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// SPDX-License-Identifier: GPL-2.0
/*
* Simple test program that demonstrates a file copy through io_uring. This
* uses the API exposed by liburing.
*
* Copyright (C) 2018-2019 Jens Axboe
*/
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include "liburing.h"
#define QD 64
#define BS (32*1024)
static int infd, outfd;
struct io_data {
int read;
off_t first_offset, offset;
size_t first_len;
struct iovec iov;
};
static int setup_context(unsigned entries, struct io_uring *ring)
{
int ret;
ret = io_uring_queue_init(entries, ring, 0);
if (ret < 0) {
fprintf(stderr, "queue_init: %s\n", strerror(-ret));
return -1;
}
return 0;
}
static int get_file_size(int fd, off_t *size)
{
struct stat st;
if (fstat(fd, &st) < 0)
return -1;
if (S_ISREG(st.st_mode)) {
*size = st.st_size;
return 0;
} else if (S_ISBLK(st.st_mode)) {
unsigned long long bytes;
if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
return -1;
*size = bytes;
return 0;
}
return -1;
}
static void queue_prepped(struct io_uring *ring, struct io_data *data)
{
struct io_uring_sqe *sqe;
sqe = io_uring_get_sqe(ring);
assert(sqe);
if (data->read)
io_uring_prep_readv(sqe, infd, &data->iov, 1, data->offset);
else
io_uring_prep_writev(sqe, outfd, &data->iov, 1, data->offset);
io_uring_sqe_set_data(sqe, data);
}
static int queue_read(struct io_uring *ring, off_t size, off_t offset)
{
struct io_uring_sqe *sqe;
struct io_data *data;
sqe = io_uring_get_sqe(ring);
if (!sqe)
return 1;
data = malloc(size + sizeof(*data));
data->read = 1;
data->offset = data->first_offset = offset;
data->iov.iov_base = data + 1;
data->iov.iov_len = size;
data->first_len = size;
io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
io_uring_sqe_set_data(sqe, data);
return 0;
}
static void queue_write(struct io_uring *ring, struct io_data *data)
{
data->read = 0;
data->offset = data->first_offset;
data->iov.iov_base = data + 1;
data->iov.iov_len = data->first_len;
queue_prepped(ring, data);
io_uring_submit(ring);
}
static int copy_file(struct io_uring *ring, off_t insize)
{
unsigned long reads, writes;
struct io_uring_cqe *cqe;
off_t write_left, offset;
int ret;
write_left = insize;
writes = reads = offset = 0;
while (insize || write_left) {
unsigned long had_reads;
int got_comp;
/*
* Queue up as many reads as we can
*/
had_reads = reads;
while (insize) {
off_t this_size = insize;
if (reads + writes >= QD)
break;
if (this_size > BS)
this_size = BS;
else if (!this_size)
break;
if (queue_read(ring, this_size, offset))
break;
insize -= this_size;
offset += this_size;
reads++;
}
if (had_reads != reads) {
ret = io_uring_submit(ring);
if (ret < 0) {
fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));
break;
}
}
/*
* Queue is full at this point. Find at least one completion.
*/
got_comp = 0;
while (write_left) {
struct io_data *data;
if (!got_comp) {
ret = io_uring_wait_completion(ring, &cqe);
got_comp = 1;
} else
ret = io_uring_get_completion(ring, &cqe);
if (ret < 0) {
fprintf(stderr, "io_uring_get_completion: %s\n",
strerror(-ret));
return 1;
}
if (!cqe)
break;
data = (struct io_data *) (uintptr_t) cqe->user_data;
if (cqe->res < 0) {
if (cqe->res == -EAGAIN) {
queue_prepped(ring, data);
continue;
}
fprintf(stderr, "cqe failed: %s\n",
strerror(-cqe->res));
return 1;
} else if ((size_t) cqe->res != data->iov.iov_len) {
/* Short read/write, adjust and requeue */
data->iov.iov_base += cqe->res;
data->iov.iov_len -= cqe->res;
data->offset += cqe->res;
queue_prepped(ring, data);
continue;
}
/*
* All done. if write, nothing else to do. if read,
* queue up corresponding write.
*/
if (data->read) {
queue_write(ring, data);
write_left -= data->first_len;
reads--;
writes++;
} else {
free(data);
writes--;
}
}
}
return 0;
}
int main(int argc, char *argv[])
{
struct io_uring ring;
off_t insize;
int ret;
if (argc < 3) {
printf("%s: infile outfile\n", argv[0]);
return 1;
}
infd = open(argv[1], O_RDONLY);
if (infd < 0) {
perror("open infile");
return 1;
}
outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
if (outfd < 0) {
perror("open outfile");
return 1;
}
if (setup_context(QD, &ring))
return 1;
if (get_file_size(infd, &insize))
return 1;
ret = copy_file(&ring, insize);
close(infd);
close(outfd);
io_uring_queue_exit(&ring);
return ret;
}
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