diff options
author | David S. Miller <davem@davemloft.net> | 2005-09-15 04:47:01 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2005-09-15 04:47:01 (GMT) |
commit | 4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f (patch) | |
tree | 87a00c97e02a77cdfec517398caa3f1d8f6a2f0d /arch/x86_64/lib | |
parent | 4a805e863d6b9466baf7084e1d6fdbe6e0628d8e (diff) | |
download | linux-fsl-qoriq-4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f.tar.xz |
[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/Makefile | 2 | ||||
-rw-r--r-- | arch/x86_64/lib/dec_and_lock.c | 40 |
2 files changed, 0 insertions, 42 deletions
diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile index 6b26a1c..bba5db6 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 ab43394..0000000 --- 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; -} |