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* [PATCH] arm: fix the return value of find_first{_zero}_bit
@ 2015-10-15  6:54 LABBE Corentin
  2015-10-29  8:05 ` LABBE Corentin
  0 siblings, 1 reply; 2+ messages in thread
From: LABBE Corentin @ 2015-10-15  6:54 UTC (permalink / raw)
  To: linux-arm-kernel

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@gmail.com>
---
 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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2015-10-15  6:54 [PATCH] arm: fix the return value of find_first{_zero}_bit LABBE Corentin
2015-10-29  8:05 ` LABBE Corentin

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