147 lines
3.6 KiB
C
147 lines
3.6 KiB
C
/*
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* lib/circ_buf_packet.c
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*
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* Copyright (C) 2012-2017, Samsung Electronics Co., Ltd.
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*
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* Circular buffer packet operations.
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*/
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#include <linux/err.h>
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#include "lib/circ_buf.h"
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#include "lib/circ_buf_packet.h"
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struct circ_buf_packet_header {
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uint32_t packet_size;
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} __packed;
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size_t circ_buf_size_for_packet(size_t size)
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{
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return size + sizeof(struct circ_buf_packet_header);
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}
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ssize_t circ_buf_write_packet(struct circ_buf_desc *circ_buf_desc, const char *buf,
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size_t length, enum circ_buf_user_mode mode)
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{
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ssize_t ret;
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ret = circ_buf_write_packet_local(circ_buf_desc, buf, length, mode);
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if (!IS_ERR_VALUE(ret))
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circ_buf_flush_write(circ_buf_desc);
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return ret;
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}
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ssize_t circ_buf_write_packet_local(struct circ_buf_desc *circ_buf_desc, const char *buf,
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size_t length, enum circ_buf_user_mode mode)
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{
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struct circ_buf_packet_header header;
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ssize_t ret;
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unsigned int write_count_orig = circ_buf_desc->write_count;
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header.packet_size = length;
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ret = circ_buf_write_local(circ_buf_desc, (void *) &header,
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sizeof(struct circ_buf_packet_header), CIRC_BUF_MODE_KERNEL);
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if (IS_ERR_VALUE(ret))
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return ret;
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ret = circ_buf_write_local(circ_buf_desc, buf, length, mode);
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if (IS_ERR_VALUE(ret))
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circ_buf_desc->write_count = write_count_orig;
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return ret;
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}
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ssize_t circ_buf_read_packet(struct circ_buf_desc *circ_buf_desc, char *buf,
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size_t length, enum circ_buf_user_mode mode)
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{
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ssize_t ret;
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ret = circ_buf_read_packet_local(circ_buf_desc, buf, length, mode);
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if (!IS_ERR_VALUE(ret))
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circ_buf_flush_read(circ_buf_desc);
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return ret;
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}
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ssize_t circ_buf_read_packet_local(struct circ_buf_desc *circ_buf_desc, char *buf,
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size_t length, enum circ_buf_user_mode mode)
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{
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struct circ_buf_packet_header header;
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ssize_t ret;
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size_t packet_size;
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unsigned int read_count_orig = circ_buf_desc->read_count;
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ret = circ_buf_read_local(circ_buf_desc, (void *) &header,
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sizeof(struct circ_buf_packet_header), CIRC_BUF_MODE_KERNEL);
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if (IS_ERR_VALUE(ret))
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return ret;
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packet_size = header.packet_size;
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if (packet_size > length) {
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circ_buf_desc->read_count = read_count_orig;
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return -EMSGSIZE;
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}
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ret = circ_buf_read_local(circ_buf_desc, buf, packet_size, mode);
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if (IS_ERR_VALUE(ret))
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circ_buf_desc->read_count = read_count_orig;
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return ret;
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}
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ssize_t circ_buf_drop_packet(struct circ_buf_desc *circ_buf_desc)
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{
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ssize_t ret;
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ret = circ_buf_drop_packet_local(circ_buf_desc);
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if (!IS_ERR_VALUE(ret))
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circ_buf_flush_read(circ_buf_desc);
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return ret;
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}
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ssize_t circ_buf_drop_packet_local(struct circ_buf_desc *circ_buf_desc)
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{
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struct circ_buf_packet_header header;
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ssize_t ret;
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unsigned int read_count_orig = circ_buf_desc->read_count;
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ret = circ_buf_read_local(circ_buf_desc, (void *) &header,
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sizeof(struct circ_buf_packet_header), CIRC_BUF_MODE_KERNEL);
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if (IS_ERR_VALUE(ret))
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return ret;
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ret = circ_buf_read_local(circ_buf_desc, NULL, header.packet_size,
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CIRC_BUF_MODE_DROP);
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if (IS_ERR_VALUE(ret))
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circ_buf_desc->read_count = read_count_orig;
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return ret;
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}
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ssize_t circ_buf_peek_packet(struct circ_buf_desc *circ_buf_desc, char *buf,
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size_t length, size_t offset, enum circ_buf_user_mode mode)
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{
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struct circ_buf_packet_header header;
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ssize_t ret;
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unsigned int read_count_orig = circ_buf_desc->read_count;
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ret = circ_buf_read_local(circ_buf_desc, (void *) &header,
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sizeof(struct circ_buf_packet_header), CIRC_BUF_MODE_KERNEL);
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if (IS_ERR_VALUE(ret))
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return ret;
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if (offset + length > header.packet_size) {
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ret = -EMSGSIZE;
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goto out;
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}
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ret = __circ_buf_read_local(circ_buf_desc, buf, length, offset, mode);
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out:
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circ_buf_desc->read_count = read_count_orig;
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return ret;
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}
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