xref: /linux/include/drm/ttm/ttm_execbuf_util.h (revision 1e1159bb97cf4191849b4b03f77ab32977c2ece6)
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27 /*
28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29  */
30 
31 #ifndef _TTM_EXECBUF_UTIL_H_
32 #define _TTM_EXECBUF_UTIL_H_
33 
34 #include <ttm/ttm_bo_api.h>
35 #include <linux/list.h>
36 
37 /**
38  * struct ttm_validate_buffer
39  *
40  * @head:           list head for thread-private list.
41  * @bo:             refcounted buffer object pointer.
42  * @reserved:       Indicates whether @bo has been reserved for validation.
43  * @removed:        Indicates whether @bo has been removed from lru lists.
44  * @put_count:      Number of outstanding references on bo::list_kref.
45  * @old_sync_obj:   Pointer to a sync object about to be unreferenced
46  */
47 
48 struct ttm_validate_buffer {
49 	struct list_head head;
50 	struct ttm_buffer_object *bo;
51 	bool reserved;
52 	bool removed;
53 	int put_count;
54 	void *old_sync_obj;
55 };
56 
57 /**
58  * function ttm_eu_backoff_reservation
59  *
60  * @ticket:   ww_acquire_ctx from reserve call
61  * @list:     thread private list of ttm_validate_buffer structs.
62  *
63  * Undoes all buffer validation reservations for bos pointed to by
64  * the list entries.
65  */
66 
67 extern void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
68 				       struct list_head *list);
69 
70 /**
71  * function ttm_eu_reserve_buffers
72  *
73  * @ticket:  [out] ww_acquire_ctx returned by call.
74  * @list:    thread private list of ttm_validate_buffer structs.
75  *
76  * Tries to reserve bos pointed to by the list entries for validation.
77  * If the function returns 0, all buffers are marked as "unfenced",
78  * taken off the lru lists and are not synced for write CPU usage.
79  *
80  * If the function detects a deadlock due to multiple threads trying to
81  * reserve the same buffers in reverse order, all threads except one will
82  * back off and retry. This function may sleep while waiting for
83  * CPU write reservations to be cleared, and for other threads to
84  * unreserve their buffers.
85  *
86  * This function may return -ERESTART or -EAGAIN if the calling process
87  * receives a signal while waiting. In that case, no buffers on the list
88  * will be reserved upon return.
89  *
90  * Buffers reserved by this function should be unreserved by
91  * a call to either ttm_eu_backoff_reservation() or
92  * ttm_eu_fence_buffer_objects() when command submission is complete or
93  * has failed.
94  */
95 
96 extern int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
97 				  struct list_head *list);
98 
99 /**
100  * function ttm_eu_fence_buffer_objects.
101  *
102  * @ticket:      ww_acquire_ctx from reserve call
103  * @list:        thread private list of ttm_validate_buffer structs.
104  * @sync_obj:    The new sync object for the buffers.
105  *
106  * This function should be called when command submission is complete, and
107  * it will add a new sync object to bos pointed to by entries on @list.
108  * It also unreserves all buffers, putting them on lru lists.
109  *
110  */
111 
112 extern void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
113 					struct list_head *list, void *sync_obj);
114 
115 #endif
116