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author | David S. Miller <davem@davemloft.net> | 2005-09-14 21:47:01 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2005-09-14 21:47:01 -0700 |
commit | 4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f (patch) | |
tree | 87a00c97e02a77cdfec517398caa3f1d8f6a2f0d /arch/i386 | |
parent | 4a805e863d6b9466baf7084e1d6fdbe6e0628d8e (diff) | |
download | linux-4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f.tar.bz2 |
[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/i386')
-rw-r--r-- | arch/i386/Kconfig | 5 | ||||
-rw-r--r-- | arch/i386/lib/Makefile | 1 | ||||
-rw-r--r-- | arch/i386/lib/dec_and_lock.c | 42 |
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); |