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