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/* SPDX-License-Identifier: MIT */
/*
* Test 5.7 regression with task_work not being run while a task is
* waiting on another event in the kernel.
*/
#include <errno.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/eventfd.h>
#include <unistd.h>
#include <pthread.h>
#include "liburing.h"
#include "helpers.h"
static int use_sqpoll = 0;
void notify_fd(int fd)
{
char buf[8] = {0, 0, 0, 0, 0, 0, 1};
int ret;
ret = write(fd, &buf, 8);
if (ret < 0)
perror("write");
}
void *delay_set_fd_from_thread(void *data)
{
int fd = (intptr_t) data;
sleep(1);
notify_fd(fd);
return NULL;
}
int main(int argc, char *argv[])
{
struct io_uring_params p = {};
struct io_uring ring;
int loop_fd, other_fd;
struct io_uring_sqe *sqe;
struct io_uring_cqe *cqe = NULL;
int ret, use_fd;
char buf[8] = {0, 0, 0, 0, 0, 0, 1};
pthread_t tid;
if (argc > 1)
return 0;
/* Create an eventfd to be registered with the loop to be
* notified of events being ready
*/
loop_fd = eventfd(0, EFD_CLOEXEC);
if (loop_fd == -1) {
fprintf(stderr, "eventfd errno=%d\n", errno);
return 1;
}
/* Create an eventfd that can create events */
use_fd = other_fd = eventfd(0, EFD_CLOEXEC);
if (other_fd == -1) {
fprintf(stderr, "eventfd errno=%d\n", errno);
return 1;
}
if (use_sqpoll)
p.flags = IORING_SETUP_SQPOLL;
/* Setup the ring with a registered event fd to be notified on events */
ret = t_create_ring_params(8, &ring, &p);
if (ret == T_SETUP_SKIP)
return 0;
else if (ret < 0)
return ret;
ret = io_uring_register_eventfd(&ring, loop_fd);
if (ret < 0) {
fprintf(stderr, "register_eventfd=%d\n", ret);
return 1;
}
if (use_sqpoll) {
ret = io_uring_register_files(&ring, &other_fd, 1);
if (ret < 0) {
fprintf(stderr, "register_files=%d\n", ret);
return 1;
}
use_fd = 0;
}
/* Submit a poll operation to wait on an event in other_fd */
sqe = io_uring_get_sqe(&ring);
io_uring_prep_poll_add(sqe, use_fd, POLLIN);
sqe->user_data = 1;
if (use_sqpoll)
sqe->flags |= IOSQE_FIXED_FILE;
ret = io_uring_submit(&ring);
if (ret != 1) {
fprintf(stderr, "submit=%d\n", ret);
return 1;
}
/*
* CASE 3: Hangs forever in Linux 5.7.5; Works in Linux 5.6.0 When this
* code is uncommented, we don't se a notification on other_fd until
* _after_ we have started the read on loop_fd. In that case, the read() on
* loop_fd seems to hang forever.
*/
pthread_create(&tid, NULL, delay_set_fd_from_thread,
(void*) (intptr_t) other_fd);
/* Wait on the event fd for an event to be ready */
ret = read(loop_fd, buf, 8);
if (ret < 0) {
perror("read");
return 1;
} else if (ret != 8) {
fprintf(stderr, "Odd-sized eventfd read: %d\n", ret);
return 1;
}
ret = io_uring_wait_cqe(&ring, &cqe);
if (ret) {
fprintf(stderr, "wait_cqe=%d\n", ret);
return ret;
}
if (cqe->res < 0) {
fprintf(stderr, "cqe->res=%d\n", cqe->res);
return 1;
}
io_uring_cqe_seen(&ring, cqe);
return 0;
}
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