2 * Ringbuffer Routines for VM
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5 #include <linux/errno.h>
6 #include <linux/percpu.h>
7 #include <linux/sched.h>
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9 #include "palacios.h"
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10 #include "palacios-ringbuffer.h"
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12 void init_ringbuf(struct ringbuf * ring, unsigned int size) {
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13 ring->buf = kmalloc(size, GFP_KERNEL);
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18 ring->current_len = 0;
21 struct ringbuf * create_ringbuf(unsigned int size) {
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22 struct ringbuf * ring = (struct ringbuf *)kmalloc(sizeof(struct ringbuf), GFP_KERNEL);
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23 init_ringbuf(ring, size);
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28 void free_ringbuf(struct ringbuf * ring) {
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33 static inline unsigned char * get_read_ptr(struct ringbuf * ring) {
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34 return (unsigned char *)(ring->buf + ring->start);
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38 static inline unsigned char * get_write_ptr(struct ringbuf * ring) {
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39 return (unsigned char *)(ring->buf + ring->end);
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42 static inline int get_read_section_size(struct ringbuf * ring) {
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43 return ring->size - ring->start;
47 static inline int get_write_section_size(struct ringbuf * ring) {
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48 return ring->size - ring->end;
52 static inline int is_read_loop(struct ringbuf * ring, unsigned int len) {
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53 if ((ring->start >= ring->end) && (ring->current_len > 0)) {
54 // end is past the end of the buffer
55 if (get_read_section_size(ring) < len) {
63 static inline int is_write_loop(struct ringbuf * ring, unsigned int len) {
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64 if ((ring->end >= ring->start) && (ring->current_len < ring->size)) {
65 // end is past the end of the buffer
66 if (get_write_section_size(ring) < len) {
74 static inline int ringbuf_avail_space(struct ringbuf * ring) {
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75 return ring->size - ring->current_len;
79 int ringbuf_data_len(struct ringbuf * ring) {
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80 return ring->current_len;
84 static inline int ringbuf_capacity(struct ringbuf * ring) {
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89 int ringbuf_read(struct ringbuf * ring, unsigned char * dst, unsigned int len) {
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91 int ring_data_len = ring->current_len;
93 read_len = (len > ring_data_len) ? ring_data_len : len;
95 if (is_read_loop(ring, read_len)) {
96 int section_len = get_read_section_size(ring);
98 memcpy(dst, get_read_ptr(ring), section_len);
99 memcpy(dst + section_len, ring->buf, read_len - section_len);
101 ring->start = read_len - section_len;
103 memcpy(dst, get_read_ptr(ring), read_len);
105 ring->start += read_len;
108 ring->current_len -= read_len;
116 static int ringbuf_peek(struct ringbuf * ring, unsigned char * dst, unsigned int len) {
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118 int ring_data_len = ring->current_len;
120 read_len = (len > ring_data_len) ? ring_data_len : len;
122 if (is_read_loop(ring, read_len)) {
123 int section_len = get_read_section_size(ring);
125 memcpy(dst, get_read_ptr(ring), section_len);
126 memcpy(dst + section_len, ring->buf, read_len - section_len);
128 memcpy(dst, get_read_ptr(ring), read_len);
135 static int ringbuf_delete(struct ringbuf * ring, unsigned int len) {
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137 int ring_data_len = ring->current_len;
139 del_len = (len > ring_data_len) ? ring_data_len : len;
141 if (is_read_loop(ring, del_len)) {
142 int section_len = get_read_section_size(ring);
143 ring->start = del_len - section_len;
145 ring->start += del_len;
148 ring->current_len -= del_len;
153 int ringbuf_write(struct ringbuf * ring, unsigned char * src, unsigned int len) {
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155 int ring_avail_space = ring->size - ring->current_len;
157 write_len = (len > ring_avail_space) ? ring_avail_space : len;
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159 if (is_write_loop(ring, write_len)) {
160 int section_len = get_write_section_size(ring);
162 memcpy(get_write_ptr(ring), src, section_len);
165 memcpy(get_write_ptr(ring), src + section_len, write_len - section_len);
167 ring->end += write_len - section_len;
169 memcpy(get_write_ptr(ring), src, write_len);
171 ring->end += write_len;
174 ring->current_len += write_len;