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From: Marcelo Diop-Gonzalez <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], Marcelo Diop-Gonzalez <[email protected]>
Subject: [PATCH v2 0/2] io_uring: fix skipping of old timeout events
Date: Sat, 19 Dec 2020 14:15:19 -0500	[thread overview]
Message-ID: <[email protected]> (raw)

These two patches try to fix a problem with IORING_OP_TIMEOUT events
not being flushed if they should already have expired. The test below
hangs before this change (unless you run with $ ./a.out ~/somefile 1):

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <liburing.h>

int main(int argc, char **argv) {
	if (argc < 2)
		return 1;

	int fd = open(argv[1], O_RDONLY);
	if (fd < 0) {
		perror("open");
		return 1;
	}

	struct io_uring ring;
	io_uring_queue_init(4, &ring, 0);

	struct io_uring_sqe *sqe = io_uring_get_sqe(&ring);

	struct __kernel_timespec ts = { .tv_sec = 9999999 };
	io_uring_prep_timeout(sqe, &ts, 1, 0);
	sqe->user_data = 123;
	int ret = io_uring_submit(&ring);
	if (ret < 0) {
		fprintf(stderr, "submit(timeout_sqe): %d\n", ret);
		return 1;
	}

	int n = 2;
	if (argc > 2)
		n = atoi(argv[2]);

	char buf;
	for (int i = 0; i < n; i++) {
		sqe = io_uring_get_sqe(&ring);
		if (!sqe) {
			fprintf(stderr, "too many\n");
			exit(1);
		}
		io_uring_prep_read(sqe, fd, &buf, 1, 0);
	}
	ret = io_uring_submit(&ring);
	if (ret < 0) {
		fprintf(stderr, "submit(read_sqe): %d\n", ret);
		exit(1);
	}

	struct io_uring_cqe *cqe;
	for (int i = 0; i < n+1; i++) {
		struct io_uring_cqe *cqe;
		int ret = io_uring_wait_cqe(&ring, &cqe);
		if (ret < 0) {
			fprintf(stderr, "wait_cqe(): %d\n", ret);
			return 1;
		}
		if (cqe->user_data == 123)
			printf("timeout found\n");
		io_uring_cqe_seen(&ring, cqe);
	}
}

v2: Properly handle u32 overflow issues

Marcelo Diop-Gonzalez (2):
  io_uring: only increment ->cq_timeouts along with ->cached_cq_tail
  io_uring: flush timeouts that should already have expired

 fs/io_uring.c | 44 ++++++++++++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 14 deletions(-)

-- 
2.20.1


             reply	other threads:[~2020-12-19 19:16 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-19 19:15 Marcelo Diop-Gonzalez [this message]
2020-12-19 19:15 ` [PATCH v2 1/2] io_uring: only increment ->cq_timeouts along with ->cached_cq_tail Marcelo Diop-Gonzalez
2021-01-02 20:03   ` Pavel Begunkov
2021-01-04 16:49     ` Marcelo Diop-Gonzalez
2020-12-19 19:15 ` [PATCH v2 2/2] io_uring: flush timeouts that should already have expired Marcelo Diop-Gonzalez
2021-01-02 19:54   ` Pavel Begunkov
2021-01-02 20:26     ` Pavel Begunkov
2021-01-08 15:57       ` Marcelo Diop-Gonzalez
2021-01-11  4:57         ` Pavel Begunkov
2021-01-11 15:28           ` Marcelo Diop-Gonzalez
2021-01-12 20:47         ` Pavel Begunkov
2021-01-13 14:41           ` Marcelo Diop-Gonzalez
2021-01-13 15:20             ` Pavel Begunkov
2021-01-14  0:46           ` Marcelo Diop-Gonzalez
2021-01-14 21:04             ` Pavel Begunkov
2021-01-04 17:56     ` Marcelo Diop-Gonzalez

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