| /* |
| * Header file for reservations for dma-buf and ttm |
| * |
| * Copyright(C) 2011 Linaro Limited. All rights reserved. |
| * Copyright (C) 2012-2013 Canonical Ltd |
| * Copyright (C) 2012 Texas Instruments |
| * |
| * Authors: |
| * Rob Clark <robdclark@gmail.com> |
| * Maarten Lankhorst <maarten.lankhorst@canonical.com> |
| * Thomas Hellstrom <thellstrom-at-vmware-dot-com> |
| * |
| * 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. |
| */ |
| #ifndef _LINUX_RESERVATION_H |
| #define _LINUX_RESERVATION_H |
| |
| #include <linux/ww_mutex.h> |
| #include <linux/fence.h> |
| #include <linux/slab.h> |
| #include <linux/seqlock.h> |
| #include <linux/rcupdate.h> |
| |
| extern struct ww_class reservation_ww_class; |
| extern struct lock_class_key reservation_seqcount_class; |
| extern const char reservation_seqcount_string[]; |
| |
| /** |
| * struct reservation_object_list - a list of shared fences |
| * @rcu: for internal use |
| * @shared_count: table of shared fences |
| * @shared_max: for growing shared fence table |
| * @shared: shared fence table |
| */ |
| struct reservation_object_list { |
| struct rcu_head rcu; |
| u32 shared_count, shared_max; |
| struct fence __rcu *shared[]; |
| }; |
| |
| /** |
| * struct reservation_object - a reservation object manages fences for a buffer |
| * @lock: update side lock |
| * @seq: sequence count for managing RCU read-side synchronization |
| * @fence_excl: the exclusive fence, if there is one currently |
| * @fence: list of current shared fences |
| * @staged: staged copy of shared fences for RCU updates |
| */ |
| struct reservation_object { |
| struct ww_mutex lock; |
| seqcount_t seq; |
| |
| struct fence __rcu *fence_excl; |
| struct reservation_object_list __rcu *fence; |
| struct reservation_object_list *staged; |
| }; |
| |
| #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base) |
| #define reservation_object_assert_held(obj) \ |
| lockdep_assert_held(&(obj)->lock.base) |
| |
| /** |
| * reservation_object_init - initialize a reservation object |
| * @obj: the reservation object |
| */ |
| static inline void |
| reservation_object_init(struct reservation_object *obj) |
| { |
| ww_mutex_init(&obj->lock, &reservation_ww_class); |
| |
| __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class); |
| RCU_INIT_POINTER(obj->fence, NULL); |
| RCU_INIT_POINTER(obj->fence_excl, NULL); |
| obj->staged = NULL; |
| } |
| |
| /** |
| * reservation_object_fini - destroys a reservation object |
| * @obj: the reservation object |
| */ |
| static inline void |
| reservation_object_fini(struct reservation_object *obj) |
| { |
| int i; |
| struct reservation_object_list *fobj; |
| struct fence *excl; |
| |
| /* |
| * This object should be dead and all references must have |
| * been released to it, so no need to be protected with rcu. |
| */ |
| excl = rcu_dereference_protected(obj->fence_excl, 1); |
| if (excl) |
| fence_put(excl); |
| |
| fobj = rcu_dereference_protected(obj->fence, 1); |
| if (fobj) { |
| for (i = 0; i < fobj->shared_count; ++i) |
| fence_put(rcu_dereference_protected(fobj->shared[i], 1)); |
| |
| kfree(fobj); |
| } |
| kfree(obj->staged); |
| |
| ww_mutex_destroy(&obj->lock); |
| } |
| |
| /** |
| * reservation_object_get_list - get the reservation object's |
| * shared fence list, with update-side lock held |
| * @obj: the reservation object |
| * |
| * Returns the shared fence list. Does NOT take references to |
| * the fence. The obj->lock must be held. |
| */ |
| static inline struct reservation_object_list * |
| reservation_object_get_list(struct reservation_object *obj) |
| { |
| return rcu_dereference_protected(obj->fence, |
| reservation_object_held(obj)); |
| } |
| |
| /** |
| * reservation_object_get_excl - get the reservation object's |
| * exclusive fence, with update-side lock held |
| * @obj: the reservation object |
| * |
| * Returns the exclusive fence (if any). Does NOT take a |
| * reference. The obj->lock must be held. |
| * |
| * RETURNS |
| * The exclusive fence or NULL |
| */ |
| static inline struct fence * |
| reservation_object_get_excl(struct reservation_object *obj) |
| { |
| return rcu_dereference_protected(obj->fence_excl, |
| reservation_object_held(obj)); |
| } |
| |
| /** |
| * reservation_object_get_excl_rcu - get the reservation object's |
| * exclusive fence, without lock held. |
| * @obj: the reservation object |
| * |
| * If there is an exclusive fence, this atomically increments it's |
| * reference count and returns it. |
| * |
| * RETURNS |
| * The exclusive fence or NULL if none |
| */ |
| static inline struct fence * |
| reservation_object_get_excl_rcu(struct reservation_object *obj) |
| { |
| struct fence *fence; |
| |
| if (!rcu_access_pointer(obj->fence_excl)) |
| return NULL; |
| |
| rcu_read_lock(); |
| fence = fence_get_rcu_safe(&obj->fence_excl); |
| rcu_read_unlock(); |
| |
| return fence; |
| } |
| |
| int reservation_object_reserve_shared(struct reservation_object *obj); |
| void reservation_object_add_shared_fence(struct reservation_object *obj, |
| struct fence *fence); |
| |
| void reservation_object_add_excl_fence(struct reservation_object *obj, |
| struct fence *fence); |
| |
| int reservation_object_get_fences_rcu(struct reservation_object *obj, |
| struct fence **pfence_excl, |
| unsigned *pshared_count, |
| struct fence ***pshared); |
| |
| long reservation_object_wait_timeout_rcu(struct reservation_object *obj, |
| bool wait_all, bool intr, |
| unsigned long timeout); |
| |
| bool reservation_object_test_signaled_rcu(struct reservation_object *obj, |
| bool test_all); |
| |
| #endif /* _LINUX_RESERVATION_H */ |