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/*
* Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
* Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef RXE_QUEUE_H
#define RXE_QUEUE_H
/* implements a simple circular buffer that can optionally be
* shared between user space and the kernel and can be resized
* the requested element size is rounded up to a power of 2
* and the number of elements in the buffer is also rounded
* up to a power of 2. Since the queue is empty when the
* producer and consumer indices match the maximum capacity
* of the queue is one less than the number of element slots
*/
/* this data structure is shared between user space and kernel
* space for those cases where the queue is shared. It contains
* the producer and consumer indices. Is also contains a copy
* of the queue size parameters for user space to use but the
* kernel must use the parameters in the rxe_queue struct
* this MUST MATCH the corresponding librxe struct
* for performance reasons arrange to have producer and consumer
* pointers in separate cache lines
* the kernel should always mask the indices to avoid accessing
* memory outside of the data area
*/
struct rxe_queue_buf {
__u32 log2_elem_size;
__u32 index_mask;
__u32 pad_1[30];
__u32 producer_index;
__u32 pad_2[31];
__u32 consumer_index;
__u32 pad_3[31];
__u8 data[0];
};
struct rxe_queue {
struct rxe_dev *rxe;
struct rxe_queue_buf *buf;
struct rxe_mmap_info *ip;
size_t buf_size;
size_t elem_size;
unsigned int log2_elem_size;
unsigned int index_mask;
};
int do_mmap_info(struct rxe_dev *rxe,
struct ib_udata *udata,
bool is_req,
struct ib_ucontext *context,
struct rxe_queue_buf *buf,
size_t buf_size,
struct rxe_mmap_info **ip_p);
struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe,
int *num_elem,
unsigned int elem_size);
int rxe_queue_resize(struct rxe_queue *q,
unsigned int *num_elem_p,
unsigned int elem_size,
struct ib_ucontext *context,
struct ib_udata *udata,
/* Protect producers while resizing queue */
spinlock_t *producer_lock,
/* Protect consumers while resizing queue */
spinlock_t *consumer_lock);
void rxe_queue_cleanup(struct rxe_queue *queue);
static inline int next_index(struct rxe_queue *q, int index)
{
return (index + 1) & q->buf->index_mask;
}
static inline int queue_empty(struct rxe_queue *q)
{
return ((q->buf->producer_index - q->buf->consumer_index)
& q->index_mask) == 0;
}
static inline int queue_full(struct rxe_queue *q)
{
return ((q->buf->producer_index + 1 - q->buf->consumer_index)
& q->index_mask) == 0;
}
static inline void advance_producer(struct rxe_queue *q)
{
q->buf->producer_index = (q->buf->producer_index + 1)
& q->index_mask;
}
static inline void advance_consumer(struct rxe_queue *q)
{
q->buf->consumer_index = (q->buf->consumer_index + 1)
& q->index_mask;
}
static inline void *producer_addr(struct rxe_queue *q)
{
return q->buf->data + ((q->buf->producer_index & q->index_mask)
<< q->log2_elem_size);
}
static inline void *consumer_addr(struct rxe_queue *q)
{
return q->buf->data + ((q->buf->consumer_index & q->index_mask)
<< q->log2_elem_size);
}
static inline unsigned int producer_index(struct rxe_queue *q)
{
return q->buf->producer_index;
}
static inline unsigned int consumer_index(struct rxe_queue *q)
{
return q->buf->consumer_index;
}
static inline void *addr_from_index(struct rxe_queue *q, unsigned int index)
{
return q->buf->data + ((index & q->index_mask)
<< q->buf->log2_elem_size);
}
static inline unsigned int index_from_addr(const struct rxe_queue *q,
const void *addr)
{
return (((u8 *)addr - q->buf->data) >> q->log2_elem_size)
& q->index_mask;
}
static inline unsigned int queue_count(const struct rxe_queue *q)
{
return (q->buf->producer_index - q->buf->consumer_index)
& q->index_mask;
}
static inline void *queue_head(struct rxe_queue *q)
{
return queue_empty(q) ? NULL : consumer_addr(q);
}
#endif /* RXE_QUEUE_H */
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