[LIB]: Consolidate _atomic_dec_and_lock()

Several implementations were essentialy a common piece of C code using
the cmpxchg() macro.  Put the implementation in one spot that everyone
can share, and convert sparc64 over to using this.

Alpha is the lone arch-specific implementation, which codes up a
special fast path for the common case in order to avoid GP reloading
which a pure C version would require.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 0 insertions, 48 deletions

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index b22f003eaa6d..d2703cda61ea 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -908,11 +908,6 @@ config IRQBALANCE
  	  The default yes will allow the kernel to do irq load balancing.
 	  Saying no will keep the kernel from doing irq load balancing.
 
-config HAVE_DEC_LOCK
-	bool
-	depends on (SMP || PREEMPT) && X86_CMPXCHG
-	default y
-
 # turning this on wastes a bunch of space.
 # Summit needs it only when NUMA is on
 config BOOT_IOREMAP
diff --git a/arch/i386/lib/Makefile b/arch/i386/lib/Makefile
index 7b1932d20f96..914933e9ec3d 100644
--- a/arch/i386/lib/Makefile
+++ b/arch/i386/lib/Makefile
@@ -7,4 +7,3 @@ lib-y = checksum.o delay.o usercopy.o getuser.o putuser.o memcpy.o strstr.o \
 	bitops.o
 
 lib-$(CONFIG_X86_USE_3DNOW) += mmx.o
-lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
diff --git a/arch/i386/lib/dec_and_lock.c b/arch/i386/lib/dec_and_lock.c
deleted file mode 100644
index 8b81b2524fa6..000000000000
--- a/arch/i386/lib/dec_and_lock.c
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * x86 version of "atomic_dec_and_lock()" using
- * the atomic "cmpxchg" instruction.
- *
- * (For CPU's lacking cmpxchg, we use the slow
- * generic version, and this one never even gets
- * compiled).
- */
-
-#include <linux/spinlock.h>
-#include <linux/module.h>
-#include <asm/atomic.h>
-
-int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
-{
-	int counter;
-	int newcount;
-
-repeat:
-	counter = atomic_read(atomic);
-	newcount = counter-1;
-
-	if (!newcount)
-		goto slow_path;
-
-	asm volatile("lock; cmpxchgl %1,%2"
-		:"=a" (newcount)
-		:"r" (newcount), "m" (atomic->counter), "0" (counter));
-
-	/* If the above failed, "eax" will have changed */
-	if (newcount != counter)
-		goto repeat;
-	return 0;
-
-slow_path:
-	spin_lock(lock);
-	if (atomic_dec_and_test(atomic))
-		return 1;
-	spin_unlock(lock);
-	return 0;
-}
-EXPORT_SYMBOL(_atomic_dec_and_lock);