Re: [PATCH liburing v2 4/5] test: add io_uring passthrough test

[Kanchan Joshi <joshi.k@samsung.com>]

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On Tue, Jul 26, 2022 at 04:22:29PM +0530, Ankit Kumar wrote:
>Add a way to test uring passthrough commands, which was added
>with 5.19 kernel. This requires nvme-ns character device (/dev/ngXnY)
>as filename argument. It runs a combination of read/write tests with
>sqthread poll, vectored and non-vectored commands, fixed I/O buffers.
>
>Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>
>---
> test/Makefile               |   1 +
> test/io_uring_passthrough.c | 319 ++++++++++++++++++++++++++++++++++++
> 2 files changed, 320 insertions(+)
> create mode 100644 test/io_uring_passthrough.c
>
>diff --git a/test/Makefile b/test/Makefile
>index a36ddb3..418c11c 100644
>--- a/test/Makefile
>+++ b/test/Makefile
>@@ -90,6 +90,7 @@ test_srcs := \
> 	io-cancel.c \
> 	iopoll.c \
> 	io_uring_enter.c \
>+	io_uring_passthrough.c \
> 	io_uring_register.c \
> 	io_uring_setup.c \
> 	lfs-openat.c \
>diff --git a/test/io_uring_passthrough.c b/test/io_uring_passthrough.c
>new file mode 100644
>index 0000000..2e2b806
>--- /dev/null
>+++ b/test/io_uring_passthrough.c
>@@ -0,0 +1,319 @@
>+/* SPDX-License-Identifier: MIT */
>+/*
>+ * Description: basic read/write tests for io_uring passthrough commands
>+ */
>+#include <errno.h>
>+#include <stdio.h>
>+#include <unistd.h>
>+#include <stdlib.h>
>+#include <string.h>
>+
>+#include "helpers.h"
>+#include "liburing.h"
>+#include "nvme.h"
>+
>+#define FILE_SIZE	(256 * 1024)
>+#define BS		8192
>+#define BUFFERS		(FILE_SIZE / BS)
>+
>+static struct iovec *vecs;
>+
>+/*
>+ * Each offset in the file has the ((test_case / 2) * FILE_SIZE)
>+ * + (offset / sizeof(int)) stored for every
>+ * sizeof(int) address.
>+ */
>+static int verify_buf(int tc, void *buf, off_t off)
>+{
>+	int i, u_in_buf = BS / sizeof(unsigned int);
>+	unsigned int *ptr;
>+
>+	off /= sizeof(unsigned int);
>+	off += (tc / 2) * FILE_SIZE;
>+	ptr = buf;
>+	for (i = 0; i < u_in_buf; i++) {
>+		if (off != *ptr) {
>+			fprintf(stderr, "Found %u, wanted %lu\n", *ptr, off);
>+			return 1;
>+		}
>+		ptr++;
>+		off++;
>+	}
>+
>+	return 0;
>+}
>+
>+static int fill_pattern(int tc)
>+{
>+	unsigned int val, *ptr;
>+	int i, j;
>+	int u_in_buf = BS / sizeof(val);
>+
>+	val = (tc / 2) * FILE_SIZE;
>+	for (i = 0; i < BUFFERS; i++) {
>+		ptr = vecs[i].iov_base;
>+		for (j = 0; j < u_in_buf; j++) {
>+			*ptr = val;
>+			val++;
>+			ptr++;
>+		}
>+	}
>+
>+	return 0;
>+}
>+
>+static int __test_io(const char *file, struct io_uring *ring, int tc, int read,
>+		     int sqthread, int fixed, int nonvec)
>+{
>+	struct io_uring_sqe *sqe;
>+	struct io_uring_cqe *cqe;
>+	struct nvme_uring_cmd *cmd;
>+	int open_flags;
>+	int do_fixed;
>+	int i, ret, fd = -1;
>+	off_t offset;
>+	__u64 slba;
>+	__u32 nlb;
>+
>+#ifdef VERBOSE
>+	fprintf(stdout, "%s: start %d/%d/%d/%d: ", __FUNCTION__, read,
>+							sqthread, fixed,
>+							nonvec);
>+#endif
>+	if (read)
>+		open_flags = O_RDONLY;
>+	else
>+		open_flags = O_WRONLY;
>+
>+	if (fixed) {
>+		ret = t_register_buffers(ring, vecs, BUFFERS);
>+		if (ret == T_SETUP_SKIP)
>+			return 0;
>+		if (ret != T_SETUP_OK) {
>+			fprintf(stderr, "buffer reg failed: %d\n", ret);
>+			goto err;
>+		}
>+	}
>+
>+	fd = open(file, open_flags);
>+	if (fd < 0) {
>+		perror("file open");
>+		goto err;
>+	}
>+
>+	if (sqthread) {
>+		ret = io_uring_register_files(ring, &fd, 1);
>+		if (ret) {
>+			fprintf(stderr, "file reg failed: %d\n", ret);
>+			goto err;
>+		}
>+	}
>+
>+	if (!read)
>+		fill_pattern(tc);
>+
>+	offset = 0;
>+	for (i = 0; i < BUFFERS; i++) {
>+		sqe = io_uring_get_sqe(ring);
>+		if (!sqe) {
>+			fprintf(stderr, "sqe get failed\n");
>+			goto err;
>+		}
>+		if (read) {
>+			int use_fd = fd;
>+
>+			do_fixed = fixed;
>+
>+			if (sqthread)
>+				use_fd = 0;
>+			if (fixed && (i & 1))
>+				do_fixed = 0;
>+			if (do_fixed) {
>+				io_uring_prep_read_fixed(sqe, use_fd, vecs[i].iov_base,
>+								vecs[i].iov_len,
>+								offset, i);
>+				sqe->cmd_op = NVME_URING_CMD_IO;
>+			} else if (nonvec) {
>+				io_uring_prep_read(sqe, use_fd, vecs[i].iov_base,
>+							vecs[i].iov_len, offset);
>+				sqe->cmd_op = NVME_URING_CMD_IO;
>+			} else {
>+				io_uring_prep_readv(sqe, use_fd, &vecs[i], 1,
>+								offset);
>+				sqe->cmd_op = NVME_URING_CMD_IO_VEC;
>+			}
>+		} else {
>+			int use_fd = fd;
>+
>+			do_fixed = fixed;
>+
>+			if (sqthread)
>+				use_fd = 0;
>+			if (fixed && (i & 1))
>+				do_fixed = 0;
>+			if (do_fixed) {
>+				io_uring_prep_write_fixed(sqe, use_fd, vecs[i].iov_base,
>+								vecs[i].iov_len,
>+								offset, i);
>+				sqe->cmd_op = NVME_URING_CMD_IO;
>+			} else if (nonvec) {
>+				io_uring_prep_write(sqe, use_fd, vecs[i].iov_base,
>+							vecs[i].iov_len, offset);
>+				sqe->cmd_op = NVME_URING_CMD_IO;
>+			} else {
>+				io_uring_prep_writev(sqe, use_fd, &vecs[i], 1,
>+								offset);
>+				sqe->cmd_op = NVME_URING_CMD_IO_VEC;
>+			}
>+		}
>+		sqe->opcode = IORING_OP_URING_CMD;
>+		sqe->user_data = ((uint64_t)offset << 32) | i;
>+		if (sqthread)
>+			sqe->flags |= IOSQE_FIXED_FILE;
>+
>+		/* 80 bytes for NVMe uring passthrough command */
>+		cmd = (struct nvme_uring_cmd *)sqe->cmd;
>+		memset(cmd, 0, sizeof(struct nvme_uring_cmd));

The above 80 bytes commment does not serve much purpose since
you are using sizeof(struct nvme_uring_cmd) anyway and do not use the
magic number. Moreover actual size is 72 bytes. But this is a nit and
things look fine to me, so -

Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>

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