1 /*
2 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
3 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
4 *
5 * This software is available to you under a choice of one of two
6 * licenses. You may choose to be licensed under the terms of the GNU
7 * General Public License (GPL) Version 2, available from the file
8 * COPYING in the main directory of this source tree, or the
9 * OpenIB.org BSD license below:
10 *
11 * Redistribution and use in source and binary forms, with or
12 * without modification, are permitted provided that the following
13 * conditions are met:
14 *
15 * - Redistributions of source code must retain the above
16 * copyright notice, this list of conditions and the following
17 * disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials
22 * provided with the distribution.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31 * SOFTWARE.
32 */
33
34 #ifndef RXE_QUEUE_H
35 #define RXE_QUEUE_H
36
37 /* implements a simple circular buffer that can optionally be
38 * shared between user space and the kernel and can be resized
39
40 * the requested element size is rounded up to a power of 2
41 * and the number of elements in the buffer is also rounded
42 * up to a power of 2. Since the queue is empty when the
43 * producer and consumer indices match the maximum capacity
44 * of the queue is one less than the number of element slots
45 */
46
47 /* this data structure is shared between user space and kernel
48 * space for those cases where the queue is shared. It contains
49 * the producer and consumer indices. Is also contains a copy
50 * of the queue size parameters for user space to use but the
51 * kernel must use the parameters in the rxe_queue struct
52 * this MUST MATCH the corresponding librxe struct
53 * for performance reasons arrange to have producer and consumer
54 * pointers in separate cache lines
55 * the kernel should always mask the indices to avoid accessing
56 * memory outside of the data area
57 */
58 struct rxe_queue_buf {
59 __u32 log2_elem_size;
60 __u32 index_mask;
61 __u32 pad_1[30];
62 __u32 producer_index;
63 __u32 pad_2[31];
64 __u32 consumer_index;
65 __u32 pad_3[31];
66 __u8 data[0];
67 };
68
69 struct rxe_queue {
70 struct rxe_dev *rxe;
71 struct rxe_queue_buf *buf;
72 struct rxe_mmap_info *ip;
73 size_t buf_size;
74 size_t elem_size;
75 unsigned int log2_elem_size;
76 unsigned int index_mask;
77 };
78
79 int do_mmap_info(struct rxe_dev *rxe, struct mminfo __user *outbuf,
80 struct ib_udata *udata, struct rxe_queue_buf *buf,
81 size_t buf_size, struct rxe_mmap_info **ip_p);
82
83 void rxe_queue_reset(struct rxe_queue *q);
84
85 struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe,
86 int *num_elem,
87 unsigned int elem_size);
88
89 int rxe_queue_resize(struct rxe_queue *q, unsigned int *num_elem_p,
90 unsigned int elem_size, struct ib_udata *udata,
91 struct mminfo __user *outbuf,
92 /* Protect producers while resizing queue */
93 spinlock_t *producer_lock,
94 /* Protect consumers while resizing queue */
95 spinlock_t *consumer_lock);
96
97 void rxe_queue_cleanup(struct rxe_queue *queue);
98
99 static inline int next_index(struct rxe_queue *q, int index)
100 {
101 return (index + 1) & q->buf->index_mask;
102 }
103
104 static inline int queue_empty(struct rxe_queue *q)
105 {
106 return ((q->buf->producer_index - q->buf->consumer_index)
107 & q->index_mask) == 0;
108 }
109
110 static inline int queue_full(struct rxe_queue *q)
111 {
112 return ((q->buf->producer_index + 1 - q->buf->consumer_index)
113 & q->index_mask) == 0;
114 }
115
116 static inline void advance_producer(struct rxe_queue *q)
117 {
118 q->buf->producer_index = (q->buf->producer_index + 1)
119 & q->index_mask;
120 }
121
122 static inline void advance_consumer(struct rxe_queue *q)
123 {
124 q->buf->consumer_index = (q->buf->consumer_index + 1)
125 & q->index_mask;
126 }
127
128 static inline void *producer_addr(struct rxe_queue *q)
129 {
130 return q->buf->data + ((q->buf->producer_index & q->index_mask)
131 << q->log2_elem_size);
132 }
133
134 static inline void *consumer_addr(struct rxe_queue *q)
135 {
136 return q->buf->data + ((q->buf->consumer_index & q->index_mask)
137 << q->log2_elem_size);
138 }
139
140 static inline unsigned int producer_index(struct rxe_queue *q)
141 {
142 return q->buf->producer_index;
143 }
144
145 static inline unsigned int consumer_index(struct rxe_queue *q)
146 {
147 return q->buf->consumer_index;
148 }
149
150 static inline void *addr_from_index(struct rxe_queue *q, unsigned int index)
151 {
152 return q->buf->data + ((index & q->index_mask)
153 << q->buf->log2_elem_size);
154 }
155
156 static inline unsigned int index_from_addr(const struct rxe_queue *q,
157 const void *addr)
158 {
159 return (((u8 *)addr - q->buf->data) >> q->log2_elem_size)
160 & q->index_mask;
161 }
162
163 static inline unsigned int queue_count(const struct rxe_queue *q)
164 {
165 return (q->buf->producer_index - q->buf->consumer_index)
166 & q->index_mask;
167 }
168
169 static inline void *queue_head(struct rxe_queue *q)
170 {
171 return queue_empty(q) ? NULL : consumer_addr(q);
172 }
173
174 #endif /* RXE_QUEUE_H */