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Commit f59ca058 authored by Shan Hai's avatar Shan Hai Committed by Ingo Molnar
Browse files

locking, lib/atomic64: Annotate atomic64_lock::lock as raw 



The spinlock protected atomic64 operations must be irq safe as they
are used in hard interrupt context and cannot be preempted on -rt:

 NIP [c068b218] rt_spin_lock_slowlock+0x78/0x3a8
  LR [c068b1e0] rt_spin_lock_slowlock+0x40/0x3a8
 Call Trace:
  [eb459b90] [c068b1e0] rt_spin_lock_slowlock+0x40/0x3a8 (unreliable)
  [eb459c20] [c068bdb0] rt_spin_lock+0x40/0x98
  [eb459c40] [c03d2a14] atomic64_read+0x48/0x84
  [eb459c60] [c001aaf4] perf_event_interrupt+0xec/0x28c
  [eb459d10] [c0010138] performance_monitor_exception+0x7c/0x150
  [eb459d30] [c0014170] ret_from_except_full+0x0/0x4c

So annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: default avatarShan Hai <haishan.bai@gmail.com>
Reviewed-by: default avatarYong Zhang <yong.zhang0@gmail.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 3b8f4048

lib/atomic64.c

+22 −22
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ 
 * Ensure each lock is in a separate cacheline.

 */

static union {

	spinlock_t lock;

	raw_spinlock_t lock;

	char pad[L1_CACHE_BYTES];

} atomic64_lock[NR_LOCKS] __cacheline_aligned_in_smp;
@@ -48,9 +48,9 @@ long long atomic64_read(const atomic64_t *v) 
	spinlock_t *lock = lock_addr(v);

	long long val;



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	val = v->counter;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

	return val;

}

EXPORT_SYMBOL(atomic64_read);
@@ -60,9 +60,9 @@ void atomic64_set(atomic64_t *v, long long i) 
	unsigned long flags;

	spinlock_t *lock = lock_addr(v);



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	v->counter = i;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

}

EXPORT_SYMBOL(atomic64_set);
@@ -71,9 +71,9 @@ void atomic64_add(long long a, atomic64_t *v) 
	unsigned long flags;

	spinlock_t *lock = lock_addr(v);



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	v->counter += a;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

}

EXPORT_SYMBOL(atomic64_add);
@@ -83,9 +83,9 @@ long long atomic64_add_return(long long a, atomic64_t *v) 
	spinlock_t *lock = lock_addr(v);

	long long val;



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	val = v->counter += a;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

	return val;

}

EXPORT_SYMBOL(atomic64_add_return);
@@ -95,9 +95,9 @@ void atomic64_sub(long long a, atomic64_t *v) 
	unsigned long flags;

	spinlock_t *lock = lock_addr(v);



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	v->counter -= a;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

}

EXPORT_SYMBOL(atomic64_sub);
@@ -107,9 +107,9 @@ long long atomic64_sub_return(long long a, atomic64_t *v) 
	spinlock_t *lock = lock_addr(v);

	long long val;



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	val = v->counter -= a;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

	return val;

}

EXPORT_SYMBOL(atomic64_sub_return);
@@ -120,11 +120,11 @@ long long atomic64_dec_if_positive(atomic64_t *v) 
	spinlock_t *lock = lock_addr(v);

	long long val;



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	val = v->counter - 1;

	if (val >= 0)

		v->counter = val;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

	return val;

}

EXPORT_SYMBOL(atomic64_dec_if_positive);
@@ -135,11 +135,11 @@ long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n) 
	spinlock_t *lock = lock_addr(v);

	long long val;



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	val = v->counter;

	if (val == o)

		v->counter = n;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

	return val;

}

EXPORT_SYMBOL(atomic64_cmpxchg);
@@ -150,10 +150,10 @@ long long atomic64_xchg(atomic64_t *v, long long new) 
	spinlock_t *lock = lock_addr(v);

	long long val;



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	val = v->counter;

	v->counter = new;

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

	return val;

}

EXPORT_SYMBOL(atomic64_xchg);
@@ -164,12 +164,12 @@ int atomic64_add_unless(atomic64_t *v, long long a, long long u) 
	spinlock_t *lock = lock_addr(v);

	int ret = 0;



	spin_lock_irqsave(lock, flags);

	raw_spin_lock_irqsave(lock, flags);

	if (v->counter != u) {

		v->counter += a;

		ret = 1;

	}

	spin_unlock_irqrestore(lock, flags);

	raw_spin_unlock_irqrestore(lock, flags);

	return ret;

}

EXPORT_SYMBOL(atomic64_add_unless);
@@ -179,7 +179,7 @@ static int init_atomic64_lock(void) 
	int i;



	for (i = 0; i < NR_LOCKS; ++i)

		spin_lock_init(&atomic64_lock[i].lock);

		raw_spin_lock_init(&atomic64_lock[i].lock);

	return 0;

}