drivers/infiniband/sw/rxe/rxe_queue.h

   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 */