tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * arch/alpha/lib/dec_and_lock.c
3 *
4 * ll/sc version of atomic_dec_and_lock()
5 *
6 */
7
8#include <linux/spinlock.h>
9#include <linux/atomic.h>
10#include <linux/export.h>
11
12 asm (".text \n\
13 .global _atomic_dec_and_lock \n\
14 .ent _atomic_dec_and_lock \n\
15 .align 4 \n\
16_atomic_dec_and_lock: \n\
17 .prologue 0 \n\
181: ldl_l $1, 0($16) \n\
19 subl $1, 1, $1 \n\
20 beq $1, 2f \n\
21 stl_c $1, 0($16) \n\
22 beq $1, 4f \n\
23 mb \n\
24 clr $0 \n\
25 ret \n\
262: br $29, 3f \n\
273: ldgp $29, 0($29) \n\
28 br $atomic_dec_and_lock_1..ng \n\
29 .subsection 2 \n\
304: br 1b \n\
31 .previous \n\
32 .end _atomic_dec_and_lock");
33
34static int __used atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock)
35{
36 /* Slow path */
37 spin_lock(lock);
38 if (atomic_dec_and_test(atomic))
39 return 1;
40 spin_unlock(lock);
41 return 0;
42}
43EXPORT_SYMBOL(_atomic_dec_and_lock);