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