fs/zfs/rrwlock.c

84 rrn_find(rrwlock_t *rrl)
88 	if (refcount_count(&rrl->rr_linked_rcount) == 0)
92 		if (rn->rn_rrl == rrl)
102 rrn_add(rrwlock_t *rrl, void *tag)
107 	rn->rn_rrl = rrl;
114  * If a node is found for 'rrl', then remove the node from this
118 rrn_find_and_remove(rrwlock_t *rrl, void *tag)
123 	if (refcount_count(&rrl->rr_linked_rcount) == 0)
127 		if (rn->rn_rrl == rrl && rn->rn_tag == tag) {
141 rrw_init(rrwlock_t *rrl, boolean_t track_all)
143 	mutex_init(&rrl->rr_lock, NULL, MUTEX_DEFAULT, NULL);
144 	cv_init(&rrl->rr_cv, NULL, CV_DEFAULT, NULL);
145 	rrl->rr_writer = NULL;
146 	refcount_create(&rrl->rr_anon_rcount);
147 	refcount_create(&rrl->rr_linked_rcount);
148 	rrl->rr_writer_wanted = B_FALSE;
149 	rrl->rr_track_all = track_all;
153 rrw_destroy(rrwlock_t *rrl)
155 	mutex_destroy(&rrl->rr_lock);
156 	cv_destroy(&rrl->rr_cv);
157 	ASSERT(rrl->rr_writer == NULL);
158 	refcount_destroy(&rrl->rr_anon_rcount);
159 	refcount_destroy(&rrl->rr_linked_rcount);
163 rrw_enter_read_impl(rrwlock_t *rrl, boolean_t prio, void *tag)
165 	mutex_enter(&rrl->rr_lock);
167 	if (rrl->rr_writer == NULL && !rrl->rr_writer_wanted &&
168 	    !rrl->rr_track_all) {
169 		rrl->rr_anon_rcount.rc_count++;
170 		mutex_exit(&rrl->rr_lock);
175 	ASSERT(rrl->rr_writer != curthread);
176 	ASSERT(refcount_count(&rrl->rr_anon_rcount) >= 0);
178 	while (rrl->rr_writer != NULL || (rrl->rr_writer_wanted &&
179 	    refcount_is_zero(&rrl->rr_anon_rcount) && !prio &&
180 	    rrn_find(rrl) == NULL))
181 		cv_wait(&rrl->rr_cv, &rrl->rr_lock);
183 	if (rrl->rr_writer_wanted || rrl->rr_track_all) {
185 		rrn_add(rrl, tag);
186 		(void) refcount_add(&rrl->rr_linked_rcount, tag);
188 		(void) refcount_add(&rrl->rr_anon_rcount, tag);
190 	ASSERT(rrl->rr_writer == NULL);
191 	mutex_exit(&rrl->rr_lock);
195 rrw_enter_read(rrwlock_t *rrl, void *tag)
197 	rrw_enter_read_impl(rrl, B_FALSE, tag);
207 rrw_enter_read_prio(rrwlock_t *rrl, void *tag)
209 	rrw_enter_read_impl(rrl, B_TRUE, tag);
214 rrw_enter_write(rrwlock_t *rrl)
216 	mutex_enter(&rrl->rr_lock);
217 	ASSERT(rrl->rr_writer != curthread);
219 	while (refcount_count(&rrl->rr_anon_rcount) > 0 ||
220 	    refcount_count(&rrl->rr_linked_rcount) > 0 ||
221 	    rrl->rr_writer != NULL) {
222 		rrl->rr_writer_wanted = B_TRUE;
223 		cv_wait(&rrl->rr_cv, &rrl->rr_lock);
225 	rrl->rr_writer_wanted = B_FALSE;
226 	rrl->rr_writer = curthread;
227 	mutex_exit(&rrl->rr_lock);
231 rrw_enter(rrwlock_t *rrl, krw_t rw, void *tag)
234 		rrw_enter_read(rrl, tag);
236 		rrw_enter_write(rrl);
240 rrw_exit(rrwlock_t *rrl, void *tag)
242 	mutex_enter(&rrl->rr_lock);
244 	if (!rrl->rr_writer && rrl->rr_linked_rcount.rc_count == 0) {
245 		rrl->rr_anon_rcount.rc_count--;
246 		if (rrl->rr_anon_rcount.rc_count == 0)
247 			cv_broadcast(&rrl->rr_cv);
248 		mutex_exit(&rrl->rr_lock);
253 	ASSERT(!refcount_is_zero(&rrl->rr_anon_rcount) ||
254 	    !refcount_is_zero(&rrl->rr_linked_rcount) ||
255 	    rrl->rr_writer != NULL);
257 	if (rrl->rr_writer == NULL) {
259 		if (rrn_find_and_remove(rrl, tag)) {
260 			count = refcount_remove(&rrl->rr_linked_rcount, tag);
262 			ASSERT(!rrl->rr_track_all);
263 			count = refcount_remove(&rrl->rr_anon_rcount, tag);
266 			cv_broadcast(&rrl->rr_cv);
268 		ASSERT(rrl->rr_writer == curthread);
269 		ASSERT(refcount_is_zero(&rrl->rr_anon_rcount) &&
270 		    refcount_is_zero(&rrl->rr_linked_rcount));
271 		rrl->rr_writer = NULL;
272 		cv_broadcast(&rrl->rr_cv);
274 	mutex_exit(&rrl->rr_lock);
283 rrw_held(rrwlock_t *rrl, krw_t rw)
287 	mutex_enter(&rrl->rr_lock);
289 		held = (rrl->rr_writer == curthread);
291 		held = (!refcount_is_zero(&rrl->rr_anon_rcount) ||
292 		    rrn_find(rrl) != NULL);
294 	mutex_exit(&rrl->rr_lock);
323 rrm_init(rrmlock_t *rrl, boolean_t track_all)
328 		rrw_init(&rrl->locks[i], track_all);
332 rrm_destroy(rrmlock_t *rrl)
337 		rrw_destroy(&rrl->locks[i]);
341 rrm_enter(rrmlock_t *rrl, krw_t rw, void *tag)
344 		rrm_enter_read(rrl, tag);
346 		rrm_enter_write(rrl);
360 rrm_enter_read(rrmlock_t *rrl, void *tag)
362 	rrw_enter_read(&rrl->locks[RRM_TD_LOCK()], tag);
366 rrm_enter_write(rrmlock_t *rrl)
371 		rrw_enter_write(&rrl->locks[i]);
375 rrm_exit(rrmlock_t *rrl, void *tag)
379 	if (rrl->locks[0].rr_writer == curthread) {
381 			rrw_exit(&rrl->locks[i], tag);
383 		rrw_exit(&rrl->locks[RRM_TD_LOCK()], tag);
388 rrm_held(rrmlock_t *rrl, krw_t rw)
391 		return (rrw_held(&rrl->locks[0], rw));
393 		return (rrw_held(&rrl->locks[RRM_TD_LOCK()], rw));