// SPDX-License-Identifier: MIT /* * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst) * * Based on bo.c which bears the following copyright notice, * but is dual licensed: * * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sub license, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice (including the * next paragraph) shall be included in all copies or substantial portions * of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE * USE OR OTHER DEALINGS IN THE SOFTWARE. * **************************************************************************/ /* * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> */ #include <linux/dma-resv.h> #include <linux/dma-fence-array.h> #include <linux/export.h> #include <linux/mm.h> #include <linux/sched/mm.h> #include <linux/mmu_notifier.h> #include <linux/seq_file.h> /** * DOC: Reservation Object Overview * * The reservation object provides a mechanism to manage a container of * dma_fence object associated with a resource. A reservation object * can have any number of fences attaches to it. Each fence carries an usage * parameter determining how the operation represented by the fence is using the * resource. The RCU mechanism is used to protect read access to fences from * locked write-side updates. * * See struct dma_resv for more details. */ DEFINE_WD_CLASS(…); EXPORT_SYMBOL(…); /* Mask for the lower fence pointer bits */ #define DMA_RESV_LIST_MASK … struct dma_resv_list { … }; /* Extract the fence and usage flags from an RCU protected entry in the list. */ static void dma_resv_list_entry(struct dma_resv_list *list, unsigned int index, struct dma_resv *resv, struct dma_fence **fence, enum dma_resv_usage *usage) { … } /* Set the fence and usage flags at the specific index in the list. */ static void dma_resv_list_set(struct dma_resv_list *list, unsigned int index, struct dma_fence *fence, enum dma_resv_usage usage) { … } /* * Allocate a new dma_resv_list and make sure to correctly initialize * max_fences. */ static struct dma_resv_list *dma_resv_list_alloc(unsigned int max_fences) { … } /* Free a dma_resv_list and make sure to drop all references. */ static void dma_resv_list_free(struct dma_resv_list *list) { … } /** * dma_resv_init - initialize a reservation object * @obj: the reservation object */ void dma_resv_init(struct dma_resv *obj) { … } EXPORT_SYMBOL(…); /** * dma_resv_fini - destroys a reservation object * @obj: the reservation object */ void dma_resv_fini(struct dma_resv *obj) { … } EXPORT_SYMBOL(…); /* Dereference the fences while ensuring RCU rules */ static inline struct dma_resv_list *dma_resv_fences_list(struct dma_resv *obj) { … } /** * dma_resv_reserve_fences - Reserve space to add fences to a dma_resv object. * @obj: reservation object * @num_fences: number of fences we want to add * * Should be called before dma_resv_add_fence(). Must be called with @obj * locked through dma_resv_lock(). * * Note that the preallocated slots need to be re-reserved if @obj is unlocked * at any time before calling dma_resv_add_fence(). This is validated when * CONFIG_DEBUG_MUTEXES is enabled. * * RETURNS * Zero for success, or -errno */ int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences) { … } EXPORT_SYMBOL(…); #ifdef CONFIG_DEBUG_MUTEXES /** * dma_resv_reset_max_fences - reset fences for debugging * @obj: the dma_resv object to reset * * Reset the number of pre-reserved fence slots to test that drivers do * correct slot allocation using dma_resv_reserve_fences(). See also * &dma_resv_list.max_fences. */ void dma_resv_reset_max_fences(struct dma_resv *obj) { … } EXPORT_SYMBOL(…); #endif /** * dma_resv_add_fence - Add a fence to the dma_resv obj * @obj: the reservation object * @fence: the fence to add * @usage: how the fence is used, see enum dma_resv_usage * * Add a fence to a slot, @obj must be locked with dma_resv_lock(), and * dma_resv_reserve_fences() has been called. * * See also &dma_resv.fence for a discussion of the semantics. */ void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence, enum dma_resv_usage usage) { … } EXPORT_SYMBOL(…); /** * dma_resv_replace_fences - replace fences in the dma_resv obj * @obj: the reservation object * @context: the context of the fences to replace * @replacement: the new fence to use instead * @usage: how the new fence is used, see enum dma_resv_usage * * Replace fences with a specified context with a new fence. Only valid if the * operation represented by the original fence has no longer access to the * resources represented by the dma_resv object when the new fence completes. * * And example for using this is replacing a preemption fence with a page table * update fence which makes the resource inaccessible. */ void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context, struct dma_fence *replacement, enum dma_resv_usage usage) { … } EXPORT_SYMBOL(…); /* Restart the unlocked iteration by initializing the cursor object. */ static void dma_resv_iter_restart_unlocked(struct dma_resv_iter *cursor) { … } /* Walk to the next not signaled fence and grab a reference to it */ static void dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor) { … } /** * dma_resv_iter_first_unlocked - first fence in an unlocked dma_resv obj. * @cursor: the cursor with the current position * * Subsequent fences are iterated with dma_resv_iter_next_unlocked(). * * Beware that the iterator can be restarted. Code which accumulates statistics * or similar needs to check for this with dma_resv_iter_is_restarted(). For * this reason prefer the locked dma_resv_iter_first() whenever possible. * * Returns the first fence from an unlocked dma_resv obj. */ struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor) { … } EXPORT_SYMBOL(…); /** * dma_resv_iter_next_unlocked - next fence in an unlocked dma_resv obj. * @cursor: the cursor with the current position * * Beware that the iterator can be restarted. Code which accumulates statistics * or similar needs to check for this with dma_resv_iter_is_restarted(). For * this reason prefer the locked dma_resv_iter_next() whenever possible. * * Returns the next fence from an unlocked dma_resv obj. */ struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor) { … } EXPORT_SYMBOL(…); /** * dma_resv_iter_first - first fence from a locked dma_resv object * @cursor: cursor to record the current position * * Subsequent fences are iterated with dma_resv_iter_next_unlocked(). * * Return the first fence in the dma_resv object while holding the * &dma_resv.lock. */ struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor) { … } EXPORT_SYMBOL_GPL(…); /** * dma_resv_iter_next - next fence from a locked dma_resv object * @cursor: cursor to record the current position * * Return the next fences from the dma_resv object while holding the * &dma_resv.lock. */ struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor) { … } EXPORT_SYMBOL_GPL(…); /** * dma_resv_copy_fences - Copy all fences from src to dst. * @dst: the destination reservation object * @src: the source reservation object * * Copy all fences from src to dst. dst-lock must be held. */ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src) { … } EXPORT_SYMBOL(…); /** * dma_resv_get_fences - Get an object's fences * fences without update side lock held * @obj: the reservation object * @usage: controls which fences to include, see enum dma_resv_usage. * @num_fences: the number of fences returned * @fences: the array of fence ptrs returned (array is krealloc'd to the * required size, and must be freed by caller) * * Retrieve all fences from the reservation object. * Returns either zero or -ENOMEM. */ int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage, unsigned int *num_fences, struct dma_fence ***fences) { … } EXPORT_SYMBOL_GPL(…); /** * dma_resv_get_singleton - Get a single fence for all the fences * @obj: the reservation object * @usage: controls which fences to include, see enum dma_resv_usage. * @fence: the resulting fence * * Get a single fence representing all the fences inside the resv object. * Returns either 0 for success or -ENOMEM. * * Warning: This can't be used like this when adding the fence back to the resv * object since that can lead to stack corruption when finalizing the * dma_fence_array. * * Returns 0 on success and negative error values on failure. */ int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage, struct dma_fence **fence) { … } EXPORT_SYMBOL_GPL(…); /** * dma_resv_wait_timeout - Wait on reservation's objects fences * @obj: the reservation object * @usage: controls which fences to include, see enum dma_resv_usage. * @intr: if true, do interruptible wait * @timeout: timeout value in jiffies or zero to return immediately * * Callers are not required to hold specific locks, but maybe hold * dma_resv_lock() already * RETURNS * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or * greater than zero on success. */ long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage, bool intr, unsigned long timeout) { … } EXPORT_SYMBOL_GPL(…); /** * dma_resv_set_deadline - Set a deadline on reservation's objects fences * @obj: the reservation object * @usage: controls which fences to include, see enum dma_resv_usage. * @deadline: the requested deadline (MONOTONIC) * * May be called without holding the dma_resv lock. Sets @deadline on * all fences filtered by @usage. */ void dma_resv_set_deadline(struct dma_resv *obj, enum dma_resv_usage usage, ktime_t deadline) { … } EXPORT_SYMBOL_GPL(…); /** * dma_resv_test_signaled - Test if a reservation object's fences have been * signaled. * @obj: the reservation object * @usage: controls which fences to include, see enum dma_resv_usage. * * Callers are not required to hold specific locks, but maybe hold * dma_resv_lock() already. * * RETURNS * * True if all fences signaled, else false. */ bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage) { … } EXPORT_SYMBOL_GPL(…); /** * dma_resv_describe - Dump description of the resv object into seq_file * @obj: the reservation object * @seq: the seq_file to dump the description into * * Dump a textual description of the fences inside an dma_resv object into the * seq_file. */ void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq) { … } EXPORT_SYMBOL_GPL(…); #if IS_ENABLED(CONFIG_LOCKDEP) static int __init dma_resv_lockdep(void) { … } subsys_initcall(dma_resv_lockdep); #endif
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