On Thu, Sep 13, 2012 at 06:01:21PM +1000, Stephen Rothwell wrote:
> Hi all,
>
> After merging the final tree, today's linux-next build (sparc64 defconfig)
> failed like this:
>
> mm/internal.h: In function 'swap_cache_hit':
> mm/internal.h:377:3: error: implicit declaration of function
> 'atomic_dec_if_positive' [-Werror=implicit-function-declaration]
>
> Caused by commit "swap: add a simple detector for inappropriate swapin
> readahead" from the akmp tree. atomic_dec_if_positive() appears to only
> exist on avr32, microblaze, mips, powerpc and x86 ...
>
> I have reverted that commit (and the following trivial fix commit) for
> today.
The x86 implementation of atomic_dec_if_positive is quite generic, how about
add this one?
Signed-off-by: Shaohua Li <s...@fusionio.com>
---
arch/microblaze/include/asm/atomic.h | 3 ++-
arch/powerpc/include/asm/atomic.h | 3 ++-
arch/x86/include/asm/atomic.h | 24 ------------------------
include/linux/atomic.h | 25 +++++++++++++++++++++++++
4 files changed, 29 insertions(+), 26 deletions(-)
Index: linux/arch/microblaze/include/asm/atomic.h
===================================================================
--- linux.orig/arch/microblaze/include/asm/atomic.h 2012-09-13
17:56:54.206807900 +0800
+++ linux/arch/microblaze/include/asm/atomic.h 2012-09-13 17:57:18.202506238
+0800
@@ -9,7 +9,7 @@
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1.
*/
-static inline int atomic_dec_if_positive(atomic_t *v)
+static inline int __atomic_dec_if_positive(atomic_t *v)
{
unsigned long flags;
int res;
@@ -22,5 +22,6 @@ static inline int atomic_dec_if_positive
return res;
}
+#define atomic_dec_if_positive __atomic_dec_if_positive
#endif /* _ASM_MICROBLAZE_ATOMIC_H */
Index: linux/arch/powerpc/include/asm/atomic.h
===================================================================
--- linux.orig/arch/powerpc/include/asm/atomic.h 2012-09-13
17:56:54.210807849 +0800
+++ linux/arch/powerpc/include/asm/atomic.h 2012-09-13 17:57:18.202506238
+0800
@@ -247,7 +247,7 @@ static __inline__ int atomic_inc_not_zer
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
-static __inline__ int atomic_dec_if_positive(atomic_t *v)
+static __inline__ int __atomic_dec_if_positive(atomic_t *v)
{
int t;
@@ -268,6 +268,7 @@ static __inline__ int atomic_dec_if_posi
return t;
}
+#define atomic_dec_if_positive __atomic_dec_if_positive
#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec() smp_mb()
Index: linux/arch/x86/include/asm/atomic.h
===================================================================
--- linux.orig/arch/x86/include/asm/atomic.h 2012-09-13 17:56:54.210807849
+0800
+++ linux/arch/x86/include/asm/atomic.h 2012-09-13 17:57:18.202506238 +0800
@@ -240,30 +240,6 @@ static inline int __atomic_add_unless(at
return c;
}
-
-/*
- * atomic_dec_if_positive - decrement by 1 if old value positive
- * @v: pointer of type atomic_t
- *
- * The function returns the old value of *v minus 1, even if
- * the atomic variable, v, was not decremented.
- */
-static inline int atomic_dec_if_positive(atomic_t *v)
-{
- int c, old, dec;
- c = atomic_read(v);
- for (;;) {
- dec = c - 1;
- if (unlikely(dec < 0))
- break;
- old = atomic_cmpxchg((v), c, dec);
- if (likely(old == c))
- break;
- c = old;
- }
- return dec;
-}
-
/**
* atomic_inc_short - increment of a short integer
* @v: pointer to type int
Index: linux/include/linux/atomic.h
===================================================================
--- linux.orig/include/linux/atomic.h 2012-09-13 17:56:54.210807849 +0800
+++ linux/include/linux/atomic.h 2012-09-13 17:57:18.202506238 +0800
@@ -86,6 +86,31 @@ static inline int atomic_dec_unless_posi
}
#endif
+/*
+ * atomic_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+#ifndef atomic_dec_if_positive
+static inline int atomic_dec_if_positive(atomic_t *v)
+{
+ int c, old, dec;
+ c = atomic_read(v);
+ for (;;) {
+ dec = c - 1;
+ if (unlikely(dec < 0))
+ break;
+ old = atomic_cmpxchg((v), c, dec);
+ if (likely(old == c))
+ break;
+ c = old;
+ }
+ return dec;
+}
+#endif
+
#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
static inline void atomic_or(int i, atomic_t *v)
{
--
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