107 lines
2.7 KiB
C
107 lines
2.7 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause
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* Copyright(c) 2010-2014 Intel Corporation
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*/
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/**
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* @internal when c11 memory model enabled use c11 atomic memory barrier.
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* when under non c11 memory model use rte_smp_* memory barrier.
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*
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* @param src
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* Pointer to the source data.
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* @param dst
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* Pointer to the destination data.
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* @param value
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* Data value.
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*/
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#ifdef RTE_USE_C11_MEM_MODEL
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#define __KNI_LOAD_ACQUIRE(src) ({ \
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__atomic_load_n((src), __ATOMIC_ACQUIRE); \
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})
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#define __KNI_STORE_RELEASE(dst, value) do { \
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__atomic_store_n((dst), value, __ATOMIC_RELEASE); \
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} while(0)
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#else
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#define __KNI_LOAD_ACQUIRE(src) ({ \
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typeof (*(src)) val = *(src); \
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rte_smp_rmb(); \
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val; \
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})
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#define __KNI_STORE_RELEASE(dst, value) do { \
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*(dst) = value; \
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rte_smp_wmb(); \
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} while(0)
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#endif
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/**
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* Initializes the kni fifo structure
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*/
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static void
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kni_fifo_init(struct rte_kni_fifo *fifo, unsigned size)
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{
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/* Ensure size is power of 2 */
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if (size & (size - 1))
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rte_panic("KNI fifo size must be power of 2\n");
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fifo->write = 0;
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fifo->read = 0;
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fifo->len = size;
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fifo->elem_size = sizeof(void *);
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}
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/**
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* Adds num elements into the fifo. Return the number actually written
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*/
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static inline unsigned
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kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)
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{
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unsigned i = 0;
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unsigned fifo_write = fifo->write;
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unsigned new_write = fifo_write;
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unsigned fifo_read = __KNI_LOAD_ACQUIRE(&fifo->read);
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for (i = 0; i < num; i++) {
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new_write = (new_write + 1) & (fifo->len - 1);
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if (new_write == fifo_read)
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break;
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fifo->buffer[fifo_write] = data[i];
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fifo_write = new_write;
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}
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__KNI_STORE_RELEASE(&fifo->write, fifo_write);
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return i;
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}
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/**
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* Get up to num elements from the fifo. Return the number actually read
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*/
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static inline unsigned
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kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)
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{
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unsigned i = 0;
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unsigned new_read = fifo->read;
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unsigned fifo_write = __KNI_LOAD_ACQUIRE(&fifo->write);
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for (i = 0; i < num; i++) {
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if (new_read == fifo_write)
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break;
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data[i] = fifo->buffer[new_read];
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new_read = (new_read + 1) & (fifo->len - 1);
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}
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__KNI_STORE_RELEASE(&fifo->read, new_read);
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return i;
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}
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/**
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* Get the num of elements in the fifo
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*/
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static inline uint32_t
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kni_fifo_count(struct rte_kni_fifo *fifo)
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{
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unsigned fifo_write = __KNI_LOAD_ACQUIRE(&fifo->write);
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unsigned fifo_read = __KNI_LOAD_ACQUIRE(&fifo->read);
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return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1);
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}
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