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bb44f116a1
When a spinlock debugging check hits, we print the CPU number as an informational thing - but there is no guarantee that preemption is off at that point - hence we should use raw_smp_processor_id(). Otherwise DEBUG_PREEMPT will print a warning. With this fix the warning goes away and only the spinlock-debugging info is printed. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
260 lines
5.8 KiB
C
260 lines
5.8 KiB
C
/*
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* Copyright 2005, Red Hat, Inc., Ingo Molnar
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* Released under the General Public License (GPL).
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*
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* This file contains the spinlock/rwlock implementations for
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* DEBUG_SPINLOCK.
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*/
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#include <linux/config.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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static void spin_bug(spinlock_t *lock, const char *msg)
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{
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static long print_once = 1;
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struct task_struct *owner = NULL;
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if (xchg(&print_once, 0)) {
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if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
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owner = lock->owner;
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printk("BUG: spinlock %s on CPU#%d, %s/%d\n",
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msg, raw_smp_processor_id(),
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current->comm, current->pid);
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printk(" lock: %p, .magic: %08x, .owner: %s/%d, .owner_cpu: %d\n",
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lock, lock->magic,
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owner ? owner->comm : "<none>",
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owner ? owner->pid : -1,
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lock->owner_cpu);
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dump_stack();
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#ifdef CONFIG_SMP
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/*
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* We cannot continue on SMP:
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*/
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// panic("bad locking");
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#endif
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}
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}
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#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
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static inline void debug_spin_lock_before(spinlock_t *lock)
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{
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SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
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SPIN_BUG_ON(lock->owner == current, lock, "recursion");
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SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
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lock, "cpu recursion");
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}
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static inline void debug_spin_lock_after(spinlock_t *lock)
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{
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lock->owner_cpu = raw_smp_processor_id();
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lock->owner = current;
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}
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static inline void debug_spin_unlock(spinlock_t *lock)
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{
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SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
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SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked");
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SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
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SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
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lock, "wrong CPU");
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lock->owner = SPINLOCK_OWNER_INIT;
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lock->owner_cpu = -1;
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}
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static void __spin_lock_debug(spinlock_t *lock)
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{
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int print_once = 1;
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u64 i;
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for (;;) {
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for (i = 0; i < loops_per_jiffy * HZ; i++) {
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cpu_relax();
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if (__raw_spin_trylock(&lock->raw_lock))
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return;
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}
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/* lockup suspected: */
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if (print_once) {
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print_once = 0;
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printk("BUG: spinlock lockup on CPU#%d, %s/%d, %p\n",
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raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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}
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}
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}
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void _raw_spin_lock(spinlock_t *lock)
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{
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debug_spin_lock_before(lock);
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if (unlikely(!__raw_spin_trylock(&lock->raw_lock)))
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__spin_lock_debug(lock);
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debug_spin_lock_after(lock);
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}
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int _raw_spin_trylock(spinlock_t *lock)
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{
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int ret = __raw_spin_trylock(&lock->raw_lock);
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if (ret)
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debug_spin_lock_after(lock);
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#ifndef CONFIG_SMP
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/*
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* Must not happen on UP:
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*/
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SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
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#endif
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return ret;
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}
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void _raw_spin_unlock(spinlock_t *lock)
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{
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debug_spin_unlock(lock);
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__raw_spin_unlock(&lock->raw_lock);
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}
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static void rwlock_bug(rwlock_t *lock, const char *msg)
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{
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static long print_once = 1;
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if (xchg(&print_once, 0)) {
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printk("BUG: rwlock %s on CPU#%d, %s/%d, %p\n", msg,
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raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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#ifdef CONFIG_SMP
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/*
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* We cannot continue on SMP:
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*/
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panic("bad locking");
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#endif
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}
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}
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#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
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static void __read_lock_debug(rwlock_t *lock)
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{
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int print_once = 1;
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u64 i;
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for (;;) {
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for (i = 0; i < loops_per_jiffy * HZ; i++) {
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cpu_relax();
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if (__raw_read_trylock(&lock->raw_lock))
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return;
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}
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/* lockup suspected: */
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if (print_once) {
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print_once = 0;
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printk("BUG: read-lock lockup on CPU#%d, %s/%d, %p\n",
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raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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}
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}
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}
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void _raw_read_lock(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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if (unlikely(!__raw_read_trylock(&lock->raw_lock)))
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__read_lock_debug(lock);
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}
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int _raw_read_trylock(rwlock_t *lock)
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{
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int ret = __raw_read_trylock(&lock->raw_lock);
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#ifndef CONFIG_SMP
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/*
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* Must not happen on UP:
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*/
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RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
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#endif
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return ret;
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}
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void _raw_read_unlock(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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__raw_read_unlock(&lock->raw_lock);
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}
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static inline void debug_write_lock_before(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
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RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
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lock, "cpu recursion");
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}
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static inline void debug_write_lock_after(rwlock_t *lock)
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{
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lock->owner_cpu = raw_smp_processor_id();
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lock->owner = current;
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}
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static inline void debug_write_unlock(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
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RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
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lock, "wrong CPU");
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lock->owner = SPINLOCK_OWNER_INIT;
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lock->owner_cpu = -1;
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}
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static void __write_lock_debug(rwlock_t *lock)
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{
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int print_once = 1;
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u64 i;
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for (;;) {
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for (i = 0; i < loops_per_jiffy * HZ; i++) {
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cpu_relax();
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if (__raw_write_trylock(&lock->raw_lock))
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return;
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}
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/* lockup suspected: */
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if (print_once) {
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print_once = 0;
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printk("BUG: write-lock lockup on CPU#%d, %s/%d, %p\n",
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raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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}
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}
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}
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void _raw_write_lock(rwlock_t *lock)
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{
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debug_write_lock_before(lock);
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if (unlikely(!__raw_write_trylock(&lock->raw_lock)))
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__write_lock_debug(lock);
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debug_write_lock_after(lock);
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}
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int _raw_write_trylock(rwlock_t *lock)
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{
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int ret = __raw_write_trylock(&lock->raw_lock);
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if (ret)
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debug_write_lock_after(lock);
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#ifndef CONFIG_SMP
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/*
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* Must not happen on UP:
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*/
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RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
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#endif
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return ret;
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}
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void _raw_write_unlock(rwlock_t *lock)
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{
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debug_write_unlock(lock);
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__raw_write_unlock(&lock->raw_lock);
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}
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