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/*
* Copyright 2005, Red Hat, Inc., Ingo Molnar
* Released under the General Public License (GPL).
*
* This file contains the spinlock/rwlock implementations for
* DEBUG_SPINLOCK.
*/
#include <linux/config.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
static void spin_bug(spinlock_t *lock, const char *msg)
{
static long print_once = 1;
struct task_struct *owner = NULL;
if (xchg(&print_once, 0)) {
if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
owner = lock->owner;
printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
msg, raw_smp_processor_id(),
current->comm, current->pid);
printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
".owner_cpu: %d\n",
lock, lock->magic,
owner ? owner->comm : "<none>",
owner ? owner->pid : -1,
lock->owner_cpu);
dump_stack();
#ifdef CONFIG_SMP
/*
* We cannot continue on SMP:
*/
// panic("bad locking");
#endif
}
}
#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
static inline void debug_spin_lock_before(spinlock_t *lock)
{
SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
SPIN_BUG_ON(lock->owner == current, lock, "recursion");
SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
lock, "cpu recursion");
}
static inline void debug_spin_lock_after(spinlock_t *lock)
{
lock->owner_cpu = raw_smp_processor_id();
lock->owner = current;
}
static inline void debug_spin_unlock(spinlock_t *lock)
{
SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked");
SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
lock, "wrong CPU");
lock->owner = SPINLOCK_OWNER_INIT;
lock->owner_cpu = -1;
}
static void __spin_lock_debug(spinlock_t *lock)
{
int print_once = 1;
u64 i;
for (;;) {
for (i = 0; i < loops_per_jiffy * HZ; i++) {
if (__raw_spin_trylock(&lock->raw_lock))
return;
__delay(1);
}
/* lockup suspected: */
if (print_once) {
print_once = 0;
printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "
"%s/%d, %p\n",
raw_smp_processor_id(), current->comm,
current->pid, lock);
dump_stack();
}
}
}
void _raw_spin_lock(spinlock_t *lock)
{
debug_spin_lock_before(lock);
if (unlikely(!__raw_spin_trylock(&lock->raw_lock)))
__spin_lock_debug(lock);
debug_spin_lock_after(lock);
}
int _raw_spin_trylock(spinlock_t *lock)
{
int ret = __raw_spin_trylock(&lock->raw_lock);
if (ret)
debug_spin_lock_after(lock);
#ifndef CONFIG_SMP
/*
* Must not happen on UP:
*/
SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
#endif
return ret;
}
void _raw_spin_unlock(spinlock_t *lock)
{
debug_spin_unlock(lock);
__raw_spin_unlock(&lock->raw_lock);
}
static void rwlock_bug(rwlock_t *lock, const char *msg)
{
static long print_once = 1;
if (xchg(&print_once, 0)) {
printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
msg, raw_smp_processor_id(), current->comm,
current->pid, lock);
dump_stack();
#ifdef CONFIG_SMP
/*
* We cannot continue on SMP:
*/
panic("bad locking");
#endif
}
}
#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
#if 0 /* __write_lock_debug() can lock up - maybe this can too? */
static void __read_lock_debug(rwlock_t *lock)
{
int print_once = 1;
u64 i;
for (;;) {
for (i = 0; i < loops_per_jiffy * HZ; i++) {
if (__raw_read_trylock(&lock->raw_lock))
return;
__delay(1);
}
/* lockup suspected: */
if (print_once) {
print_once = 0;
printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
"%s/%d, %p\n",
raw_smp_processor_id(), current->comm,
current->pid, lock);
dump_stack();
}
}
}
#endif
void _raw_read_lock(rwlock_t *lock)
{
RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
__raw_read_lock(&lock->raw_lock);
}
int _raw_read_trylock(rwlock_t *lock)
{
int ret = __raw_read_trylock(&lock->raw_lock);
#ifndef CONFIG_SMP
/*
* Must not happen on UP:
*/
RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
#endif
return ret;
}
void _raw_read_unlock(rwlock_t *lock)
{
RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
__raw_read_unlock(&lock->raw_lock);
}
static inline void debug_write_lock_before(rwlock_t *lock)
{
RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
lock, "cpu recursion");
}
static inline void debug_write_lock_after(rwlock_t *lock)
{
lock->owner_cpu = raw_smp_processor_id();
lock->owner = current;
}
static inline void debug_write_unlock(rwlock_t *lock)
{
RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
lock, "wrong CPU");
lock->owner = SPINLOCK_OWNER_INIT;
lock->owner_cpu = -1;
}
#if 0 /* This can cause lockups */
static void __write_lock_debug(rwlock_t *lock)
{
int print_once = 1;
u64 i;
for (;;) {
for (i = 0; i < loops_per_jiffy * HZ; i++) {
if (__raw_write_trylock(&lock->raw_lock))
return;
__delay(1);
}
/* lockup suspected: */
if (print_once) {
print_once = 0;
printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
"%s/%d, %p\n",
raw_smp_processor_id(), current->comm,
current->pid, lock);
dump_stack();
}
}
}
#endif
void _raw_write_lock(rwlock_t *lock)
{
debug_write_lock_before(lock);
__raw_write_lock(&lock->raw_lock);
debug_write_lock_after(lock);
}
int _raw_write_trylock(rwlock_t *lock)
{
int ret = __raw_write_trylock(&lock->raw_lock);
if (ret)
debug_write_lock_after(lock);
#ifndef CONFIG_SMP
/*
* Must not happen on UP:
*/
RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
#endif
return ret;
}
void _raw_write_unlock(rwlock_t *lock)
{
debug_write_unlock(lock);
__raw_write_unlock(&lock->raw_lock);
}
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