814 lines · c
1// SPDX-License-Identifier: MIT2/*3 * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)4 *5 * Based on bo.c which bears the following copyright notice,6 * but is dual licensed:7 *8 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA9 * All Rights Reserved.10 *11 * Permission is hereby granted, free of charge, to any person obtaining a12 * copy of this software and associated documentation files (the13 * "Software"), to deal in the Software without restriction, including14 * without limitation the rights to use, copy, modify, merge, publish,15 * distribute, sub license, and/or sell copies of the Software, and to16 * permit persons to whom the Software is furnished to do so, subject to17 * the following conditions:18 *19 * The above copyright notice and this permission notice (including the20 * next paragraph) shall be included in all copies or substantial portions21 * of the Software.22 *23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,25 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL26 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,27 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR28 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE29 * USE OR OTHER DEALINGS IN THE SOFTWARE.30 *31 **************************************************************************/32/*33 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>34 */35 36#include <linux/dma-resv.h>37#include <linux/dma-fence-array.h>38#include <linux/export.h>39#include <linux/mm.h>40#include <linux/sched/mm.h>41#include <linux/mmu_notifier.h>42#include <linux/seq_file.h>43 44/**45 * DOC: Reservation Object Overview46 *47 * The reservation object provides a mechanism to manage a container of48 * dma_fence object associated with a resource. A reservation object49 * can have any number of fences attaches to it. Each fence carries an usage50 * parameter determining how the operation represented by the fence is using the51 * resource. The RCU mechanism is used to protect read access to fences from52 * locked write-side updates.53 *54 * See struct dma_resv for more details.55 */56 57DEFINE_WD_CLASS(reservation_ww_class);58EXPORT_SYMBOL(reservation_ww_class);59 60/* Mask for the lower fence pointer bits */61#define DMA_RESV_LIST_MASK 0x362 63struct dma_resv_list {64 struct rcu_head rcu;65 u32 num_fences, max_fences;66 struct dma_fence __rcu *table[];67};68 69/* Extract the fence and usage flags from an RCU protected entry in the list. */70static void dma_resv_list_entry(struct dma_resv_list *list, unsigned int index,71 struct dma_resv *resv, struct dma_fence **fence,72 enum dma_resv_usage *usage)73{74 long tmp;75 76 tmp = (long)rcu_dereference_check(list->table[index],77 resv ? dma_resv_held(resv) : true);78 *fence = (struct dma_fence *)(tmp & ~DMA_RESV_LIST_MASK);79 if (usage)80 *usage = tmp & DMA_RESV_LIST_MASK;81}82 83/* Set the fence and usage flags at the specific index in the list. */84static void dma_resv_list_set(struct dma_resv_list *list,85 unsigned int index,86 struct dma_fence *fence,87 enum dma_resv_usage usage)88{89 long tmp = ((long)fence) | usage;90 91 RCU_INIT_POINTER(list->table[index], (struct dma_fence *)tmp);92}93 94/*95 * Allocate a new dma_resv_list and make sure to correctly initialize96 * max_fences.97 */98static struct dma_resv_list *dma_resv_list_alloc(unsigned int max_fences)99{100 struct dma_resv_list *list;101 size_t size;102 103 /* Round up to the next kmalloc bucket size. */104 size = kmalloc_size_roundup(struct_size(list, table, max_fences));105 106 list = kmalloc(size, GFP_KERNEL);107 if (!list)108 return NULL;109 110 /* Given the resulting bucket size, recalculated max_fences. */111 list->max_fences = (size - offsetof(typeof(*list), table)) /112 sizeof(*list->table);113 114 return list;115}116 117/* Free a dma_resv_list and make sure to drop all references. */118static void dma_resv_list_free(struct dma_resv_list *list)119{120 unsigned int i;121 122 if (!list)123 return;124 125 for (i = 0; i < list->num_fences; ++i) {126 struct dma_fence *fence;127 128 dma_resv_list_entry(list, i, NULL, &fence, NULL);129 dma_fence_put(fence);130 }131 kfree_rcu(list, rcu);132}133 134/**135 * dma_resv_init - initialize a reservation object136 * @obj: the reservation object137 */138void dma_resv_init(struct dma_resv *obj)139{140 ww_mutex_init(&obj->lock, &reservation_ww_class);141 142 RCU_INIT_POINTER(obj->fences, NULL);143}144EXPORT_SYMBOL(dma_resv_init);145 146/**147 * dma_resv_fini - destroys a reservation object148 * @obj: the reservation object149 */150void dma_resv_fini(struct dma_resv *obj)151{152 /*153 * This object should be dead and all references must have154 * been released to it, so no need to be protected with rcu.155 */156 dma_resv_list_free(rcu_dereference_protected(obj->fences, true));157 ww_mutex_destroy(&obj->lock);158}159EXPORT_SYMBOL(dma_resv_fini);160 161/* Dereference the fences while ensuring RCU rules */162static inline struct dma_resv_list *dma_resv_fences_list(struct dma_resv *obj)163{164 return rcu_dereference_check(obj->fences, dma_resv_held(obj));165}166 167/**168 * dma_resv_reserve_fences - Reserve space to add fences to a dma_resv object.169 * @obj: reservation object170 * @num_fences: number of fences we want to add171 *172 * Should be called before dma_resv_add_fence(). Must be called with @obj173 * locked through dma_resv_lock().174 *175 * Note that the preallocated slots need to be re-reserved if @obj is unlocked176 * at any time before calling dma_resv_add_fence(). This is validated when177 * CONFIG_DEBUG_MUTEXES is enabled.178 *179 * RETURNS180 * Zero for success, or -errno181 */182int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences)183{184 struct dma_resv_list *old, *new;185 unsigned int i, j, k, max;186 187 dma_resv_assert_held(obj);188 189 /* Driver and component code should never call this function with190 * num_fences=0. If they do it usually points to bugs when calculating191 * the number of needed fences dynamically.192 */193 if (WARN_ON(!num_fences))194 return -EINVAL;195 196 old = dma_resv_fences_list(obj);197 if (old && old->max_fences) {198 if ((old->num_fences + num_fences) <= old->max_fences)199 return 0;200 max = max(old->num_fences + num_fences, old->max_fences * 2);201 } else {202 max = max(4ul, roundup_pow_of_two(num_fences));203 }204 205 new = dma_resv_list_alloc(max);206 if (!new)207 return -ENOMEM;208 209 /*210 * no need to bump fence refcounts, rcu_read access211 * requires the use of kref_get_unless_zero, and the212 * references from the old struct are carried over to213 * the new.214 */215 for (i = 0, j = 0, k = max; i < (old ? old->num_fences : 0); ++i) {216 enum dma_resv_usage usage;217 struct dma_fence *fence;218 219 dma_resv_list_entry(old, i, obj, &fence, &usage);220 if (dma_fence_is_signaled(fence))221 RCU_INIT_POINTER(new->table[--k], fence);222 else223 dma_resv_list_set(new, j++, fence, usage);224 }225 new->num_fences = j;226 227 /*228 * We are not changing the effective set of fences here so can229 * merely update the pointer to the new array; both existing230 * readers and new readers will see exactly the same set of231 * active (unsignaled) fences. Individual fences and the232 * old array are protected by RCU and so will not vanish under233 * the gaze of the rcu_read_lock() readers.234 */235 rcu_assign_pointer(obj->fences, new);236 237 if (!old)238 return 0;239 240 /* Drop the references to the signaled fences */241 for (i = k; i < max; ++i) {242 struct dma_fence *fence;243 244 fence = rcu_dereference_protected(new->table[i],245 dma_resv_held(obj));246 dma_fence_put(fence);247 }248 kfree_rcu(old, rcu);249 250 return 0;251}252EXPORT_SYMBOL(dma_resv_reserve_fences);253 254#ifdef CONFIG_DEBUG_MUTEXES255/**256 * dma_resv_reset_max_fences - reset fences for debugging257 * @obj: the dma_resv object to reset258 *259 * Reset the number of pre-reserved fence slots to test that drivers do260 * correct slot allocation using dma_resv_reserve_fences(). See also261 * &dma_resv_list.max_fences.262 */263void dma_resv_reset_max_fences(struct dma_resv *obj)264{265 struct dma_resv_list *fences = dma_resv_fences_list(obj);266 267 dma_resv_assert_held(obj);268 269 /* Test fence slot reservation */270 if (fences)271 fences->max_fences = fences->num_fences;272}273EXPORT_SYMBOL(dma_resv_reset_max_fences);274#endif275 276/**277 * dma_resv_add_fence - Add a fence to the dma_resv obj278 * @obj: the reservation object279 * @fence: the fence to add280 * @usage: how the fence is used, see enum dma_resv_usage281 *282 * Add a fence to a slot, @obj must be locked with dma_resv_lock(), and283 * dma_resv_reserve_fences() has been called.284 *285 * See also &dma_resv.fence for a discussion of the semantics.286 */287void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,288 enum dma_resv_usage usage)289{290 struct dma_resv_list *fobj;291 struct dma_fence *old;292 unsigned int i, count;293 294 dma_fence_get(fence);295 296 dma_resv_assert_held(obj);297 298 /* Drivers should not add containers here, instead add each fence299 * individually.300 */301 WARN_ON(dma_fence_is_container(fence));302 303 fobj = dma_resv_fences_list(obj);304 count = fobj->num_fences;305 306 for (i = 0; i < count; ++i) {307 enum dma_resv_usage old_usage;308 309 dma_resv_list_entry(fobj, i, obj, &old, &old_usage);310 if ((old->context == fence->context && old_usage >= usage &&311 dma_fence_is_later_or_same(fence, old)) ||312 dma_fence_is_signaled(old)) {313 dma_resv_list_set(fobj, i, fence, usage);314 dma_fence_put(old);315 return;316 }317 }318 319 BUG_ON(fobj->num_fences >= fobj->max_fences);320 count++;321 322 dma_resv_list_set(fobj, i, fence, usage);323 /* pointer update must be visible before we extend the num_fences */324 smp_store_mb(fobj->num_fences, count);325}326EXPORT_SYMBOL(dma_resv_add_fence);327 328/**329 * dma_resv_replace_fences - replace fences in the dma_resv obj330 * @obj: the reservation object331 * @context: the context of the fences to replace332 * @replacement: the new fence to use instead333 * @usage: how the new fence is used, see enum dma_resv_usage334 *335 * Replace fences with a specified context with a new fence. Only valid if the336 * operation represented by the original fence has no longer access to the337 * resources represented by the dma_resv object when the new fence completes.338 *339 * And example for using this is replacing a preemption fence with a page table340 * update fence which makes the resource inaccessible.341 */342void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,343 struct dma_fence *replacement,344 enum dma_resv_usage usage)345{346 struct dma_resv_list *list;347 unsigned int i;348 349 dma_resv_assert_held(obj);350 351 list = dma_resv_fences_list(obj);352 for (i = 0; list && i < list->num_fences; ++i) {353 struct dma_fence *old;354 355 dma_resv_list_entry(list, i, obj, &old, NULL);356 if (old->context != context)357 continue;358 359 dma_resv_list_set(list, i, dma_fence_get(replacement), usage);360 dma_fence_put(old);361 }362}363EXPORT_SYMBOL(dma_resv_replace_fences);364 365/* Restart the unlocked iteration by initializing the cursor object. */366static void dma_resv_iter_restart_unlocked(struct dma_resv_iter *cursor)367{368 cursor->index = 0;369 cursor->num_fences = 0;370 cursor->fences = dma_resv_fences_list(cursor->obj);371 if (cursor->fences)372 cursor->num_fences = cursor->fences->num_fences;373 cursor->is_restarted = true;374}375 376/* Walk to the next not signaled fence and grab a reference to it */377static void dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor)378{379 if (!cursor->fences)380 return;381 382 do {383 /* Drop the reference from the previous round */384 dma_fence_put(cursor->fence);385 386 if (cursor->index >= cursor->num_fences) {387 cursor->fence = NULL;388 break;389 390 }391 392 dma_resv_list_entry(cursor->fences, cursor->index++,393 cursor->obj, &cursor->fence,394 &cursor->fence_usage);395 cursor->fence = dma_fence_get_rcu(cursor->fence);396 if (!cursor->fence) {397 dma_resv_iter_restart_unlocked(cursor);398 continue;399 }400 401 if (!dma_fence_is_signaled(cursor->fence) &&402 cursor->usage >= cursor->fence_usage)403 break;404 } while (true);405}406 407/**408 * dma_resv_iter_first_unlocked - first fence in an unlocked dma_resv obj.409 * @cursor: the cursor with the current position410 *411 * Subsequent fences are iterated with dma_resv_iter_next_unlocked().412 *413 * Beware that the iterator can be restarted. Code which accumulates statistics414 * or similar needs to check for this with dma_resv_iter_is_restarted(). For415 * this reason prefer the locked dma_resv_iter_first() whenever possible.416 *417 * Returns the first fence from an unlocked dma_resv obj.418 */419struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor)420{421 rcu_read_lock();422 do {423 dma_resv_iter_restart_unlocked(cursor);424 dma_resv_iter_walk_unlocked(cursor);425 } while (dma_resv_fences_list(cursor->obj) != cursor->fences);426 rcu_read_unlock();427 428 return cursor->fence;429}430EXPORT_SYMBOL(dma_resv_iter_first_unlocked);431 432/**433 * dma_resv_iter_next_unlocked - next fence in an unlocked dma_resv obj.434 * @cursor: the cursor with the current position435 *436 * Beware that the iterator can be restarted. Code which accumulates statistics437 * or similar needs to check for this with dma_resv_iter_is_restarted(). For438 * this reason prefer the locked dma_resv_iter_next() whenever possible.439 *440 * Returns the next fence from an unlocked dma_resv obj.441 */442struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor)443{444 bool restart;445 446 rcu_read_lock();447 cursor->is_restarted = false;448 restart = dma_resv_fences_list(cursor->obj) != cursor->fences;449 do {450 if (restart)451 dma_resv_iter_restart_unlocked(cursor);452 dma_resv_iter_walk_unlocked(cursor);453 restart = true;454 } while (dma_resv_fences_list(cursor->obj) != cursor->fences);455 rcu_read_unlock();456 457 return cursor->fence;458}459EXPORT_SYMBOL(dma_resv_iter_next_unlocked);460 461/**462 * dma_resv_iter_first - first fence from a locked dma_resv object463 * @cursor: cursor to record the current position464 *465 * Subsequent fences are iterated with dma_resv_iter_next_unlocked().466 *467 * Return the first fence in the dma_resv object while holding the468 * &dma_resv.lock.469 */470struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor)471{472 struct dma_fence *fence;473 474 dma_resv_assert_held(cursor->obj);475 476 cursor->index = 0;477 cursor->fences = dma_resv_fences_list(cursor->obj);478 479 fence = dma_resv_iter_next(cursor);480 cursor->is_restarted = true;481 return fence;482}483EXPORT_SYMBOL_GPL(dma_resv_iter_first);484 485/**486 * dma_resv_iter_next - next fence from a locked dma_resv object487 * @cursor: cursor to record the current position488 *489 * Return the next fences from the dma_resv object while holding the490 * &dma_resv.lock.491 */492struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor)493{494 struct dma_fence *fence;495 496 dma_resv_assert_held(cursor->obj);497 498 cursor->is_restarted = false;499 500 do {501 if (!cursor->fences ||502 cursor->index >= cursor->fences->num_fences)503 return NULL;504 505 dma_resv_list_entry(cursor->fences, cursor->index++,506 cursor->obj, &fence, &cursor->fence_usage);507 } while (cursor->fence_usage > cursor->usage);508 509 return fence;510}511EXPORT_SYMBOL_GPL(dma_resv_iter_next);512 513/**514 * dma_resv_copy_fences - Copy all fences from src to dst.515 * @dst: the destination reservation object516 * @src: the source reservation object517 *518 * Copy all fences from src to dst. dst-lock must be held.519 */520int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)521{522 struct dma_resv_iter cursor;523 struct dma_resv_list *list;524 struct dma_fence *f;525 526 dma_resv_assert_held(dst);527 528 list = NULL;529 530 dma_resv_iter_begin(&cursor, src, DMA_RESV_USAGE_BOOKKEEP);531 dma_resv_for_each_fence_unlocked(&cursor, f) {532 533 if (dma_resv_iter_is_restarted(&cursor)) {534 dma_resv_list_free(list);535 536 list = dma_resv_list_alloc(cursor.num_fences);537 if (!list) {538 dma_resv_iter_end(&cursor);539 return -ENOMEM;540 }541 list->num_fences = 0;542 }543 544 dma_fence_get(f);545 dma_resv_list_set(list, list->num_fences++, f,546 dma_resv_iter_usage(&cursor));547 }548 dma_resv_iter_end(&cursor);549 550 list = rcu_replace_pointer(dst->fences, list, dma_resv_held(dst));551 dma_resv_list_free(list);552 return 0;553}554EXPORT_SYMBOL(dma_resv_copy_fences);555 556/**557 * dma_resv_get_fences - Get an object's fences558 * fences without update side lock held559 * @obj: the reservation object560 * @usage: controls which fences to include, see enum dma_resv_usage.561 * @num_fences: the number of fences returned562 * @fences: the array of fence ptrs returned (array is krealloc'd to the563 * required size, and must be freed by caller)564 *565 * Retrieve all fences from the reservation object.566 * Returns either zero or -ENOMEM.567 */568int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage,569 unsigned int *num_fences, struct dma_fence ***fences)570{571 struct dma_resv_iter cursor;572 struct dma_fence *fence;573 574 *num_fences = 0;575 *fences = NULL;576 577 dma_resv_iter_begin(&cursor, obj, usage);578 dma_resv_for_each_fence_unlocked(&cursor, fence) {579 580 if (dma_resv_iter_is_restarted(&cursor)) {581 struct dma_fence **new_fences;582 unsigned int count;583 584 while (*num_fences)585 dma_fence_put((*fences)[--(*num_fences)]);586 587 count = cursor.num_fences + 1;588 589 /* Eventually re-allocate the array */590 new_fences = krealloc_array(*fences, count,591 sizeof(void *),592 GFP_KERNEL);593 if (count && !new_fences) {594 kfree(*fences);595 *fences = NULL;596 *num_fences = 0;597 dma_resv_iter_end(&cursor);598 return -ENOMEM;599 }600 *fences = new_fences;601 }602 603 (*fences)[(*num_fences)++] = dma_fence_get(fence);604 }605 dma_resv_iter_end(&cursor);606 607 return 0;608}609EXPORT_SYMBOL_GPL(dma_resv_get_fences);610 611/**612 * dma_resv_get_singleton - Get a single fence for all the fences613 * @obj: the reservation object614 * @usage: controls which fences to include, see enum dma_resv_usage.615 * @fence: the resulting fence616 *617 * Get a single fence representing all the fences inside the resv object.618 * Returns either 0 for success or -ENOMEM.619 *620 * Warning: This can't be used like this when adding the fence back to the resv621 * object since that can lead to stack corruption when finalizing the622 * dma_fence_array.623 *624 * Returns 0 on success and negative error values on failure.625 */626int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,627 struct dma_fence **fence)628{629 struct dma_fence_array *array;630 struct dma_fence **fences;631 unsigned count;632 int r;633 634 r = dma_resv_get_fences(obj, usage, &count, &fences);635 if (r)636 return r;637 638 if (count == 0) {639 *fence = NULL;640 return 0;641 }642 643 if (count == 1) {644 *fence = fences[0];645 kfree(fences);646 return 0;647 }648 649 array = dma_fence_array_create(count, fences,650 dma_fence_context_alloc(1),651 1, false);652 if (!array) {653 while (count--)654 dma_fence_put(fences[count]);655 kfree(fences);656 return -ENOMEM;657 }658 659 *fence = &array->base;660 return 0;661}662EXPORT_SYMBOL_GPL(dma_resv_get_singleton);663 664/**665 * dma_resv_wait_timeout - Wait on reservation's objects fences666 * @obj: the reservation object667 * @usage: controls which fences to include, see enum dma_resv_usage.668 * @intr: if true, do interruptible wait669 * @timeout: timeout value in jiffies or zero to return immediately670 *671 * Callers are not required to hold specific locks, but maybe hold672 * dma_resv_lock() already673 * RETURNS674 * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or675 * greater than zero on success.676 */677long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,678 bool intr, unsigned long timeout)679{680 long ret = timeout ? timeout : 1;681 struct dma_resv_iter cursor;682 struct dma_fence *fence;683 684 dma_resv_iter_begin(&cursor, obj, usage);685 dma_resv_for_each_fence_unlocked(&cursor, fence) {686 687 ret = dma_fence_wait_timeout(fence, intr, ret);688 if (ret <= 0) {689 dma_resv_iter_end(&cursor);690 return ret;691 }692 }693 dma_resv_iter_end(&cursor);694 695 return ret;696}697EXPORT_SYMBOL_GPL(dma_resv_wait_timeout);698 699/**700 * dma_resv_set_deadline - Set a deadline on reservation's objects fences701 * @obj: the reservation object702 * @usage: controls which fences to include, see enum dma_resv_usage.703 * @deadline: the requested deadline (MONOTONIC)704 *705 * May be called without holding the dma_resv lock. Sets @deadline on706 * all fences filtered by @usage.707 */708void dma_resv_set_deadline(struct dma_resv *obj, enum dma_resv_usage usage,709 ktime_t deadline)710{711 struct dma_resv_iter cursor;712 struct dma_fence *fence;713 714 dma_resv_iter_begin(&cursor, obj, usage);715 dma_resv_for_each_fence_unlocked(&cursor, fence) {716 dma_fence_set_deadline(fence, deadline);717 }718 dma_resv_iter_end(&cursor);719}720EXPORT_SYMBOL_GPL(dma_resv_set_deadline);721 722/**723 * dma_resv_test_signaled - Test if a reservation object's fences have been724 * signaled.725 * @obj: the reservation object726 * @usage: controls which fences to include, see enum dma_resv_usage.727 *728 * Callers are not required to hold specific locks, but maybe hold729 * dma_resv_lock() already.730 *731 * RETURNS732 *733 * True if all fences signaled, else false.734 */735bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage)736{737 struct dma_resv_iter cursor;738 struct dma_fence *fence;739 740 dma_resv_iter_begin(&cursor, obj, usage);741 dma_resv_for_each_fence_unlocked(&cursor, fence) {742 dma_resv_iter_end(&cursor);743 return false;744 }745 dma_resv_iter_end(&cursor);746 return true;747}748EXPORT_SYMBOL_GPL(dma_resv_test_signaled);749 750/**751 * dma_resv_describe - Dump description of the resv object into seq_file752 * @obj: the reservation object753 * @seq: the seq_file to dump the description into754 *755 * Dump a textual description of the fences inside an dma_resv object into the756 * seq_file.757 */758void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq)759{760 static const char *usage[] = { "kernel", "write", "read", "bookkeep" };761 struct dma_resv_iter cursor;762 struct dma_fence *fence;763 764 dma_resv_for_each_fence(&cursor, obj, DMA_RESV_USAGE_READ, fence) {765 seq_printf(seq, "\t%s fence:",766 usage[dma_resv_iter_usage(&cursor)]);767 dma_fence_describe(fence, seq);768 }769}770EXPORT_SYMBOL_GPL(dma_resv_describe);771 772#if IS_ENABLED(CONFIG_LOCKDEP)773static int __init dma_resv_lockdep(void)774{775 struct mm_struct *mm = mm_alloc();776 struct ww_acquire_ctx ctx;777 struct dma_resv obj;778 struct address_space mapping;779 int ret;780 781 if (!mm)782 return -ENOMEM;783 784 dma_resv_init(&obj);785 address_space_init_once(&mapping);786 787 mmap_read_lock(mm);788 ww_acquire_init(&ctx, &reservation_ww_class);789 ret = dma_resv_lock(&obj, &ctx);790 if (ret == -EDEADLK)791 dma_resv_lock_slow(&obj, &ctx);792 fs_reclaim_acquire(GFP_KERNEL);793 /* for unmap_mapping_range on trylocked buffer objects in shrinkers */794 i_mmap_lock_write(&mapping);795 i_mmap_unlock_write(&mapping);796#ifdef CONFIG_MMU_NOTIFIER797 lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);798 __dma_fence_might_wait();799 lock_map_release(&__mmu_notifier_invalidate_range_start_map);800#else801 __dma_fence_might_wait();802#endif803 fs_reclaim_release(GFP_KERNEL);804 ww_mutex_unlock(&obj.lock);805 ww_acquire_fini(&ctx);806 mmap_read_unlock(mm);807 808 mmput(mm);809 810 return 0;811}812subsys_initcall(dma_resv_lockdep);813#endif814