locking, lib/atomic64: Annotate atomic64_lock::lock as raw
Shan Hai [Thu, 1 Sep 2011 03:32:03 +0000 (11:32 +0800)]
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: Shan Hai <haishan.bai@gmail.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

lib/atomic64.c

index e12ae0d..82b3313 100644 (file)
@@ -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;
 }