/* * 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("BUG: spinlock %s on CPU#%d, %s/%d\n",			msg, raw_smp_processor_id(),			current->comm, current->pid);		printk(" 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++) {			cpu_relax();			if (__raw_spin_trylock(&lock->raw_lock))				return;		}		/* lockup suspected: */		if (print_once) {			print_once = 0;			printk("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("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) static void __read_lock_debug(rwlock_t *lock){	int print_once = 1;	u64 i; 	for (;;) {		for (i = 0; i < loops_per_jiffy * HZ; i++) {			cpu_relax();			if (__raw_read_trylock(&lock->raw_lock))				return;		}		/* lockup suspected: */		if (print_once) {			print_once = 0;			printk("BUG: read-lock lockup on CPU#%d, %s/%d, %p\n",				raw_smp_processor_id(), current->comm,				current->pid, lock);			dump_stack();		}	}} void _raw_read_lock(rwlock_t *lock){	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");	if (unlikely(!__raw_read_trylock(&lock->raw_lock)))		__read_lock_debug(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;} static void __write_lock_debug(rwlock_t *lock){	int print_once = 1;	u64 i; 	for (;;) {		for (i = 0; i < loops_per_jiffy * HZ; i++) {			cpu_relax();			if (__raw_write_trylock(&lock->raw_lock))				return;		}		/* lockup suspected: */		if (print_once) {			print_once = 0;			printk("BUG: write-lock lockup on CPU#%d, %s/%d, %p\n",				raw_smp_processor_id(), current->comm,				current->pid, lock);			dump_stack();		}	}} void _raw_write_lock(rwlock_t *lock){	debug_write_lock_before(lock);	if (unlikely(!__raw_write_trylock(&lock->raw_lock)))		__write_lock_debug(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);}