diff options
Diffstat (limited to 'spinlock.c')
| -rw-r--r-- | spinlock.c | 8 |
1 files changed, 6 insertions, 2 deletions
@@ -30,8 +30,10 @@ acquire(struct spinlock * lock) if(holding(lock)) panic("acquire"); - if(cpus[cpu()].nlock++ == 0) - cli(); + if(cpus[cpu()].nlock == 0) + cli(); + cpus[cpu()].nlock++; + while(cmpxchg(0, 1, &lock->locked) == 1) ; cpuid(0, 0, 0, 0, 0); // memory barrier @@ -53,6 +55,8 @@ release(struct spinlock * lock) lock->locked = 0; if(--cpus[cpu()].nlock == 0) sti(); + // xxx we may have just turned interrupts on during + // an interrupt, is that ok? } int |