[PATCH] arm: fix the return value of find_first{_zero}_bit

From: LABBE Corentin
Date: Thu Oct 15 2015 - 02:55:31 EST


Building linux with W=1 on arm give me this warning;
In file included from ../include/linux/nodemask.h:92:0,
from ../include/linux/mmzone.h:16,
from ../include/linux/gfp.h:5,
from ../include/linux/kmod.h:22,
from ../include/linux/module.h:13,
from net/netfilter/xt_nat.mod.c:1:
../include/linux/bitmap.h: In function 'bitmap_empty':
../include/linux/bitmap.h:287:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
return find_first_bit(src, nbits) == nbits;

../include/linux/bitmap.h: In function 'bitmap_full':
../include/linux/bitmap.h:295:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
return find_first_zero_bit(src, nbits) == nbits;

The problem is that find_first{_zero}_bit() return type is unsigned long on
majority of arch.

Since find_first{_zero}_bit cannot return negative value, unsigned long is
the best return type.

After some read, it seems that find_next_bit_[lb]e/_find_next_zero_bit_[lb]e
are also incorectly set as return int.

This patch fix the return type of all thoses functions.

Signed-off-by: LABBE Corentin <clabbe.montjoie@xxxxxxxxx>
---
arch/arm/include/asm/bitops.h | 22 +++++++++++-----------
arch/arm/lib/findbit.S | 8 ++++----
2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h
index e943e6c..868414b 100644
--- a/arch/arm/include/asm/bitops.h
+++ b/arch/arm/include/asm/bitops.h
@@ -159,18 +159,18 @@ extern int _test_and_change_bit(int nr, volatile unsigned long * p);
/*
* Little endian assembly bitops. nr = 0 -> byte 0 bit 0.
*/
-extern int _find_first_zero_bit_le(const void * p, unsigned size);
-extern int _find_next_zero_bit_le(const void * p, int size, int offset);
-extern int _find_first_bit_le(const unsigned long *p, unsigned size);
-extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
+extern unsigned long _find_first_zero_bit_le(const void *p, unsigned size);
+extern unsigned long _find_next_zero_bit_le(const void *p, int size, int offset);
+extern unsigned long _find_first_bit_le(const unsigned long *p, unsigned size);
+extern unsigned long _find_next_bit_le(const unsigned long *p, int size, int offset);

/*
* Big endian assembly bitops. nr = 0 -> byte 3 bit 0.
*/
-extern int _find_first_zero_bit_be(const void * p, unsigned size);
-extern int _find_next_zero_bit_be(const void * p, int size, int offset);
-extern int _find_first_bit_be(const unsigned long *p, unsigned size);
-extern int _find_next_bit_be(const unsigned long *p, int size, int offset);
+extern unsigned long _find_first_zero_bit_be(const void *p, unsigned size);
+extern unsigned long _find_next_zero_bit_be(const void *p, int size, int offset);
+extern unsigned long _find_first_bit_be(const unsigned long *p, unsigned size);
+extern unsigned long _find_next_bit_be(const unsigned long *p, int size, int offset);

#ifndef CONFIG_SMP
/*
@@ -317,19 +317,19 @@ static inline unsigned long __ffs(unsigned long x)

#ifdef __ARMEB__

-static inline int find_first_zero_bit_le(const void *p, unsigned size)
+static inline unsigned long find_first_zero_bit_le(const void *p, unsigned size)
{
return _find_first_zero_bit_le(p, size);
}
#define find_first_zero_bit_le find_first_zero_bit_le

-static inline int find_next_zero_bit_le(const void *p, int size, int offset)
+static inline unsigned long find_next_zero_bit_le(const void *p, int size, int offset)
{
return _find_next_zero_bit_le(p, size, offset);
}
#define find_next_zero_bit_le find_next_zero_bit_le

-static inline int find_next_bit_le(const void *p, int size, int offset)
+static inline unsigned long find_next_bit_le(const void *p, int size, int offset)
{
return _find_next_bit_le(p, size, offset);
}
diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S
index 7848780..b4f6aec 100644
--- a/arch/arm/lib/findbit.S
+++ b/arch/arm/lib/findbit.S
@@ -19,7 +19,7 @@

/*
* Purpose : Find a 'zero' bit
- * Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
+ * Prototype: unsigned long find_first_zero_bit(void *addr, unsigned int maxbit);
*/
ENTRY(_find_first_zero_bit_le)
teq r1, #0
@@ -40,7 +40,7 @@ ENDPROC(_find_first_zero_bit_le)

/*
* Purpose : Find next 'zero' bit
- * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
+ * Prototype: unsigned long find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
*/
ENTRY(_find_next_zero_bit_le)
teq r1, #0
@@ -60,7 +60,7 @@ ENDPROC(_find_next_zero_bit_le)

/*
* Purpose : Find a 'one' bit
- * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit);
+ * Prototype: unsigned long find_first_bit(const unsigned long *addr, unsigned int maxbit);
*/
ENTRY(_find_first_bit_le)
teq r1, #0
@@ -81,7 +81,7 @@ ENDPROC(_find_first_bit_le)

/*
* Purpose : Find next 'one' bit
- * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
+ * Prototype: unsigned long find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
*/
ENTRY(_find_next_bit_le)
teq r1, #0
--
2.4.9

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