[PATCH liburing 1/1] tests: test shmem buffer registration

[Pavel Begunkov <asml.silence@gmail.com>]

Add a simple test registering a chunk of memfd (shmem) memory and doing
some I/O with it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 test/io_uring_register.c | 113 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)

diff --git a/test/io_uring_register.c b/test/io_uring_register.c
index 1d0981b..53e3987 100644
--- a/test/io_uring_register.c
+++ b/test/io_uring_register.c
@@ -485,6 +485,113 @@ test_poll_ringfd(void)
 	return status;
 }
 
+static int test_shmem(void)
+{
+	const char pattern = 0xEA;
+	const int len = 4096;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring ring;
+	struct iovec iov;
+	int memfd, ret, i;
+	char *mem;
+	int pipefd[2] = {-1, -1};
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret)
+		return 1;
+
+	if (pipe(pipefd)) {
+		perror("pipe");
+		return 1;
+	}
+	memfd = memfd_create("uring-shmem-test", 0);
+	if (memfd < 0) {
+		fprintf(stderr, "memfd_create() failed %i\n", -errno);
+		return 1;
+	}
+	if (ftruncate(memfd, len)) {
+		fprintf(stderr, "can't truncate memfd\n");
+		return 1;
+	}
+	mem = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, memfd, 0);
+	if (!mem) {
+		fprintf(stderr, "mmap failed\n");
+		return 1;
+	}
+	for (i = 0; i < len; i++)
+		mem[i] = pattern;
+
+	iov.iov_base = mem;
+	iov.iov_len = len;
+	ret = io_uring_register_buffers(&ring, &iov, 1);
+	if (ret) {
+		if (ret == -EOPNOTSUPP) {
+			fprintf(stdout, "memfd registration isn't supported, "
+					"skip\n");
+			goto out;
+		}
+
+		fprintf(stderr, "buffer reg failed: %d\n", ret);
+		return 1;
+	}
+
+	/* check that we can read and write from/to shmem reg buffer */
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_write_fixed(sqe, pipefd[1], mem, 512, 0, 0);
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit write failed\n");
+		return 1;
+	}
+	ret = io_uring_wait_cqe(&ring, &cqe);
+	if (ret < 0 || cqe->user_data != 1 || cqe->res != 512) {
+		fprintf(stderr, "reading from shmem failed\n");
+		return 1;
+	}
+	io_uring_cqe_seen(&ring, cqe);
+
+	/* clean it, should be populated with the pattern back from the pipe */
+	memset(mem, 0, 512);
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_read_fixed(sqe, pipefd[0], mem, 512, 0, 0);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit write failed\n");
+		return 1;
+	}
+	ret = io_uring_wait_cqe(&ring, &cqe);
+	if (ret < 0 || cqe->user_data != 2 || cqe->res != 512) {
+		fprintf(stderr, "reading from shmem failed\n");
+		return 1;
+	}
+	io_uring_cqe_seen(&ring, cqe);
+
+	for (i = 0; i < 512; i++) {
+		if (mem[i] != pattern) {
+			fprintf(stderr, "data integrity fail\n");
+			return 1;
+		}
+	}
+
+	ret = io_uring_unregister_buffers(&ring);
+	if (ret) {
+		fprintf(stderr, "buffer unreg failed: %d\n", ret);
+		return 1;
+	}
+out:
+	io_uring_queue_exit(&ring);
+	close(pipefd[0]);
+	close(pipefd[1]);
+	munmap(mem, len);
+	close(memfd);
+	return 0;
+}
+
 int
 main(int argc, char **argv)
 {
@@ -541,5 +648,11 @@ main(int argc, char **argv)
 	else
 		printf("FAIL\n");
 
+	ret = test_shmem();
+	if (ret) {
+		fprintf(stderr, "test_shmem() failed\n");
+		status |= 1;
+	}
+
 	return status;
 }
-- 
2.31.1