linux-kernel - [liburing PATCH] flush/test: test flush of dying process

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Date:   Sun,  7 Jun 2020 18:32:21 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Jens Axboe <axboe@...nel.dk>, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [liburing PATCH] flush/test: test flush of dying process

Make sure all requests of a going away process are cancelled.

Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 test/io-cancel.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)

diff --git a/test/io-cancel.c b/test/io-cancel.c
index 75fbf43..d8b04d9 100644
--- a/test/io-cancel.c
+++ b/test/io-cancel.c
@@ -10,6 +10,8 @@
 #include <fcntl.h>
 #include <sys/types.h>
 #include <sys/time.h>
+#include <sys/mman.h>
+#include <sys/wait.h>
 
 #include "liburing.h"
 
@@ -17,6 +19,8 @@
 #define BS		4096
 #define BUFFERS		(FILE_SIZE / BS)
 
+#define NR_REQS 10
+
 static struct iovec *vecs;
 
 static int create_buffers(void)
@@ -228,10 +232,108 @@ err:
 	return 1;
 }
 
+static void submit_child(struct io_uring *ring, int fds[2])
+{
+	struct io_uring_sqe *sqe;
+	int ret, i;
+	char buffer[128];
+
+	for (i = 0; i < NR_REQS; ++i) {
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			fprintf(stderr, "get sqe failed\n");
+			goto err;
+		}
+		io_uring_prep_read(sqe, fds[0], buffer, sizeof(buffer), 0);
+		sqe->flags |= IOSQE_ASYNC;
+	}
+
+	ret = io_uring_submit(ring);
+	if (ret != NR_REQS) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	exit(0);
+err:
+	exit(-1);
+}
+
+/* make sure requests of a going away task are cancelled */
+static int test_cancel_exiting_task(void)
+{
+	struct io_uring *ring;
+	int ret, i;
+	pid_t p;
+	int fds[2];
+
+	ring = mmap(0, sizeof(*ring), PROT_READ|PROT_WRITE,
+		    MAP_SHARED | MAP_ANONYMOUS, 0, 0);
+	if (!ring) {
+		fprintf(stderr, "mmap failed\n");
+		return 1;
+	}
+
+	ret = io_uring_queue_init(NR_REQS * 2, ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "queue init failed\n");
+		return 1;
+	}
+
+	if (pipe(fds)) {
+		perror("pipe() failed");
+		exit(1);
+	}
+
+	p = fork();
+	if (p < 0) {
+		printf("fork() failed\n");
+		return 1;
+	}
+
+	if (p == 0) {
+		/* child */
+		submit_child(ring, fds);
+	} else {
+		int wstatus;
+		struct io_uring_cqe *cqe;
+
+		waitpid(p, &wstatus, 0);
+		if (!WIFEXITED(wstatus) || WEXITSTATUS(wstatus) != 0) {
+			fprintf(stderr, "child failed\n");
+			return 1;
+		}
+
+		for (i = 0; i < NR_REQS; ++i) {
+			ret = io_uring_wait_cqe(ring, &cqe);
+			if (ret < 0) {
+				printf("wait_cqes: wait completion %d\n", ret);
+				return 1;
+			}
+			if (cqe->res != -ECANCELED && cqe->res != -EINTR) {
+				fprintf(stderr, "invalid CQE: %i\n", cqe->res);
+				return 1;
+			}
+			io_uring_cqe_seen(ring, cqe);
+		}
+	}
+
+	close(fds[0]);
+	close(fds[1]);
+	io_uring_queue_exit(ring);
+	munmap(ring, sizeof(*ring));
+	return 0;
+}
+
 int main(int argc, char *argv[])
 {
 	int i, ret;
 
+	if (test_cancel_exiting_task()) {
+		fprintf(stderr, "test_cancel_exiting_task failed\n");
+		return 1;
+	}
+
 	if (create_file(".basic-rw")) {
 		fprintf(stderr, "file creation failed\n");
 		goto err;
-- 
2.24.0