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* [PATCH v3 0/1] io_uring: fix skipping of old timeout events
@ 2021-01-14 15:50 Marcelo Diop-Gonzalez
  2021-01-14 15:50 ` [PATCH v3 1/1] io_uring: flush timeouts that should already have expired Marcelo Diop-Gonzalez
  2021-01-14 21:42 ` [PATCH v3 0/1] io_uring: fix skipping of old timeout events Pavel Begunkov
  0 siblings, 2 replies; 6+ messages in thread
From: Marcelo Diop-Gonzalez @ 2021-01-14 15:50 UTC (permalink / raw)
  To: axboe, asml.silence; +Cc: io-uring, Marcelo Diop-Gonzalez

This patch tries 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);
	}
}

v3: Add ->last_flush member to handle more overflow issues
v2: Properly handle u32 overflow issues

Marcelo Diop-Gonzalez (1):
  io_uring: flush timeouts that should already have expired

 fs/io_uring.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

-- 
2.20.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-01-15 16:38 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-01-14 15:50 [PATCH v3 0/1] io_uring: fix skipping of old timeout events Marcelo Diop-Gonzalez
2021-01-14 15:50 ` [PATCH v3 1/1] io_uring: flush timeouts that should already have expired Marcelo Diop-Gonzalez
2021-01-14 21:40   ` Pavel Begunkov
2021-01-15 14:45     ` Pavel Begunkov
2021-01-14 21:42 ` [PATCH v3 0/1] io_uring: fix skipping of old timeout events Pavel Begunkov
2021-01-15 16:37   ` Marcelo Diop-Gonzalez

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