[PATCH] x86_64: Use int operations in spinlocks to support more than 128 CPUs spinning.

Pointed out by Eric Dumazet

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-x86_64/spinlock.h b/include/asm-x86_64/spinlock.h
index 6963683..fe484a6 100644 (file)
--- a/include/asm-x86_64/spinlock.h
+++ b/include/asm-x86_64/spinlock.h
@@ -18,22 +18,22 @@
  */
 
 #define __raw_spin_is_locked(x) \
-               (*(volatile signed char *)(&(x)->slock) <= 0)
+               (*(volatile signed int *)(&(x)->slock) <= 0)
 
 #define __raw_spin_lock_string \
        "\n1:\t" \
-       "lock ; decb %0\n\t" \
+       "lock ; decl %0\n\t" \
        "js 2f\n" \
        LOCK_SECTION_START("") \
        "2:\t" \
        "rep;nop\n\t" \
-       "cmpb $0,%0\n\t" \
+       "cmpl $0,%0\n\t" \
        "jle 2b\n\t" \
        "jmp 1b\n" \
        LOCK_SECTION_END
 
 #define __raw_spin_unlock_string \
-       "movb $1,%0" \
+       "movl $1,%0" \
                :"=m" (lock->slock) : : "memory"
 
 static inline void __raw_spin_lock(raw_spinlock_t *lock)
@@ -47,10 +47,10 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
 
 static inline int __raw_spin_trylock(raw_spinlock_t *lock)
 {
-       char oldval;
+       int oldval;
 
        __asm__ __volatile__(
-               "xchgb %b0,%1"
+               "xchgl %0,%1"
                :"=q" (oldval), "=m" (lock->slock)
                :"0" (0) : "memory");