1 // SPDX-License-Identifier: MIT
3  * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
8  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
25  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
33  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
36 #include <linux/dma-resv.h>
37 #include <linux/dma-fence-array.h>
47  * The reservation object provides a mechanism to manage a container of
52  * locked write-side updates.
76 	tmp = (long)rcu_dereference_check(list->table[index],  in dma_resv_list_entry()
91 	RCU_INIT_POINTER(list->table[index], (struct dma_fence *)tmp);  in dma_resv_list_set()
111 	list->max_fences = (size - offsetof(typeof(*list), table)) /  in dma_resv_list_alloc()
112 		sizeof(*list->table);  in dma_resv_list_alloc()
125 	for (i = 0; i < list->num_fences; ++i) {  in dma_resv_list_free()
135  * dma_resv_init - initialize a reservation object
140 	ww_mutex_init(&obj->lock, &reservation_ww_class);  in dma_resv_init()
142 	RCU_INIT_POINTER(obj->fences, NULL);  in dma_resv_init()
147  * dma_resv_fini - destroys a reservation object
156 	dma_resv_list_free(rcu_dereference_protected(obj->fences, true));  in dma_resv_fini()
157 	ww_mutex_destroy(&obj->lock);  in dma_resv_fini()
161 /* Dereference the fences while ensuring RCU rules */
164 	return rcu_dereference_check(obj->fences, dma_resv_held(obj));  in dma_resv_fences_list()
168  * dma_resv_reserve_fences - Reserve space to add fences to a dma_resv object.
175  * Note that the preallocated slots need to be re-reserved if @obj is unlocked
180  * Zero for success, or -errno
190 	if (old && old->max_fences) {  in dma_resv_reserve_fences()
191 		if ((old->num_fences + num_fences) <= old->max_fences)  in dma_resv_reserve_fences()
193 		max = max(old->num_fences + num_fences, old->max_fences * 2);  in dma_resv_reserve_fences()
200 		return -ENOMEM;  in dma_resv_reserve_fences()
208 	for (i = 0, j = 0, k = max; i < (old ? old->num_fences : 0); ++i) {  in dma_resv_reserve_fences()
214 			RCU_INIT_POINTER(new->table[--k], fence);  in dma_resv_reserve_fences()
218 	new->num_fences = j;  in dma_resv_reserve_fences()
228 	rcu_assign_pointer(obj->fences, new);  in dma_resv_reserve_fences()
237 		fence = rcu_dereference_protected(new->table[i],  in dma_resv_reserve_fences()
249  * dma_resv_reset_max_fences - reset fences for debugging
252  * Reset the number of pre-reserved fence slots to test that drivers do
264 		fences->max_fences = fences->num_fences;  in dma_resv_reset_max_fences()
270  * dma_resv_add_fence - Add a fence to the dma_resv obj
297 	count = fobj->num_fences;  in dma_resv_add_fence()
303 		if ((old->context == fence->context && old_usage >= usage &&  in dma_resv_add_fence()
312 	BUG_ON(fobj->num_fences >= fobj->max_fences);  in dma_resv_add_fence()
317 	smp_store_mb(fobj->num_fences, count);  in dma_resv_add_fence()
322  * dma_resv_replace_fences - replace fences in the dma_resv obj
345 	for (i = 0; list && i < list->num_fences; ++i) {  in dma_resv_replace_fences()
349 		if (old->context != context)  in dma_resv_replace_fences()
361 	cursor->index = 0;  in dma_resv_iter_restart_unlocked()
362 	cursor->num_fences = 0;  in dma_resv_iter_restart_unlocked()
363 	cursor->fences = dma_resv_fences_list(cursor->obj);  in dma_resv_iter_restart_unlocked()
364 	if (cursor->fences)  in dma_resv_iter_restart_unlocked()
365 		cursor->num_fences = cursor->fences->num_fences;  in dma_resv_iter_restart_unlocked()
366 	cursor->is_restarted = true;  in dma_resv_iter_restart_unlocked()
372 	if (!cursor->fences)  in dma_resv_iter_walk_unlocked()
377 		dma_fence_put(cursor->fence);  in dma_resv_iter_walk_unlocked()
379 		if (cursor->index >= cursor->num_fences) {  in dma_resv_iter_walk_unlocked()
380 			cursor->fence = NULL;  in dma_resv_iter_walk_unlocked()
385 		dma_resv_list_entry(cursor->fences, cursor->index++,  in dma_resv_iter_walk_unlocked()
386 				    cursor->obj, &cursor->fence,  in dma_resv_iter_walk_unlocked()
387 				    &cursor->fence_usage);  in dma_resv_iter_walk_unlocked()
388 		cursor->fence = dma_fence_get_rcu(cursor->fence);  in dma_resv_iter_walk_unlocked()
389 		if (!cursor->fence) {  in dma_resv_iter_walk_unlocked()
394 		if (!dma_fence_is_signaled(cursor->fence) &&  in dma_resv_iter_walk_unlocked()
395 		    cursor->usage >= cursor->fence_usage)  in dma_resv_iter_walk_unlocked()
401  * dma_resv_iter_first_unlocked - first fence in an unlocked dma_resv obj.
418 	} while (dma_resv_fences_list(cursor->obj) != cursor->fences);  in dma_resv_iter_first_unlocked()
421 	return cursor->fence;  in dma_resv_iter_first_unlocked()
426  * dma_resv_iter_next_unlocked - next fence in an unlocked dma_resv obj.
440 	cursor->is_restarted = false;  in dma_resv_iter_next_unlocked()
441 	restart = dma_resv_fences_list(cursor->obj) != cursor->fences;  in dma_resv_iter_next_unlocked()
447 	} while (dma_resv_fences_list(cursor->obj) != cursor->fences);  in dma_resv_iter_next_unlocked()
450 	return cursor->fence;  in dma_resv_iter_next_unlocked()
455  * dma_resv_iter_first - first fence from a locked dma_resv object
467 	dma_resv_assert_held(cursor->obj);  in dma_resv_iter_first()
469 	cursor->index = 0;  in dma_resv_iter_first()
470 	cursor->fences = dma_resv_fences_list(cursor->obj);  in dma_resv_iter_first()
473 	cursor->is_restarted = true;  in dma_resv_iter_first()
479  * dma_resv_iter_next - next fence from a locked dma_resv object
489 	dma_resv_assert_held(cursor->obj);  in dma_resv_iter_next()
491 	cursor->is_restarted = false;  in dma_resv_iter_next()
494 		if (!cursor->fences ||  in dma_resv_iter_next()
495 		    cursor->index >= cursor->fences->num_fences)  in dma_resv_iter_next()
498 		dma_resv_list_entry(cursor->fences, cursor->index++,  in dma_resv_iter_next()
499 				    cursor->obj, &fence, &cursor->fence_usage);  in dma_resv_iter_next()
500 	} while (cursor->fence_usage > cursor->usage);  in dma_resv_iter_next()
507  * dma_resv_copy_fences - Copy all fences from src to dst.
511  * Copy all fences from src to dst. dst-lock must be held.
532 				return -ENOMEM;  in dma_resv_copy_fences()
534 			list->num_fences = 0;  in dma_resv_copy_fences()
538 		dma_resv_list_set(list, list->num_fences++, f,  in dma_resv_copy_fences()
543 	list = rcu_replace_pointer(dst->fences, list, dma_resv_held(dst));  in dma_resv_copy_fences()
550  * dma_resv_get_fences - Get an object's fences
559  * Returns either zero or -ENOMEM.
578 				dma_fence_put((*fences)[--(*num_fences)]);  in dma_resv_get_fences()
582 			/* Eventually re-allocate the array */  in dma_resv_get_fences()
591 				return -ENOMEM;  in dma_resv_get_fences()
605  * dma_resv_get_singleton - Get a single fence for all the fences
611  * Returns either 0 for success or -ENOMEM.
646 		while (count--)  in dma_resv_get_singleton()
649 		return -ENOMEM;  in dma_resv_get_singleton()
652 	*fence = &array->base;  in dma_resv_get_singleton()
658  * dma_resv_wait_timeout - Wait on reservation's objects fences
667  * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
693  * dma_resv_set_deadline - Set a deadline on reservation's objects fences
716  * dma_resv_test_signaled - Test if a reservation object's fences have been
744  * dma_resv_describe - Dump description of the resv object into seq_file
775 		return -ENOMEM;  in dma_resv_lockdep()
783 	if (ret == -EDEADLK)  in dma_resv_lockdep()