tools/io_uring/io_uring-cp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Simple test program that demonstrates a file copy through io_uring. This
   4  * uses the API exposed by liburing.
   5  *
   6  * Copyright (C) 2018-2019 Jens Axboe
   7  */
   8 #include <stdio.h>
   9 #include <fcntl.h>
  10 #include <string.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <assert.h>
  14 #include <errno.h>
  15 #include <inttypes.h>
  16 #include <sys/types.h>
  17 #include <sys/stat.h>
  18 #include <sys/ioctl.h>
  19
  20 #include "liburing.h"
  21
  22 #define QD      64
  23 #define BS      (32*1024)
  24
  25 static int infd, outfd;
  26
  27 struct io_data {
  28         int read;
  29         off_t first_offset, offset;
  30         size_t first_len;
  31         struct iovec iov;
  32 };
  33
  34 static int setup_context(unsigned entries, struct io_uring *ring)
  35 {
  36         int ret;
  37
  38         ret = io_uring_queue_init(entries, ring, 0);
  39         if (ret < 0) {
  40                 fprintf(stderr, "queue_init: %s\n", strerror(-ret));
  41                 return -1;
  42         }
  43
  44         return 0;
  45 }
  46
  47 static int get_file_size(int fd, off_t *size)
  48 {
  49         struct stat st;
  50
  51         if (fstat(fd, &st) < 0)
  52                 return -1;
  53         if (S_ISREG(st.st_mode)) {
  54                 *size = st.st_size;
  55                 return 0;
  56         } else if (S_ISBLK(st.st_mode)) {
  57                 unsigned long long bytes;
  58
  59                 if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
  60                         return -1;
  61
  62                 *size = bytes;
  63                 return 0;
  64         }
  65
  66         return -1;
  67 }
  68
  69 static void queue_prepped(struct io_uring *ring, struct io_data *data)
  70 {
  71         struct io_uring_sqe *sqe;
  72
  73         sqe = io_uring_get_sqe(ring);
  74         assert(sqe);
  75
  76         if (data->read)
  77                 io_uring_prep_readv(sqe, infd, &data->iov, 1, data->offset);
  78         else
  79                 io_uring_prep_writev(sqe, outfd, &data->iov, 1, data->offset);
  80
  81         io_uring_sqe_set_data(sqe, data);
  82 }
  83
  84 static int queue_read(struct io_uring *ring, off_t size, off_t offset)
  85 {
  86         struct io_uring_sqe *sqe;
  87         struct io_data *data;
  88
  89         data = malloc(size + sizeof(*data));
  90         if (!data)
  91                 return 1;
  92
  93         sqe = io_uring_get_sqe(ring);
  94         if (!sqe) {
  95                 free(data);
  96                 return 1;
  97         }
  98
  99         data->read = 1;
 100         data->offset = data->first_offset = offset;
 101
 102         data->iov.iov_base = data + 1;
 103         data->iov.iov_len = size;
 104         data->first_len = size;
 105
 106         io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
 107         io_uring_sqe_set_data(sqe, data);
 108         return 0;
 109 }
 110
 111 static void queue_write(struct io_uring *ring, struct io_data *data)
 112 {
 113         data->read = 0;
 114         data->offset = data->first_offset;
 115
 116         data->iov.iov_base = data + 1;
 117         data->iov.iov_len = data->first_len;
 118
 119         queue_prepped(ring, data);
 120         io_uring_submit(ring);
 121 }
 122
 123 static int copy_file(struct io_uring *ring, off_t insize)
 124 {
 125         unsigned long reads, writes;
 126         struct io_uring_cqe *cqe;
 127         off_t write_left, offset;
 128         int ret;
 129
 130         write_left = insize;
 131         writes = reads = offset = 0;
 132
 133         while (insize || write_left) {
 134                 unsigned long had_reads;
 135                 int got_comp;
 136
 137                 /*
 138                  * Queue up as many reads as we can
 139                  */
 140                 had_reads = reads;
 141                 while (insize) {
 142                         off_t this_size = insize;
 143
 144                         if (reads + writes >= QD)
 145                                 break;
 146                         if (this_size > BS)
 147                                 this_size = BS;
 148                         else if (!this_size)
 149                                 break;
 150
 151                         if (queue_read(ring, this_size, offset))
 152                                 break;
 153
 154                         insize -= this_size;
 155                         offset += this_size;
 156                         reads++;
 157                 }
 158
 159                 if (had_reads != reads) {
 160                         ret = io_uring_submit(ring);
 161                         if (ret < 0) {
 162                                 fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));
 163                                 break;
 164                         }
 165                 }
 166
 167                 /*
 168                  * Queue is full at this point. Find at least one completion.
 169                  */
 170                 got_comp = 0;
 171                 while (write_left) {
 172                         struct io_data *data;
 173
 174                         if (!got_comp) {
 175                                 ret = io_uring_wait_cqe(ring, &cqe);
 176                                 got_comp = 1;
 177                         } else
 178                                 ret = io_uring_peek_cqe(ring, &cqe);
 179                         if (ret < 0) {
 180                                 fprintf(stderr, "io_uring_peek_cqe: %s\n",
 181                                                         strerror(-ret));
 182                                 return 1;
 183                         }
 184                         if (!cqe)
 185                                 break;
 186
 187                         data = io_uring_cqe_get_data(cqe);
 188                         if (cqe->res < 0) {
 189                                 if (cqe->res == -EAGAIN) {
 190                                         queue_prepped(ring, data);
 191                                         io_uring_cqe_seen(ring, cqe);
 192                                         continue;
 193                                 }
 194                                 fprintf(stderr, "cqe failed: %s\n",
 195                                                 strerror(-cqe->res));
 196                                 return 1;
 197                         } else if ((size_t) cqe->res != data->iov.iov_len) {
 198                                 /* Short read/write, adjust and requeue */
 199                                 data->iov.iov_base += cqe->res;
 200                                 data->iov.iov_len -= cqe->res;
 201                                 data->offset += cqe->res;
 202                                 queue_prepped(ring, data);
 203                                 io_uring_cqe_seen(ring, cqe);
 204                                 continue;
 205                         }
 206
 207                         /*
 208                          * All done. if write, nothing else to do. if read,
 209                          * queue up corresponding write.
 210                          */
 211                         if (data->read) {
 212                                 queue_write(ring, data);
 213                                 write_left -= data->first_len;
 214                                 reads--;
 215                                 writes++;
 216                         } else {
 217                                 free(data);
 218                                 writes--;
 219                         }
 220                         io_uring_cqe_seen(ring, cqe);
 221                 }
 222         }
 223
 224         return 0;
 225 }
 226
 227 int main(int argc, char *argv[])
 228 {
 229         struct io_uring ring;
 230         off_t insize;
 231         int ret;
 232
 233         if (argc < 3) {
 234                 printf("%s: infile outfile\n", argv[0]);
 235                 return 1;
 236         }
 237
 238         infd = open(argv[1], O_RDONLY);
 239         if (infd < 0) {
 240                 perror("open infile");
 241                 return 1;
 242         }
 243         outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
 244         if (outfd < 0) {
 245                 perror("open outfile");
 246                 return 1;
 247         }
 248
 249         if (setup_context(QD, &ring))
 250                 return 1;
 251         if (get_file_size(infd, &insize))
 252                 return 1;
 253
 254         ret = copy_file(&ring, insize);
 255
 256         close(infd);
 257         close(outfd);
 258         io_uring_queue_exit(&ring);
 259         return ret;
 260 }