[PATCH 4.9 192/264] uapi: rename ext2_swab() to swab() and share globally in swab.h

Greg Kroah-Hartman
2022-06-23T17:05:19Z

From: Yury Norov <yury.norov@gmail.com>

[ Upstream commit d5767057c9a76a29f073dad66b7fa12a90e8c748 ]

ext2_swab() is defined locally in lib/find_bit.c However it is not
specific to ext2, neither to bitmaps.

There are many potential users of it, so rename it to just swab() and
move to include/uapi/linux/swab.h

ABI guarantees that size of unsigned long corresponds to BITS_PER_LONG,
therefore drop unneeded cast.

Link: http://lkml.kernel.org/r/20200103202846.21616-1-yury.norov@gmail.com
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Joe Perches <joe@perches.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/swab.h | 1 +
include/uapi/linux/swab.h | 10 ++++++++++
lib/find_bit.c | 16 ++--------------
3 files changed, 13 insertions(+), 14 deletions(-)

--- a/include/linux/swab.h
+++ b/include/linux/swab.h
@@ -6,6 +6,7 @@
# define swab16 __swab16
# define swab32 __swab32
# define swab64 __swab64
+# define swab __swab
# define swahw32 __swahw32
# define swahb32 __swahb32
# define swab16p __swab16p
--- a/include/uapi/linux/swab.h
+++ b/include/uapi/linux/swab.h
@@ -3,6 +3,7 @@

#include <linux/types.h>
#include <linux/compiler.h>
+#include <asm/bitsperlong.h>
#include <asm/swab.h>

/*
@@ -131,6 +132,15 @@ static inline __attribute_const__ __u32
__fswab64(x))
#endif

+static __always_inline unsigned long __swab(const unsigned long y)
+{
+#if BITS_PER_LONG == 64
+ return __swab64(y);
+#else /* BITS_PER_LONG == 32 */
+ return __swab32(y);
+#endif
+}
+
/**
* __swahw32 - return a word-swapped 32-bit value
* @x: value to wordswap
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -133,18 +133,6 @@ EXPORT_SYMBOL(find_last_bit);

#ifdef __BIG_ENDIAN

-/* include/linux/byteorder does not support "unsigned long" type */
-static inline unsigned long ext2_swab(const unsigned long y)
-{
-#if BITS_PER_LONG == 64
- return (unsigned long) __swab64((u64) y);
-#elif BITS_PER_LONG == 32
- return (unsigned long) __swab32((u32) y);
-#else
-#error BITS_PER_LONG not defined
-#endif
-}
-
#if !defined(find_next_bit_le) || !defined(find_next_zero_bit_le)
static unsigned long _find_next_bit_le(const unsigned long *addr,
unsigned long nbits, unsigned long start, unsigned long invert)
@@ -157,7 +145,7 @@ static unsigned long _find_next_bit_le(c
tmp = addr[start / BITS_PER_LONG] ^ invert;

/* Handle 1st word. */
- tmp &= ext2_swab(BITMAP_FIRST_WORD_MASK(start));
+ tmp &= swab(BITMAP_FIRST_WORD_MASK(start));
start = round_down(start, BITS_PER_LONG);

while (!tmp) {
@@ -168,7 +156,7 @@ static unsigned long _find_next_bit_le(c
tmp = addr[start / BITS_PER_LONG] ^ invert;
}

- return min(start + __ffs(ext2_swab(tmp)), nbits);
+ return min(start + __ffs(swab(tmp)), nbits);
}
#endif