- unsigned long stuck = INIT_STUCK;
- int cpu = smp_processor_id();
-
-again:
- if ( test_and_set_bit(31,&(rw)->lock) ) /* someone has a write lock */
- {
- while ( (rw)->lock & (1<<31) ) /* wait for write lock */
- {
- if(!--stuck)
- {
- printk("write_lock(%p) CPU#%d lock %lx)\n",
- rw, cpu,rw->lock);
- stuck = INIT_STUCK;
- }
- barrier();
- }
- goto again;
- }
-
- if ( (rw)->lock & ~(1<<31)) /* someone has a read lock */
- {
- /* clear our write lock and wait for reads to go away */
- clear_bit(31,&(rw)->lock);
- while ( (rw)->lock & ~(1<<31) )
- {
- if(!--stuck)
- {
- printk("write_lock(%p) 2 CPU#%d lock %lx)\n",
- rw, cpu,rw->lock);
+ unsigned int stuck;
+
+ while (cmpxchg(&rw->lock, 0, -1) != 0) {
+ stuck = INIT_STUCK;
+ while (!write_can_lock(rw)) {
+ if (--stuck == 0) {
+ printk("write_lock(%p) CPU#%d lock %d)\n",
+ rw, _smp_processor_id(), rw->lock);