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authorDavid S. Miller <davem@davemloft.net>2005-09-14 21:47:01 -0700
committerDavid S. Miller <davem@davemloft.net>2005-09-14 21:47:01 -0700
commit4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f (patch)
tree87a00c97e02a77cdfec517398caa3f1d8f6a2f0d /arch/x86_64/lib
parent4a805e863d6b9466baf7084e1d6fdbe6e0628d8e (diff)
downloadlinux-linaro-stable-4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f.tar.gz
[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>
Diffstat (limited to 'arch/x86_64/lib')
-rw-r--r--arch/x86_64/lib/Makefile2
-rw-r--r--arch/x86_64/lib/dec_and_lock.c40
2 files changed, 0 insertions, 42 deletions
diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile
index 6b26a1c1e9ff..bba5db6cebd6 100644
--- a/arch/x86_64/lib/Makefile
+++ b/arch/x86_64/lib/Makefile
@@ -10,5 +10,3 @@ lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \
usercopy.o getuser.o putuser.o \
thunk.o clear_page.o copy_page.o bitstr.o bitops.o
lib-y += memcpy.o memmove.o memset.o copy_user.o
-
-lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
diff --git a/arch/x86_64/lib/dec_and_lock.c b/arch/x86_64/lib/dec_and_lock.c
deleted file mode 100644
index ab43394dc775..000000000000
--- a/arch/x86_64/lib/dec_and_lock.c
+++ /dev/null
@@ -1,40 +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 <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;
-}