41 	spinlock_t lock;  member
58 static unsigned __find_holder(struct block_lock *lock,  in __find_holder()  argument
64 		if (lock->holders[i] == task)  in __find_holder()
72 static void __add_holder(struct block_lock *lock, struct task_struct *task)  in __add_holder()  argument
74 	unsigned h = __find_holder(lock, NULL);  in __add_holder()
80 	lock->holders[h] = task;  in __add_holder()
83 	t = lock->traces + h;  in __add_holder()
86 	t->entries = lock->entries[h];  in __add_holder()
93 static void __del_holder(struct block_lock *lock, struct task_struct *task)  in __del_holder()  argument
95 	unsigned h = __find_holder(lock, task);  in __del_holder()
96 	lock->holders[h] = NULL;  in __del_holder()
100 static int __check_holder(struct block_lock *lock)  in __check_holder()  argument
105 		if (lock->holders[i] == current) {  in __check_holder()
109 			print_stack_trace(lock->traces + i, 4);  in __check_holder()
149 static void __wake_many(struct block_lock *lock)  in __wake_many()  argument
153 	BUG_ON(lock->count < 0);  in __wake_many()
154 	list_for_each_entry_safe(w, tmp, &lock->waiters, list) {  in __wake_many()
155 		if (lock->count >= MAX_HOLDERS)  in __wake_many()
159 			if (lock->count > 0)  in __wake_many()
162 			lock->count = -1;  in __wake_many()
163 			__add_holder(lock, w->task);  in __wake_many()
168 		lock->count++;  in __wake_many()
169 		__add_holder(lock, w->task);  in __wake_many()
174 static void bl_init(struct block_lock *lock)  in bl_init()  argument
178 	spin_lock_init(&lock->lock);  in bl_init()
179 	lock->count = 0;  in bl_init()
180 	INIT_LIST_HEAD(&lock->waiters);  in bl_init()
182 		lock->holders[i] = NULL;  in bl_init()
185 static int __available_for_read(struct block_lock *lock)  in __available_for_read()  argument
187 	return lock->count >= 0 &&  in __available_for_read()
188 		lock->count < MAX_HOLDERS &&  in __available_for_read()
189 		list_empty(&lock->waiters);  in __available_for_read()
192 static int bl_down_read(struct block_lock *lock)  in bl_down_read()  argument
197 	spin_lock(&lock->lock);  in bl_down_read()
198 	r = __check_holder(lock);  in bl_down_read()
200 		spin_unlock(&lock->lock);  in bl_down_read()
204 	if (__available_for_read(lock)) {  in bl_down_read()
205 		lock->count++;  in bl_down_read()
206 		__add_holder(lock, current);  in bl_down_read()
207 		spin_unlock(&lock->lock);  in bl_down_read()
215 	list_add_tail(&w.list, &lock->waiters);  in bl_down_read()
216 	spin_unlock(&lock->lock);  in bl_down_read()
223 static int bl_down_read_nonblock(struct block_lock *lock)  in bl_down_read_nonblock()  argument
227 	spin_lock(&lock->lock);  in bl_down_read_nonblock()
228 	r = __check_holder(lock);  in bl_down_read_nonblock()
232 	if (__available_for_read(lock)) {  in bl_down_read_nonblock()
233 		lock->count++;  in bl_down_read_nonblock()
234 		__add_holder(lock, current);  in bl_down_read_nonblock()
240 	spin_unlock(&lock->lock);  in bl_down_read_nonblock()
244 static void bl_up_read(struct block_lock *lock)  in bl_up_read()  argument
246 	spin_lock(&lock->lock);  in bl_up_read()
247 	BUG_ON(lock->count <= 0);  in bl_up_read()
248 	__del_holder(lock, current);  in bl_up_read()
249 	--lock->count;  in bl_up_read()
250 	if (!list_empty(&lock->waiters))  in bl_up_read()
251 		__wake_many(lock);  in bl_up_read()
252 	spin_unlock(&lock->lock);  in bl_up_read()
255 static int bl_down_write(struct block_lock *lock)  in bl_down_write()  argument
260 	spin_lock(&lock->lock);  in bl_down_write()
261 	r = __check_holder(lock);  in bl_down_write()
263 		spin_unlock(&lock->lock);  in bl_down_write()
267 	if (lock->count == 0 && list_empty(&lock->waiters)) {  in bl_down_write()
268 		lock->count = -1;  in bl_down_write()
269 		__add_holder(lock, current);  in bl_down_write()
270 		spin_unlock(&lock->lock);  in bl_down_write()
282 	list_add(&w.list, &lock->waiters);  in bl_down_write()
283 	spin_unlock(&lock->lock);  in bl_down_write()
291 static void bl_up_write(struct block_lock *lock)  in bl_up_write()  argument
293 	spin_lock(&lock->lock);  in bl_up_write()
294 	__del_holder(lock, current);  in bl_up_write()
295 	lock->count = 0;  in bl_up_write()
296 	if (!list_empty(&lock->waiters))  in bl_up_write()
297 		__wake_many(lock);  in bl_up_write()
298 	spin_unlock(&lock->lock);  in bl_up_write()
351 	struct block_lock lock;  member
359 	bl_init(&aux->lock);  in dm_block_manager_alloc_callback()
469 	r = bl_down_read(&aux->lock);  in dm_bm_read_lock()
480 		bl_up_read(&aux->lock);  in dm_bm_read_lock()
505 	r = bl_down_write(&aux->lock);  in dm_bm_write_lock()
516 		bl_up_write(&aux->lock);  in dm_bm_write_lock()
540 	r = bl_down_read_nonblock(&aux->lock);  in dm_bm_read_try_lock()
550 		bl_up_read(&aux->lock);  in dm_bm_read_try_lock()
576 	r = bl_down_write(&aux->lock);  in dm_bm_write_lock_zero()
596 		bl_up_write(&aux->lock);  in dm_bm_unlock()
598 		bl_up_read(&aux->lock);  in dm_bm_unlock()