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/*-
* GPL LICENSE SUMMARY
*
* Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
* The full GNU General Public License is included in this distribution
* in the file called LICENSE.GPL.
*
* Contact Information:
* Intel Corporation
*/
#ifndef _KNI_FIFO_H_
#define _KNI_FIFO_H_
#include <exec-env/rte_kni_common.h>
/* Skip some memory barriers on Linux < 3.14 */
#ifndef smp_load_acquire
#define smp_load_acquire(a) (*(a))
#endif
#ifndef smp_store_release
#define smp_store_release(a, b) *(a) = (b)
#endif
/**
* Adds num elements into the fifo. Return the number actually written
*/
static inline uint32_t
kni_fifo_put(struct rte_kni_fifo *fifo, void **data, uint32_t num)
{
uint32_t i = 0;
uint32_t fifo_write = fifo->write;
uint32_t fifo_read = smp_load_acquire(&fifo->read);
uint32_t new_write = fifo_write;
for (i = 0; i < num; i++) {
new_write = (new_write + 1) & (fifo->len - 1);
if (new_write == fifo_read)
break;
fifo->buffer[fifo_write] = data[i];
fifo_write = new_write;
}
smp_store_release(&fifo->write, fifo_write);
return i;
}
/**
* Get up to num elements from the fifo. Return the number actully read
*/
static inline uint32_t
kni_fifo_get(struct rte_kni_fifo *fifo, void **data, uint32_t num)
{
uint32_t i = 0;
uint32_t new_read = fifo->read;
uint32_t fifo_write = smp_load_acquire(&fifo->write);
for (i = 0; i < num; i++) {
if (new_read == fifo_write)
break;
data[i] = fifo->buffer[new_read];
new_read = (new_read + 1) & (fifo->len - 1);
}
smp_store_release(&fifo->read, new_read);
return i;
}
/**
* Get the num of elements in the fifo
*/
static inline uint32_t
kni_fifo_count(struct rte_kni_fifo *fifo)
{
uint32_t fifo_write = smp_load_acquire(&fifo->write);
uint32_t fifo_read = smp_load_acquire(&fifo->read);
return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1);
}
/**
* Get the num of available elements in the fifo
*/
static inline uint32_t
kni_fifo_free_count(struct rte_kni_fifo *fifo)
{
uint32_t fifo_write = smp_load_acquire(&fifo->write);
uint32_t fifo_read = smp_load_acquire(&fifo->read);
return (fifo_read - fifo_write - 1) & (fifo->len - 1);
}
#ifdef RTE_KNI_VHOST
/**
* Initializes the kni fifo structure
*/
static inline void
kni_fifo_init(struct rte_kni_fifo *fifo, uint32_t size)
{
fifo->write = 0;
fifo->read = 0;
fifo->len = size;
fifo->elem_size = sizeof(void *);
}
#endif
#endif /* _KNI_FIFO_H_ */
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