7f7a66e385
This is cleaner than having the app juggle an SQ and CQ ring, just wrap them in struct io_uring and have the API always take that. This means the app doesn't need to worry about the different types of rings, and that we only need to pass in one argument for setup/teardown. Signed-off-by: Jens Axboe <axboe@kernel.dk>
90 lines
1.8 KiB
C
90 lines
1.8 KiB
C
/*
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* Simple app that demonstrates how to setup an io_uring interface,
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* submit and complete IO against it, and then tear it down.
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*
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* gcc -Wall -O2 -D_GNU_SOURCE -o io_uring-test io_uring-test.c -luring
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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 "../src/liburing.h"
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int main(int argc, char *argv[])
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{
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struct io_uring_params p;
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struct io_uring ring;
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int i, fd, ring_fd, ret, pending, done;
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struct io_uring_iocb *iocb;
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struct io_uring_event *ev;
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off_t offset;
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void *buf;
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if (argc < 2) {
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printf("%s: file\n", argv[0]);
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return 1;
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}
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memset(&p, 0, sizeof(p));
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p.flags = IORING_SETUP_IOPOLL;
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ring_fd = io_uring_queue_init(4, &p, NULL, &ring);
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if (ring_fd < 0) {
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fprintf(stderr, "queue_init: %s\n", strerror(-ring_fd));
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return 1;
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}
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fd = open(argv[1], O_RDONLY | O_DIRECT);
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if (fd < 0) {
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perror("open");
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return 1;
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}
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if (posix_memalign(&buf, 4096, 4096))
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return 1;
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offset = 0;
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do {
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iocb = io_uring_get_iocb(&ring);
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if (!iocb)
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break;
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iocb->opcode = IORING_OP_READ;
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iocb->flags = 0;
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iocb->ioprio = 0;
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iocb->fd = fd;
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iocb->off = offset;
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iocb->addr = buf;
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iocb->len = 4096;
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offset += 4096;
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} while (1);
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ret = io_uring_submit(ring_fd, &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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return 1;
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}
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done = 0;
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pending = ret;
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for (i = 0; i < pending; i++) {
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ev = NULL;
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ret = io_uring_get_completion(ring_fd, &ring, &ev);
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if (ret < 0) {
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fprintf(stderr, "io_uring_get_completion: %s\n", strerror(-ret));
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return 1;
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}
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done++;
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if (ev->res != 4096) {
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fprintf(stderr, "ret=%d, wanted 4096\n", ev->res);
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return 1;
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}
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}
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printf("Submitted=%d, completed=%d\n", pending, done);
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close(fd);
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io_uring_queue_exit(ring_fd, &ring);
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return 0;
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}
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