~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/include/drm/drm_modeset_lock.h

Version: ~ [ linux-6.1-rc7 ] ~ [ linux-6.0.10 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.80 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.156 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.225 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.267 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.300 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.334 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.302 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (C) 2014 Red Hat
  3  * Author: Rob Clark <robdclark@gmail.com>
  4  *
  5  * Permission is hereby granted, free of charge, to any person obtaining a
  6  * copy of this software and associated documentation files (the "Software"),
  7  * to deal in the Software without restriction, including without limitation
  8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  9  * and/or sell copies of the Software, and to permit persons to whom the
 10  * Software is furnished to do so, subject to the following conditions:
 11  *
 12  * The above copyright notice and this permission notice shall be included in
 13  * all copies or substantial portions of the Software.
 14  *
 15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 18  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 19  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 20  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 21  * OTHER DEALINGS IN THE SOFTWARE.
 22  */
 23 
 24 #ifndef DRM_MODESET_LOCK_H_
 25 #define DRM_MODESET_LOCK_H_
 26 
 27 #include <linux/ww_mutex.h>
 28 
 29 struct drm_modeset_lock;
 30 
 31 /**
 32  * struct drm_modeset_acquire_ctx - locking context (see ww_acquire_ctx)
 33  * @ww_ctx: base acquire ctx
 34  * @contended: used internally for -EDEADLK handling
 35  * @locked: list of held locks
 36  * @trylock_only: trylock mode used in atomic contexts/panic notifiers
 37  * @interruptible: whether interruptible locking should be used.
 38  *
 39  * Each thread competing for a set of locks must use one acquire
 40  * ctx.  And if any lock fxn returns -EDEADLK, it must backoff and
 41  * retry.
 42  */
 43 struct drm_modeset_acquire_ctx {
 44 
 45         struct ww_acquire_ctx ww_ctx;
 46 
 47         /*
 48          * Contended lock: if a lock is contended you should only call
 49          * drm_modeset_backoff() which drops locks and slow-locks the
 50          * contended lock.
 51          */
 52         struct drm_modeset_lock *contended;
 53 
 54         /*
 55          * list of held locks (drm_modeset_lock)
 56          */
 57         struct list_head locked;
 58 
 59         /*
 60          * Trylock mode, use only for panic handlers!
 61          */
 62         bool trylock_only;
 63 
 64         /* Perform interruptible waits on this context. */
 65         bool interruptible;
 66 };
 67 
 68 /**
 69  * struct drm_modeset_lock - used for locking modeset resources.
 70  * @mutex: resource locking
 71  * @head: used to hold it's place on &drm_atomi_state.locked list when
 72  *    part of an atomic update
 73  *
 74  * Used for locking CRTCs and other modeset resources.
 75  */
 76 struct drm_modeset_lock {
 77         /*
 78          * modeset lock
 79          */
 80         struct ww_mutex mutex;
 81 
 82         /*
 83          * Resources that are locked as part of an atomic update are added
 84          * to a list (so we know what to unlock at the end).
 85          */
 86         struct list_head head;
 87 };
 88 
 89 #define DRM_MODESET_ACQUIRE_INTERRUPTIBLE BIT(0)
 90 
 91 void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx,
 92                 uint32_t flags);
 93 void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx);
 94 void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx);
 95 int drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx);
 96 
 97 void drm_modeset_lock_init(struct drm_modeset_lock *lock);
 98 
 99 /**
100  * drm_modeset_lock_fini - cleanup lock
101  * @lock: lock to cleanup
102  */
103 static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock)
104 {
105         WARN_ON(!list_empty(&lock->head));
106 }
107 
108 /**
109  * drm_modeset_is_locked - equivalent to mutex_is_locked()
110  * @lock: lock to check
111  */
112 static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock)
113 {
114         return ww_mutex_is_locked(&lock->mutex);
115 }
116 
117 int drm_modeset_lock(struct drm_modeset_lock *lock,
118                 struct drm_modeset_acquire_ctx *ctx);
119 int __must_check drm_modeset_lock_single_interruptible(struct drm_modeset_lock *lock);
120 void drm_modeset_unlock(struct drm_modeset_lock *lock);
121 
122 struct drm_device;
123 struct drm_crtc;
124 struct drm_plane;
125 
126 void drm_modeset_lock_all(struct drm_device *dev);
127 void drm_modeset_unlock_all(struct drm_device *dev);
128 void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
129 
130 int drm_modeset_lock_all_ctx(struct drm_device *dev,
131                              struct drm_modeset_acquire_ctx *ctx);
132 
133 /**
134  * DRM_MODESET_LOCK_ALL_BEGIN - Helper to acquire modeset locks
135  * @dev: drm device
136  * @ctx: local modeset acquire context, will be dereferenced
137  * @flags: DRM_MODESET_ACQUIRE_* flags to pass to drm_modeset_acquire_init()
138  * @ret: local ret/err/etc variable to track error status
139  *
140  * Use these macros to simplify grabbing all modeset locks using a local
141  * context. This has the advantage of reducing boilerplate, but also properly
142  * checking return values where appropriate.
143  *
144  * Any code run between BEGIN and END will be holding the modeset locks.
145  *
146  * This must be paired with DRM_MODESET_LOCK_ALL_END(). We will jump back and
147  * forth between the labels on deadlock and error conditions.
148  *
149  * Drivers can acquire additional modeset locks. If any lock acquisition
150  * fails, the control flow needs to jump to DRM_MODESET_LOCK_ALL_END() with
151  * the @ret parameter containing the return value of drm_modeset_lock().
152  *
153  * Returns:
154  * The only possible value of ret immediately after DRM_MODESET_LOCK_ALL_BEGIN()
155  * is 0, so no error checking is necessary
156  */
157 #define DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, flags, ret)                \
158         drm_modeset_acquire_init(&ctx, flags);                          \
159 modeset_lock_retry:                                                     \
160         ret = drm_modeset_lock_all_ctx(dev, &ctx);                      \
161         if (ret)                                                        \
162                 goto modeset_lock_fail;
163 
164 /**
165  * DRM_MODESET_LOCK_ALL_END - Helper to release and cleanup modeset locks
166  * @ctx: local modeset acquire context, will be dereferenced
167  * @ret: local ret/err/etc variable to track error status
168  *
169  * The other side of DRM_MODESET_LOCK_ALL_BEGIN(). It will bounce back to BEGIN
170  * if ret is -EDEADLK.
171  *
172  * It's important that you use the same ret variable for begin and end so
173  * deadlock conditions are properly handled.
174  *
175  * Returns:
176  * ret will be untouched unless it is -EDEADLK on entry. That means that if you
177  * successfully acquire the locks, ret will be whatever your code sets it to. If
178  * there is a deadlock or other failure with acquire or backoff, ret will be set
179  * to that failure. In both of these cases the code between BEGIN/END will not
180  * be run, so the failure will reflect the inability to grab the locks.
181  */
182 #define DRM_MODESET_LOCK_ALL_END(ctx, ret)                              \
183 modeset_lock_fail:                                                      \
184         if (ret == -EDEADLK) {                                          \
185                 ret = drm_modeset_backoff(&ctx);                        \
186                 if (!ret)                                               \
187                         goto modeset_lock_retry;                        \
188         }                                                               \
189         drm_modeset_drop_locks(&ctx);                                   \
190         drm_modeset_acquire_fini(&ctx);
191 
192 #endif /* DRM_MODESET_LOCK_H_ */
193 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp