Branch data     Line data    Source code

       1                 :            : /*
       2                 :            :  * Header file for reservations for dma-buf and ttm
       3                 :            :  *
       4                 :            :  * Copyright(C) 2011 Linaro Limited. All rights reserved.
       5                 :            :  * Copyright (C) 2012-2013 Canonical Ltd
       6                 :            :  * Copyright (C) 2012 Texas Instruments
       7                 :            :  *
       8                 :            :  * Authors:
       9                 :            :  * Rob Clark <robdclark@gmail.com>
      10                 :            :  * Maarten Lankhorst <maarten.lankhorst@canonical.com>
      11                 :            :  * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
      12                 :            :  *
      13                 :            :  * Based on bo.c which bears the following copyright notice,
      14                 :            :  * but is dual licensed:
      15                 :            :  *
      16                 :            :  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
      17                 :            :  * All Rights Reserved.
      18                 :            :  *
      19                 :            :  * Permission is hereby granted, free of charge, to any person obtaining a
      20                 :            :  * copy of this software and associated documentation files (the
      21                 :            :  * "Software"), to deal in the Software without restriction, including
      22                 :            :  * without limitation the rights to use, copy, modify, merge, publish,
      23                 :            :  * distribute, sub license, and/or sell copies of the Software, and to
      24                 :            :  * permit persons to whom the Software is furnished to do so, subject to
      25                 :            :  * the following conditions:
      26                 :            :  *
      27                 :            :  * The above copyright notice and this permission notice (including the
      28                 :            :  * next paragraph) shall be included in all copies or substantial portions
      29                 :            :  * of the Software.
      30                 :            :  *
      31                 :            :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
      32                 :            :  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      33                 :            :  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
      34                 :            :  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
      35                 :            :  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
      36                 :            :  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
      37                 :            :  * USE OR OTHER DEALINGS IN THE SOFTWARE.
      38                 :            :  */
      39                 :            : #ifndef _LINUX_RESERVATION_H
      40                 :            : #define _LINUX_RESERVATION_H
      41                 :            : 
      42                 :            : #include <linux/ww_mutex.h>
      43                 :            : #include <linux/dma-fence.h>
      44                 :            : #include <linux/slab.h>
      45                 :            : #include <linux/seqlock.h>
      46                 :            : #include <linux/rcupdate.h>
      47                 :            : 
      48                 :            : extern struct ww_class reservation_ww_class;
      49                 :            : extern struct lock_class_key reservation_seqcount_class;
      50                 :            : extern const char reservation_seqcount_string[];
      51                 :            : 
      52                 :            : /**
      53                 :            :  * struct dma_resv_list - a list of shared fences
      54                 :            :  * @rcu: for internal use
      55                 :            :  * @shared_count: table of shared fences
      56                 :            :  * @shared_max: for growing shared fence table
      57                 :            :  * @shared: shared fence table
      58                 :            :  */
      59                 :            : struct dma_resv_list {
      60                 :            :         struct rcu_head rcu;
      61                 :            :         u32 shared_count, shared_max;
      62                 :            :         struct dma_fence __rcu *shared[];
      63                 :            : };
      64                 :            : 
      65                 :            : /**
      66                 :            :  * struct dma_resv - a reservation object manages fences for a buffer
      67                 :            :  * @lock: update side lock
      68                 :            :  * @seq: sequence count for managing RCU read-side synchronization
      69                 :            :  * @fence_excl: the exclusive fence, if there is one currently
      70                 :            :  * @fence: list of current shared fences
      71                 :            :  */
      72                 :            : struct dma_resv {
      73                 :            :         struct ww_mutex lock;
      74                 :            :         seqcount_t seq;
      75                 :            : 
      76                 :            :         struct dma_fence __rcu *fence_excl;
      77                 :            :         struct dma_resv_list __rcu *fence;
      78                 :            : };
      79                 :            : 
      80                 :            : #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
      81                 :            : #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
      82                 :            : 
      83                 :            : /**
      84                 :            :  * dma_resv_get_list - get the reservation object's
      85                 :            :  * shared fence list, with update-side lock held
      86                 :            :  * @obj: the reservation object
      87                 :            :  *
      88                 :            :  * Returns the shared fence list.  Does NOT take references to
      89                 :            :  * the fence.  The obj->lock must be held.
      90                 :            :  */
      91                 :            : static inline struct dma_resv_list *dma_resv_get_list(struct dma_resv *obj)
      92                 :            : {
      93                 :          0 :         return rcu_dereference_protected(obj->fence,
      94                 :            :                                          dma_resv_held(obj));
      95                 :            : }
      96                 :            : 
      97                 :            : /**
      98                 :            :  * dma_resv_lock - lock the reservation object
      99                 :            :  * @obj: the reservation object
     100                 :            :  * @ctx: the locking context
     101                 :            :  *
     102                 :            :  * Locks the reservation object for exclusive access and modification. Note,
     103                 :            :  * that the lock is only against other writers, readers will run concurrently
     104                 :            :  * with a writer under RCU. The seqlock is used to notify readers if they
     105                 :            :  * overlap with a writer.
     106                 :            :  *
     107                 :            :  * As the reservation object may be locked by multiple parties in an
     108                 :            :  * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
     109                 :            :  * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
     110                 :            :  * object may be locked by itself by passing NULL as @ctx.
     111                 :            :  */
     112                 :            : static inline int dma_resv_lock(struct dma_resv *obj,
     113                 :            :                                 struct ww_acquire_ctx *ctx)
     114                 :            : {
     115                 :            :         return ww_mutex_lock(&obj->lock, ctx);
     116                 :            : }
     117                 :            : 
     118                 :            : /**
     119                 :            :  * dma_resv_lock_interruptible - lock the reservation object
     120                 :            :  * @obj: the reservation object
     121                 :            :  * @ctx: the locking context
     122                 :            :  *
     123                 :            :  * Locks the reservation object interruptible for exclusive access and
     124                 :            :  * modification. Note, that the lock is only against other writers, readers
     125                 :            :  * will run concurrently with a writer under RCU. The seqlock is used to
     126                 :            :  * notify readers if they overlap with a writer.
     127                 :            :  *
     128                 :            :  * As the reservation object may be locked by multiple parties in an
     129                 :            :  * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
     130                 :            :  * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
     131                 :            :  * object may be locked by itself by passing NULL as @ctx.
     132                 :            :  */
     133                 :            : static inline int dma_resv_lock_interruptible(struct dma_resv *obj,
     134                 :            :                                               struct ww_acquire_ctx *ctx)
     135                 :            : {
     136                 :            :         return ww_mutex_lock_interruptible(&obj->lock, ctx);
     137                 :            : }
     138                 :            : 
     139                 :            : /**
     140                 :            :  * dma_resv_lock_slow - slowpath lock the reservation object
     141                 :            :  * @obj: the reservation object
     142                 :            :  * @ctx: the locking context
     143                 :            :  *
     144                 :            :  * Acquires the reservation object after a die case. This function
     145                 :            :  * will sleep until the lock becomes available. See dma_resv_lock() as
     146                 :            :  * well.
     147                 :            :  */
     148                 :            : static inline void dma_resv_lock_slow(struct dma_resv *obj,
     149                 :            :                                       struct ww_acquire_ctx *ctx)
     150                 :            : {
     151                 :            :         ww_mutex_lock_slow(&obj->lock, ctx);
     152                 :            : }
     153                 :            : 
     154                 :            : /**
     155                 :            :  * dma_resv_lock_slow_interruptible - slowpath lock the reservation
     156                 :            :  * object, interruptible
     157                 :            :  * @obj: the reservation object
     158                 :            :  * @ctx: the locking context
     159                 :            :  *
     160                 :            :  * Acquires the reservation object interruptible after a die case. This function
     161                 :            :  * will sleep until the lock becomes available. See
     162                 :            :  * dma_resv_lock_interruptible() as well.
     163                 :            :  */
     164                 :            : static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj,
     165                 :            :                                                    struct ww_acquire_ctx *ctx)
     166                 :            : {
     167                 :            :         return ww_mutex_lock_slow_interruptible(&obj->lock, ctx);
     168                 :            : }
     169                 :            : 
     170                 :            : /**
     171                 :            :  * dma_resv_trylock - trylock the reservation object
     172                 :            :  * @obj: the reservation object
     173                 :            :  *
     174                 :            :  * Tries to lock the reservation object for exclusive access and modification.
     175                 :            :  * Note, that the lock is only against other writers, readers will run
     176                 :            :  * concurrently with a writer under RCU. The seqlock is used to notify readers
     177                 :            :  * if they overlap with a writer.
     178                 :            :  *
     179                 :            :  * Also note that since no context is provided, no deadlock protection is
     180                 :            :  * possible.
     181                 :            :  *
     182                 :            :  * Returns true if the lock was acquired, false otherwise.
     183                 :            :  */
     184                 :            : static inline bool __must_check dma_resv_trylock(struct dma_resv *obj)
     185                 :            : {
     186                 :            :         return ww_mutex_trylock(&obj->lock);
     187                 :            : }
     188                 :            : 
     189                 :            : /**
     190                 :            :  * dma_resv_is_locked - is the reservation object locked
     191                 :            :  * @obj: the reservation object
     192                 :            :  *
     193                 :            :  * Returns true if the mutex is locked, false if unlocked.
     194                 :            :  */
     195                 :            : static inline bool dma_resv_is_locked(struct dma_resv *obj)
     196                 :            : {
     197                 :            :         return ww_mutex_is_locked(&obj->lock);
     198                 :            : }
     199                 :            : 
     200                 :            : /**
     201                 :            :  * dma_resv_locking_ctx - returns the context used to lock the object
     202                 :            :  * @obj: the reservation object
     203                 :            :  *
     204                 :            :  * Returns the context used to lock a reservation object or NULL if no context
     205                 :            :  * was used or the object is not locked at all.
     206                 :            :  */
     207                 :            : static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
     208                 :            : {
     209                 :            :         return READ_ONCE(obj->lock.ctx);
     210                 :            : }
     211                 :            : 
     212                 :            : /**
     213                 :            :  * dma_resv_unlock - unlock the reservation object
     214                 :            :  * @obj: the reservation object
     215                 :            :  *
     216                 :            :  * Unlocks the reservation object following exclusive access.
     217                 :            :  */
     218                 :            : static inline void dma_resv_unlock(struct dma_resv *obj)
     219                 :            : {
     220                 :            : #ifdef CONFIG_DEBUG_MUTEXES
     221                 :            :         /* Test shared fence slot reservation */
     222                 :            :         if (rcu_access_pointer(obj->fence)) {
     223                 :            :                 struct dma_resv_list *fence = dma_resv_get_list(obj);
     224                 :            : 
     225                 :            :                 fence->shared_max = fence->shared_count;
     226                 :            :         }
     227                 :            : #endif
     228                 :            :         ww_mutex_unlock(&obj->lock);
     229                 :            : }
     230                 :            : 
     231                 :            : /**
     232                 :            :  * dma_resv_get_excl - get the reservation object's
     233                 :            :  * exclusive fence, with update-side lock held
     234                 :            :  * @obj: the reservation object
     235                 :            :  *
     236                 :            :  * Returns the exclusive fence (if any).  Does NOT take a
     237                 :            :  * reference. Writers must hold obj->lock, readers may only
     238                 :            :  * hold a RCU read side lock.
     239                 :            :  *
     240                 :            :  * RETURNS
     241                 :            :  * The exclusive fence or NULL
     242                 :            :  */
     243                 :            : static inline struct dma_fence *
     244                 :            : dma_resv_get_excl(struct dma_resv *obj)
     245                 :            : {
     246                 :          0 :         return rcu_dereference_protected(obj->fence_excl,
     247                 :            :                                          dma_resv_held(obj));
     248                 :            : }
     249                 :            : 
     250                 :            : /**
     251                 :            :  * dma_resv_get_excl_rcu - get the reservation object's
     252                 :            :  * exclusive fence, without lock held.
     253                 :            :  * @obj: the reservation object
     254                 :            :  *
     255                 :            :  * If there is an exclusive fence, this atomically increments it's
     256                 :            :  * reference count and returns it.
     257                 :            :  *
     258                 :            :  * RETURNS
     259                 :            :  * The exclusive fence or NULL if none
     260                 :            :  */
     261                 :            : static inline struct dma_fence *
     262                 :            : dma_resv_get_excl_rcu(struct dma_resv *obj)
     263                 :            : {
     264                 :            :         struct dma_fence *fence;
     265                 :            : 
     266                 :            :         if (!rcu_access_pointer(obj->fence_excl))
     267                 :            :                 return NULL;
     268                 :            : 
     269                 :            :         rcu_read_lock();
     270                 :            :         fence = dma_fence_get_rcu_safe(&obj->fence_excl);
     271                 :            :         rcu_read_unlock();
     272                 :            : 
     273                 :            :         return fence;
     274                 :            : }
     275                 :            : 
     276                 :            : void dma_resv_init(struct dma_resv *obj);
     277                 :            : void dma_resv_fini(struct dma_resv *obj);
     278                 :            : int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
     279                 :            : void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence);
     280                 :            : 
     281                 :            : void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);
     282                 :            : 
     283                 :            : int dma_resv_get_fences_rcu(struct dma_resv *obj,
     284                 :            :                             struct dma_fence **pfence_excl,
     285                 :            :                             unsigned *pshared_count,
     286                 :            :                             struct dma_fence ***pshared);
     287                 :            : 
     288                 :            : int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
     289                 :            : 
     290                 :            : long dma_resv_wait_timeout_rcu(struct dma_resv *obj, bool wait_all, bool intr,
     291                 :            :                                unsigned long timeout);
     292                 :            : 
     293                 :            : bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all);
     294                 :            : 
     295                 :            : #endif /* _LINUX_RESERVATION_H */