if ((unsigned char)c != *p++)
- return (void *)(p - 1);
-
- return NULL;
-}
-
-/*
* FIXME: There should be a reserve for root, similar to ext2.
*/
int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
diff -puN include/linux/string.h~lib-stringc-introduce-memchr_inv include/linux/string.h
--- a/include/linux/string.h~lib-stringc-introduce-memchr_inv
+++ a/include/linux/string.h
@@ -114,6 +114,7 @@ extern int memcmp(const void *,const voi
#ifndef __HAVE_ARCH_MEMCHR
extern void * memchr(const void *,int,__kernel_size_t);
#endif
+void *memchr_inv(const void *s, int c, size_t n);
extern char *kstrdup(const char *s, gfp_t gfp);
extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
diff -puN lib/string.c~lib-stringc-introduce-memchr_inv lib/string.c
--- a/lib/string.c~lib-stringc-introduce-memchr_inv
+++ a/lib/string.c
@@ -756,3 +756,57 @@ void *memchr(const void *s, int c, size_
}
EXPORT_SYMBOL(memchr);
#endif
+
+static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
+{
+ while (bytes) {
+ if (*start != value)
+ return (void *)start;
+ start++;
+ bytes--;
+ }
+ return NULL;
+}
+
+/**
+ * memchr_inv - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the first character other than @c, or %NULL
+ * if the whole buffer contains just @c.
+ */
+void *memchr_inv(const void *start, int c, size_t bytes)
+{
+ u8 value = c;
+ u64 value64;
+ unsigned int words, prefix;
+
+ if (bytes <= 16)
+ return check_bytes8(start, value, bytes);
+
+ value64 = value | value << 8 | value << 16 | value << 24;
+ value64 = (value64 & 0xffffffff) | value64 << 32;
+ prefix = 8 - ((unsigned long)start) % 8;
+
+ if (prefix) {
+ u8 *r = check_bytes8(start, value, prefix);
+ if (r)
+ return r;
+ start += prefix;
+ bytes -= prefix;
+ }
+
+ words = bytes / 8;
+
+ while (words) {
+ if (*(u64 *)start != value64)
+ return check_bytes8(start, value, 8);
+ start += 8;
+ words--;
+ }
+
+ return check_bytes8(start, value, bytes % 8);
+}
+EXPORT_SYMBOL(memchr_inv);
diff -puN mm/slub.c~lib-stringc-introduce-memchr_inv mm/slub.c
--- a/mm/slub.c~lib-stringc-introduce-memchr_inv
+++ a/mm/slub.c
@@ -681,49 +681,6 @@ static void init_object(struct kmem_cach
memset(p + s->objsize, val, s->inuse - s->objsize);
}
-static u8 *check_bytes8(u8 *start, u8 value, unsigned int bytes)
-{
- while (bytes) {
- if (*start != value)
- return start;
- start++;
- bytes--;
- }
- return NULL;
-}
-
-static u8 *check_bytes(u8 *start, u8 value, unsigned int bytes)
-{
- u64 value64;
- unsigned int words, prefix;
-
- if (bytes <= 16)
- return check_bytes8(start, value, bytes);
-
- value64 = value | value << 8 | value << 16 | value << 24;
- value64 = (value64 & 0xffffffff) | value64 << 32;
- prefix = 8 - ((unsigned long)start) % 8;
-
- if (prefix) {
- u8 *r = check_bytes8(start, value, prefix);
- if (r)
- return r;
- start += prefix;
- bytes -= prefix;
- }
-
- words = bytes / 8;
-
- while (words) {
- if (*(u64 *)start != value64)
- return check_bytes8(start, value, 8);
- start += 8;
- words--;
- }
-
- return check_bytes8(start, value, bytes % 8);
-}
-
static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
void *from, void *to)
{
@@ -738,7 +695,7 @@ static int check_bytes_and_report(struct
u8 *fault;
u8 *end;
- fault = check_bytes(start, value, bytes);
+ fault = memchr_inv(start, value, bytes);
if (!fault)
return 1;
@@ -831,7 +788,7 @@ static int slab_pad_check(struct kmem_ca
if (!remainder)
return 1;
- fault = check_bytes(end - remainder, POISON_INUSE, remainder);
+ fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
if (!fault)
return 1;
while (end > fault && end[-1] == POISON_INUSE)
_
Patches currently in -mm which might be from akinobu.mita@xxxxxxxxx are
linux-next.patch
ext4-use-proper-little-endian-bitops.patch
ocfs2-avoid-unaligned-access-to-dqc_bitmap.patch
mm-debug-pageallocc-use-plain-__ratelimit-instead-of-printk_ratelimit.patch
lib-stringc-introduce-memchr_inv.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
