1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
2
3 #ifndef __DRM_EXEC_H__
4 #define __DRM_EXEC_H__
5
6 #include <linux/compiler.h>
7 #include <linux/ww_mutex.h>
8
9 #define DRM_EXEC_INTERRUPTIBLE_WAIT BIT(0)
10 #define DRM_EXEC_IGNORE_DUPLICATES BIT(1)
11
12 struct drm_gem_object;
13
14 /**
15 * struct drm_exec - Execution context
16 */
17 struct drm_exec {
18 /**
19 * @flags: Flags to control locking behavior
20 */
21 uint32_t flags;
22
23 /**
24 * @ticket: WW ticket used for acquiring locks
25 */
26 struct ww_acquire_ctx ticket;
27
28 /**
29 * @num_objects: number of objects locked
30 */
31 unsigned int num_objects;
32
33 /**
34 * @max_objects: maximum objects in array
35 */
36 unsigned int max_objects;
37
38 /**
39 * @objects: array of the locked objects
40 */
41 struct drm_gem_object **objects;
42
43 /**
44 * @contended: contended GEM object we backed off for
45 */
46 struct drm_gem_object *contended;
47
48 /**
49 * @prelocked: already locked GEM object due to contention
50 */
51 struct drm_gem_object *prelocked;
52 };
53
54 /**
55 * drm_exec_obj() - Return the object for a give drm_exec index
56 * @exec: Pointer to the drm_exec context
57 * @index: The index.
58 *
59 * Return: Pointer to the locked object corresponding to @index if
60 * index is within the number of locked objects. NULL otherwise.
61 */
62 static inline struct drm_gem_object *
drm_exec_obj(struct drm_exec * exec,unsigned long index)63 drm_exec_obj(struct drm_exec *exec, unsigned long index)
64 {
65 return index < exec->num_objects ? exec->objects[index] : NULL;
66 }
67
68 /**
69 * drm_exec_for_each_locked_object - iterate over all the locked objects
70 * @exec: drm_exec object
71 * @index: unsigned long index for the iteration
72 * @obj: the current GEM object
73 *
74 * Iterate over all the locked GEM objects inside the drm_exec object.
75 */
76 #define drm_exec_for_each_locked_object(exec, index, obj) \
77 for ((index) = 0; ((obj) = drm_exec_obj(exec, index)); ++(index))
78
79 /**
80 * drm_exec_for_each_locked_object_reverse - iterate over all the locked
81 * objects in reverse locking order
82 * @exec: drm_exec object
83 * @index: unsigned long index for the iteration
84 * @obj: the current GEM object
85 *
86 * Iterate over all the locked GEM objects inside the drm_exec object in
87 * reverse locking order. Note that @index may go below zero and wrap,
88 * but that will be caught by drm_exec_obj(), returning a NULL object.
89 */
90 #define drm_exec_for_each_locked_object_reverse(exec, index, obj) \
91 for ((index) = (exec)->num_objects - 1; \
92 ((obj) = drm_exec_obj(exec, index)); --(index))
93
94 /**
95 * drm_exec_until_all_locked - loop until all GEM objects are locked
96 * @exec: drm_exec object
97 *
98 * Core functionality of the drm_exec object. Loops until all GEM objects are
99 * locked and no more contention exists. At the beginning of the loop it is
100 * guaranteed that no GEM object is locked.
101 *
102 * Since labels can't be defined local to the loops body we use a jump pointer
103 * to make sure that the retry is only used from within the loops body.
104 */
105 #define drm_exec_until_all_locked(exec) \
106 __PASTE(__drm_exec_, __LINE__): \
107 for (void *__drm_exec_retry_ptr; ({ \
108 __drm_exec_retry_ptr = &&__PASTE(__drm_exec_, __LINE__);\
109 (void)__drm_exec_retry_ptr; \
110 drm_exec_cleanup(exec); \
111 });)
112
113 /**
114 * drm_exec_retry_on_contention - restart the loop to grap all locks
115 * @exec: drm_exec object
116 *
117 * Control flow helper to continue when a contention was detected and we need to
118 * clean up and re-start the loop to prepare all GEM objects.
119 */
120 #define drm_exec_retry_on_contention(exec) \
121 do { \
122 if (unlikely(drm_exec_is_contended(exec))) \
123 goto *__drm_exec_retry_ptr; \
124 } while (0)
125
126 /**
127 * drm_exec_is_contended - check for contention
128 * @exec: drm_exec object
129 *
130 * Returns true if the drm_exec object has run into some contention while
131 * locking a GEM object and needs to clean up.
132 */
drm_exec_is_contended(struct drm_exec * exec)133 static inline bool drm_exec_is_contended(struct drm_exec *exec)
134 {
135 return !!exec->contended;
136 }
137
138 void drm_exec_init(struct drm_exec *exec, uint32_t flags);
139 void drm_exec_fini(struct drm_exec *exec);
140 bool drm_exec_cleanup(struct drm_exec *exec);
141 int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
142 void drm_exec_unlock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
143 int drm_exec_prepare_obj(struct drm_exec *exec, struct drm_gem_object *obj,
144 unsigned int num_fences);
145 int drm_exec_prepare_array(struct drm_exec *exec,
146 struct drm_gem_object **objects,
147 unsigned int num_objects,
148 unsigned int num_fences);
149
150 #endif
151