Revision 40509ca982c00c4b70fc00be887509feca0bff15 authored by Johan Hovold on 19 March 2013, 08:21:22 UTC, committed by Greg Kroah-Hartman on 21 March 2013, 22:59:05 UTC
Use the port wait queue and make sure to check the serial disconnected flag before accessing private port data after waking up. This is is needed as the private port data (including the wait queue itself) can be gone when waking up after a disconnect. Cc: stable <stable@vger.kernel.org> Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 parent 8edfdab
atomic64.c
/*
* Generic implementation of 64-bit atomics using spinlocks,
* useful on processors that don't have 64-bit atomic instructions.
*
* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/types.h>
#include <linux/cache.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/atomic.h>
/*
* We use a hashed array of spinlocks to provide exclusive access
* to each atomic64_t variable. Since this is expected to used on
* systems with small numbers of CPUs (<= 4 or so), we use a
* relatively small array of 16 spinlocks to avoid wasting too much
* memory on the spinlock array.
*/
#define NR_LOCKS 16
/*
* Ensure each lock is in a separate cacheline.
*/
static union {
raw_spinlock_t lock;
char pad[L1_CACHE_BYTES];
} atomic64_lock[NR_LOCKS] __cacheline_aligned_in_smp = {
[0 ... (NR_LOCKS - 1)] = {
.lock = __RAW_SPIN_LOCK_UNLOCKED(atomic64_lock.lock),
},
};
static inline raw_spinlock_t *lock_addr(const atomic64_t *v)
{
unsigned long addr = (unsigned long) v;
addr >>= L1_CACHE_SHIFT;
addr ^= (addr >> 8) ^ (addr >> 16);
return &atomic64_lock[addr & (NR_LOCKS - 1)].lock;
}
long long atomic64_read(const atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
long long val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
raw_spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_read);
void atomic64_set(atomic64_t *v, long long i)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
raw_spin_lock_irqsave(lock, flags);
v->counter = i;
raw_spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(atomic64_set);
void atomic64_add(long long a, atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
raw_spin_lock_irqsave(lock, flags);
v->counter += a;
raw_spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(atomic64_add);
long long atomic64_add_return(long long a, atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
long long val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter += a;
raw_spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_add_return);
void atomic64_sub(long long a, atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
raw_spin_lock_irqsave(lock, flags);
v->counter -= a;
raw_spin_unlock_irqrestore(lock, flags);
}
EXPORT_SYMBOL(atomic64_sub);
long long atomic64_sub_return(long long a, atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
long long val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter -= a;
raw_spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_sub_return);
long long atomic64_dec_if_positive(atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
long long val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter - 1;
if (val >= 0)
v->counter = val;
raw_spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_dec_if_positive);
long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
long long val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
if (val == o)
v->counter = n;
raw_spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_cmpxchg);
long long atomic64_xchg(atomic64_t *v, long long new)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
long long val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
v->counter = new;
raw_spin_unlock_irqrestore(lock, flags);
return val;
}
EXPORT_SYMBOL(atomic64_xchg);
int atomic64_add_unless(atomic64_t *v, long long a, long long u)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
int ret = 0;
raw_spin_lock_irqsave(lock, flags);
if (v->counter != u) {
v->counter += a;
ret = 1;
}
raw_spin_unlock_irqrestore(lock, flags);
return ret;
}
EXPORT_SYMBOL(atomic64_add_unless);
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