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/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
/*
* Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
* Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
*/
#ifndef RXE_QUEUE_H
#define RXE_QUEUE_H
/* for definition of shared struct rxe_queue_buf */
#include <uapi/rdma/rdma_user_rxe.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
*/
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;
u32 index_mask;
};
int do_mmap_info(struct rxe_dev *rxe, struct mminfo __user *outbuf,
struct ib_udata *udata, struct rxe_queue_buf *buf,
size_t buf_size, struct rxe_mmap_info **ip_p);
void rxe_queue_reset(struct rxe_queue *q);
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_udata *udata,
struct mminfo __user *outbuf,
/* 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)
{
u32 prod;
u32 cons;
/* make sure all changes to queue complete before
* testing queue empty
*/
prod = smp_load_acquire(&q->buf->producer_index);
/* same */
cons = smp_load_acquire(&q->buf->consumer_index);
return ((prod - cons) & q->index_mask) == 0;
}
static inline int queue_full(struct rxe_queue *q)
{
u32 prod;
u32 cons;
/* make sure all changes to queue complete before
* testing queue full
*/
prod = smp_load_acquire(&q->buf->producer_index);
/* same */
cons = smp_load_acquire(&q->buf->consumer_index);
return ((prod + 1 - cons) & q->index_mask) == 0;
}
static inline void advance_producer(struct rxe_queue *q)
{
u32 prod;
prod = (q->buf->producer_index + 1) & q->index_mask;
/* make sure all changes to queue complete before
* changing producer index
*/
smp_store_release(&q->buf->producer_index, prod);
}
static inline void advance_consumer(struct rxe_queue *q)
{
u32 cons;
cons = (q->buf->consumer_index + 1) & q->index_mask;
/* make sure all changes to queue complete before
* changing consumer index
*/
smp_store_release(&q->buf->consumer_index, cons);
}
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)
{
u32 index;
/* make sure all changes to queue
* complete before getting producer index
*/
index = smp_load_acquire(&q->buf->producer_index);
index &= q->index_mask;
return index;
}
static inline unsigned int consumer_index(struct rxe_queue *q)
{
u32 index;
/* make sure all changes to queue
* complete before getting consumer index
*/
index = smp_load_acquire(&q->buf->consumer_index);
index &= q->index_mask;
return 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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