1 /**************************************************************************
2  *
3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
4  * All Rights Reserved.
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6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
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11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
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18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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26  **************************************************************************/
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 filled in by call, or NULL if only
74  *           non-blocking reserves should be tried.
75  * @list:    thread private list of ttm_validate_buffer structs.
76  *
77  * Tries to reserve bos pointed to by the list entries for validation.
78  * If the function returns 0, all buffers are marked as "unfenced",
79  * taken off the lru lists and are not synced for write CPU usage.
80  *
81  * If the function detects a deadlock due to multiple threads trying to
82  * reserve the same buffers in reverse order, all threads except one will
83  * back off and retry. This function may sleep while waiting for
84  * CPU write reservations to be cleared, and for other threads to
85  * unreserve their buffers.
86  *
87  * This function may return -ERESTART or -EAGAIN if the calling process
88  * receives a signal while waiting. In that case, no buffers on the list
89  * will be reserved upon return.
90  *
91  * Buffers reserved by this function should be unreserved by
92  * a call to either ttm_eu_backoff_reservation() or
93  * ttm_eu_fence_buffer_objects() when command submission is complete or
94  * has failed.
95  */
96 
97 extern int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
98 				  struct list_head *list);
99 
100 /**
101  * function ttm_eu_fence_buffer_objects.
102  *
103  * @ticket:      ww_acquire_ctx from reserve call
104  * @list:        thread private list of ttm_validate_buffer structs.
105  * @sync_obj:    The new sync object for the buffers.
106  *
107  * This function should be called when command submission is complete, and
108  * it will add a new sync object to bos pointed to by entries on @list.
109  * It also unreserves all buffers, putting them on lru lists.
110  *
111  */
112 
113 extern void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
114 					struct list_head *list, void *sync_obj);
115 
116 #endif
117