2 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
3 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
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:
11 * Redistribution and use in source and binary forms, with or
12 * without modification, are permitted provided that the following
15 * - Redistributions of source code must retain the above
16 * copyright notice, this list of conditions and the following
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.
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
37 /* implements a simple circular buffer that can optionally be
38 * shared between user space and the kernel and can be resized
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
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
58 struct rxe_queue_buf {
71 struct rxe_queue_buf *buf;
72 struct rxe_mmap_info *ip;
75 unsigned int log2_elem_size;
76 unsigned int index_mask;
79 int do_mmap_info(struct rxe_dev *rxe,
80 struct mminfo __user *outbuf,
81 struct ib_ucontext *context,
82 struct rxe_queue_buf *buf,
84 struct rxe_mmap_info **ip_p);
86 void rxe_queue_reset(struct rxe_queue *q);
88 struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe,
90 unsigned int elem_size);
92 int rxe_queue_resize(struct rxe_queue *q,
93 unsigned int *num_elem_p,
94 unsigned int elem_size,
95 struct ib_ucontext *context,
96 struct mminfo __user *outbuf,
97 /* Protect producers while resizing queue */
98 spinlock_t *producer_lock,
99 /* Protect consumers while resizing queue */
100 spinlock_t *consumer_lock);
102 void rxe_queue_cleanup(struct rxe_queue *queue);
104 static inline int next_index(struct rxe_queue *q, int index)
106 return (index + 1) & q->buf->index_mask;
109 static inline int queue_empty(struct rxe_queue *q)
111 return ((q->buf->producer_index - q->buf->consumer_index)
112 & q->index_mask) == 0;
115 static inline int queue_full(struct rxe_queue *q)
117 return ((q->buf->producer_index + 1 - q->buf->consumer_index)
118 & q->index_mask) == 0;
121 static inline void advance_producer(struct rxe_queue *q)
123 q->buf->producer_index = (q->buf->producer_index + 1)
127 static inline void advance_consumer(struct rxe_queue *q)
129 q->buf->consumer_index = (q->buf->consumer_index + 1)
133 static inline void *producer_addr(struct rxe_queue *q)
135 return q->buf->data + ((q->buf->producer_index & q->index_mask)
136 << q->log2_elem_size);
139 static inline void *consumer_addr(struct rxe_queue *q)
141 return q->buf->data + ((q->buf->consumer_index & q->index_mask)
142 << q->log2_elem_size);
145 static inline unsigned int producer_index(struct rxe_queue *q)
147 return q->buf->producer_index;
150 static inline unsigned int consumer_index(struct rxe_queue *q)
152 return q->buf->consumer_index;
155 static inline void *addr_from_index(struct rxe_queue *q, unsigned int index)
157 return q->buf->data + ((index & q->index_mask)
158 << q->buf->log2_elem_size);
161 static inline unsigned int index_from_addr(const struct rxe_queue *q,
164 return (((u8 *)addr - q->buf->data) >> q->log2_elem_size)
168 static inline unsigned int queue_count(const struct rxe_queue *q)
170 return (q->buf->producer_index - q->buf->consumer_index)
174 static inline void *queue_head(struct rxe_queue *q)
176 return queue_empty(q) ? NULL : consumer_addr(q);
179 #endif /* RXE_QUEUE_H */