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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2010-2014 Intel Corporation
*/
/**
* @internal when c11 memory model enabled use c11 atomic memory barrier.
* when under non c11 memory model use rte_smp_* memory barrier.
*
* @param src
* Pointer to the source data.
* @param dst
* Pointer to the destination data.
* @param value
* Data value.
*/
#ifdef RTE_USE_C11_MEM_MODEL
#define __KNI_LOAD_ACQUIRE(src) ({ \
__atomic_load_n((src), __ATOMIC_ACQUIRE); \
})
#define __KNI_STORE_RELEASE(dst, value) do { \
__atomic_store_n((dst), value, __ATOMIC_RELEASE); \
} while(0)
#else
#define __KNI_LOAD_ACQUIRE(src) ({ \
typeof (*(src)) val = *(src); \
rte_smp_rmb(); \
val; \
})
#define __KNI_STORE_RELEASE(dst, value) do { \
*(dst) = value; \
rte_smp_wmb(); \
} while(0)
#endif
/**
* Initializes the kni fifo structure
*/
static void
kni_fifo_init(struct rte_kni_fifo *fifo, unsigned size)
{
/* Ensure size is power of 2 */
if (size & (size - 1))
rte_panic("KNI fifo size must be power of 2\n");
fifo->write = 0;
fifo->read = 0;
fifo->len = size;
fifo->elem_size = sizeof(void *);
}
/**
* Adds num elements into the fifo. Return the number actually written
*/
static inline unsigned
kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)
{
unsigned i = 0;
unsigned fifo_write = fifo->write;
unsigned new_write = fifo_write;
unsigned fifo_read = __KNI_LOAD_ACQUIRE(&fifo->read);
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;
}
__KNI_STORE_RELEASE(&fifo->write, fifo_write);
return i;
}
/**
* Get up to num elements from the fifo. Return the number actually read
*/
static inline unsigned
kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)
{
unsigned i = 0;
unsigned new_read = fifo->read;
unsigned fifo_write = __KNI_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);
}
__KNI_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)
{
unsigned fifo_write = __KNI_LOAD_ACQUIRE(&fifo->write);
unsigned fifo_read = __KNI_LOAD_ACQUIRE(&fifo->read);
return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1);
}
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