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/*
* Very basic proof-of-concept for doing a copy with linked SQEs. Needs a
* bit of error handling and short read love.
*/
#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/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include "../src/liburing.h"
#define QD 64
#define BS (32*1024)
struct io_data {
struct iovec iov;
};
static int infd, outfd;
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 int queue_rw_pair(struct io_uring *ring, off_t size, off_t offset)
{
struct io_uring_sqe *sqe;
struct io_data *data;
data = malloc(size + sizeof(*data));
data->iov.iov_base = data + 1;
data->iov.iov_len = size;
sqe = io_uring_get_sqe(ring);
io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
sqe->flags |= IOSQE_IO_LINK;
sqe = io_uring_get_sqe(ring);
io_uring_prep_writev(sqe, outfd, &data->iov, 1, offset);
io_uring_sqe_set_data(sqe, data);
return 0;
}
static void handle_cqe(struct io_uring_cqe *cqe)
{
struct io_data *data;
if (cqe->res < 0)
printf("cqe error: %s\n", strerror(cqe->res));
data = io_uring_cqe_get_data(cqe);
if (!data)
return;
free(data);
}
static int copy_file(struct io_uring *ring, off_t insize)
{
struct io_uring_cqe *cqe;
size_t this_size;
off_t offset;
int inflight;
offset = 0;
inflight = 0;
while (insize) {
int has_inflight = inflight;
while (inflight < QD) {
this_size = BS;
if (this_size > insize)
this_size = insize;
queue_rw_pair(ring, this_size, offset);
offset += this_size;
insize -= this_size;
inflight += 2;
}
if (has_inflight != inflight)
io_uring_submit(ring);
while (inflight >= QD) {
int ret;
ret = io_uring_wait_cqe(ring, &cqe);
assert(ret >= 0);
handle_cqe(cqe);
inflight--;
}
}
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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