2 * Ringbuffer implementation
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7 #include <linux/errno.h>
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8 #include <linux/percpu.h>
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9 #include <linux/sched.h>
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11 #include "palacios.h"
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12 #include "util-ringbuffer.h"
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14 void init_ringbuf(struct ringbuf * ring, unsigned int size) {
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15 ring->buf = kmalloc(size, GFP_KERNEL);
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20 ring->current_len = 0;
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23 struct ringbuf * create_ringbuf(unsigned int size) {
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24 struct ringbuf * ring = (struct ringbuf *)kmalloc(sizeof(struct ringbuf), GFP_KERNEL);
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25 init_ringbuf(ring, size);
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30 void free_ringbuf(struct ringbuf * ring) {
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35 static inline unsigned char * get_read_ptr(struct ringbuf * ring) {
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36 return (unsigned char *)(ring->buf + ring->start);
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40 static inline unsigned char * get_write_ptr(struct ringbuf * ring) {
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41 return (unsigned char *)(ring->buf + ring->end);
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44 static inline int get_read_section_size(struct ringbuf * ring) {
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45 return ring->size - ring->start;
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49 static inline int get_write_section_size(struct ringbuf * ring) {
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50 return ring->size - ring->end;
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54 static inline int is_read_loop(struct ringbuf * ring, unsigned int len) {
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55 if ((ring->start >= ring->end) && (ring->current_len > 0)) {
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56 // end is past the end of the buffer
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57 if (get_read_section_size(ring) < len) {
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65 static inline int is_write_loop(struct ringbuf * ring, unsigned int len) {
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66 if ((ring->end >= ring->start) && (ring->current_len < ring->size)) {
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67 // end is past the end of the buffer
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68 if (get_write_section_size(ring) < len) {
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76 static inline int ringbuf_avail_space(struct ringbuf * ring) {
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77 return ring->size - ring->current_len;
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81 int ringbuf_data_len(struct ringbuf * ring) {
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82 return ring->current_len;
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86 static inline int ringbuf_capacity(struct ringbuf * ring) {
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91 int ringbuf_read(struct ringbuf * ring, unsigned char * dst, unsigned int len) {
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93 int ring_data_len = ring->current_len;
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95 read_len = (len > ring_data_len) ? ring_data_len : len;
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97 if (is_read_loop(ring, read_len)) {
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98 int section_len = get_read_section_size(ring);
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100 memcpy(dst, get_read_ptr(ring), section_len);
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101 memcpy(dst + section_len, ring->buf, read_len - section_len);
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103 ring->start = read_len - section_len;
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105 memcpy(dst, get_read_ptr(ring), read_len);
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107 ring->start += read_len;
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110 ring->current_len -= read_len;
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118 static int ringbuf_peek(struct ringbuf * ring, unsigned char * dst, unsigned int len) {
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120 int ring_data_len = ring->current_len;
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122 read_len = (len > ring_data_len) ? ring_data_len : len;
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124 if (is_read_loop(ring, read_len)) {
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125 int section_len = get_read_section_size(ring);
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127 memcpy(dst, get_read_ptr(ring), section_len);
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128 memcpy(dst + section_len, ring->buf, read_len - section_len);
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130 memcpy(dst, get_read_ptr(ring), read_len);
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137 static int ringbuf_delete(struct ringbuf * ring, unsigned int len) {
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139 int ring_data_len = ring->current_len;
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141 del_len = (len > ring_data_len) ? ring_data_len : len;
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143 if (is_read_loop(ring, del_len)) {
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144 int section_len = get_read_section_size(ring);
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145 ring->start = del_len - section_len;
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147 ring->start += del_len;
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150 ring->current_len -= del_len;
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155 int ringbuf_write(struct ringbuf * ring, unsigned char * src, unsigned int len) {
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157 int ring_avail_space = ring->size - ring->current_len;
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159 write_len = (len > ring_avail_space) ? ring_avail_space : len;
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161 if (is_write_loop(ring, write_len)) {
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162 int section_len = get_write_section_size(ring);
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164 memcpy(get_write_ptr(ring), src, section_len);
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167 memcpy(get_write_ptr(ring), src + section_len, write_len - section_len);
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169 ring->end += write_len - section_len;
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171 memcpy(get_write_ptr(ring), src, write_len);
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173 ring->end += write_len;
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176 ring->current_len += write_len;
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