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2  *
3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
4  * All Rights Reserved.
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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:
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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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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  * @new_sync_obj_arg: New sync_obj_arg for @bo, to be used once
43  * adding a new sync object.
44  * @reserved:       Indicates whether @bo has been reserved for validation.
45  * @removed:        Indicates whether @bo has been removed from lru lists.
46  * @put_count:      Number of outstanding references on bo::list_kref.
47  * @old_sync_obj:   Pointer to a sync object about to be unreferenced
48  */
49 
50 struct ttm_validate_buffer {
51 	struct list_head head;
52 	struct ttm_buffer_object *bo;
53 	void *new_sync_obj_arg;
54 	bool reserved;
55 	bool removed;
56 	int put_count;
57 	void *old_sync_obj;
58 };
59 
60 /**
61  * function ttm_eu_backoff_reservation
62  *
63  * @list:     thread private list of ttm_validate_buffer structs.
64  *
65  * Undoes all buffer validation reservations for bos pointed to by
66  * the list entries.
67  */
68 
69 extern void ttm_eu_backoff_reservation(struct list_head *list);
70 
71 /**
72  * function ttm_eu_reserve_buffers
73  *
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 list_head *list);
97 
98 /**
99  * function ttm_eu_fence_buffer_objects.
100  *
101  * @list:        thread private list of ttm_validate_buffer structs.
102  * @sync_obj:    The new sync object for the buffers.
103  *
104  * This function should be called when command submission is complete, and
105  * it will add a new sync object to bos pointed to by entries on @list.
106  * It also unreserves all buffers, putting them on lru lists.
107  *
108  */
109 
110 extern void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj);
111 
112 #endif
113