45 	spinlock_t lock;  member
61 static unsigned int __find_holder(struct block_lock *lock,  in __find_holder()  argument
67 		if (lock->holders[i] == task)  in __find_holder()
75 static void __add_holder(struct block_lock *lock, struct task_struct *task)  in __add_holder()  argument
77 	unsigned int h = __find_holder(lock, NULL);  in __add_holder()
83 	lock->holders[h] = task;  in __add_holder()
86 	t = lock->traces + h;  in __add_holder()
92 static void __del_holder(struct block_lock *lock, struct task_struct *task)  in __del_holder()  argument
94 	unsigned int 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 			stack_trace_print(lock->traces[i].entries,  in __check_holder()
110 					  lock->traces[i].nr_entries, 4);  in __check_holder()
150 static void __wake_many(struct block_lock *lock)  in __wake_many()  argument
154 	BUG_ON(lock->count < 0);  in __wake_many()
155 	list_for_each_entry_safe(w, tmp, &lock->waiters, list) {  in __wake_many()
156 		if (lock->count >= MAX_HOLDERS)  in __wake_many()
160 			if (lock->count > 0)  in __wake_many()
163 			lock->count = -1;  in __wake_many()
164 			__add_holder(lock, w->task);  in __wake_many()
169 		lock->count++;  in __wake_many()
170 		__add_holder(lock, w->task);  in __wake_many()
175 static void bl_init(struct block_lock *lock)  in bl_init()  argument
179 	spin_lock_init(&lock->lock);  in bl_init()
180 	lock->count = 0;  in bl_init()
181 	INIT_LIST_HEAD(&lock->waiters);  in bl_init()
183 		lock->holders[i] = NULL;  in bl_init()
186 static int __available_for_read(struct block_lock *lock)  in __available_for_read()  argument
188 	return lock->count >= 0 &&  in __available_for_read()
189 		lock->count < MAX_HOLDERS &&  in __available_for_read()
190 		list_empty(&lock->waiters);  in __available_for_read()
193 static int bl_down_read(struct block_lock *lock)  in bl_down_read()  argument
198 	spin_lock(&lock->lock);  in bl_down_read()
199 	r = __check_holder(lock);  in bl_down_read()
201 		spin_unlock(&lock->lock);  in bl_down_read()
205 	if (__available_for_read(lock)) {  in bl_down_read()
206 		lock->count++;  in bl_down_read()
207 		__add_holder(lock, current);  in bl_down_read()
208 		spin_unlock(&lock->lock);  in bl_down_read()
216 	list_add_tail(&w.list, &lock->waiters);  in bl_down_read()
217 	spin_unlock(&lock->lock);  in bl_down_read()
224 static int bl_down_read_nonblock(struct block_lock *lock)  in bl_down_read_nonblock()  argument
228 	spin_lock(&lock->lock);  in bl_down_read_nonblock()
229 	r = __check_holder(lock);  in bl_down_read_nonblock()
233 	if (__available_for_read(lock)) {  in bl_down_read_nonblock()
234 		lock->count++;  in bl_down_read_nonblock()
235 		__add_holder(lock, current);  in bl_down_read_nonblock()
241 	spin_unlock(&lock->lock);  in bl_down_read_nonblock()
245 static void bl_up_read(struct block_lock *lock)  in bl_up_read()  argument
247 	spin_lock(&lock->lock);  in bl_up_read()
248 	BUG_ON(lock->count <= 0);  in bl_up_read()
249 	__del_holder(lock, current);  in bl_up_read()
250 	--lock->count;  in bl_up_read()
251 	if (!list_empty(&lock->waiters))  in bl_up_read()
252 		__wake_many(lock);  in bl_up_read()
253 	spin_unlock(&lock->lock);  in bl_up_read()
256 static int bl_down_write(struct block_lock *lock)  in bl_down_write()  argument
261 	spin_lock(&lock->lock);  in bl_down_write()
262 	r = __check_holder(lock);  in bl_down_write()
264 		spin_unlock(&lock->lock);  in bl_down_write()
268 	if (lock->count == 0 && list_empty(&lock->waiters)) {  in bl_down_write()
269 		lock->count = -1;  in bl_down_write()
270 		__add_holder(lock, current);  in bl_down_write()
271 		spin_unlock(&lock->lock);  in bl_down_write()
283 	list_add(&w.list, &lock->waiters);  in bl_down_write()
284 	spin_unlock(&lock->lock);  in bl_down_write()
292 static void bl_up_write(struct block_lock *lock)  in bl_up_write()  argument
294 	spin_lock(&lock->lock);  in bl_up_write()
295 	__del_holder(lock, current);  in bl_up_write()
296 	lock->count = 0;  in bl_up_write()
297 	if (!list_empty(&lock->waiters))  in bl_up_write()
298 		__wake_many(lock);  in bl_up_write()
299 	spin_unlock(&lock->lock);  in bl_up_write()
352 	struct block_lock lock;  member
361 	bl_init(&aux->lock);  in dm_block_manager_alloc_callback()
482 	r = bl_down_read(&aux->lock);  in dm_bm_read_lock()
493 		bl_up_read(&aux->lock);  in dm_bm_read_lock()
518 	r = bl_down_write(&aux->lock);  in dm_bm_write_lock()
529 		bl_up_write(&aux->lock);  in dm_bm_write_lock()
553 	r = bl_down_read_nonblock(&aux->lock);  in dm_bm_read_try_lock()
563 		bl_up_read(&aux->lock);  in dm_bm_read_try_lock()
589 	r = bl_down_write(&aux->lock);  in dm_bm_write_lock_zero()
608 		bl_up_write(&aux->lock);  in dm_bm_unlock()
610 		bl_up_read(&aux->lock);  in dm_bm_unlock()