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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/types.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;
- data = malloc(size + sizeof(*data));
- if (!data)
- return 1;
- sqe = io_uring_get_sqe(ring);
- if (!sqe) {
- free(data);
- return 1;
- }
- 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_cqe(ring, &cqe);
- got_comp = 1;
- } else
- ret = io_uring_peek_cqe(ring, &cqe);
- if (ret < 0) {
- fprintf(stderr, "io_uring_peek_cqe: %s\n",
- strerror(-ret));
- return 1;
- }
- if (!cqe)
- break;
- data = io_uring_cqe_get_data(cqe);
- if (cqe->res < 0) {
- if (cqe->res == -EAGAIN) {
- queue_prepped(ring, data);
- io_uring_cqe_seen(ring, cqe);
- 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);
- io_uring_cqe_seen(ring, cqe);
- 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--;
- }
- io_uring_cqe_seen(ring, cqe);
- }
- }
- 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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