[LTP] [PATCH 2/3] io_uring: Test READV and WRITEV operations

[Sachin Sant <sachinp@linux.ibm.com>]

This test validates vectored read and write operations using io_uring.

1. IORING_OP_WRITEV - Writing data using multiple buffers (scatter)
2. IORING_OP_READV - Reading data into multiple buffers (gather)
3. Data integrity verification across multiple iovecs
4. Edge cases with different iovec configurations

Signed-off-by: Sachin Sant <sachinp@linux.ibm.com>
---
 runtest/syscalls                              |   1 +
 testcases/kernel/syscalls/io_uring/.gitignore |   1 +
 .../kernel/syscalls/io_uring/io_uring04.c     | 231 ++++++++++++++++++
 3 files changed, 233 insertions(+)
 create mode 100644 testcases/kernel/syscalls/io_uring/io_uring04.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 7dc80fe29..eacf946c5 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1899,6 +1899,7 @@ membarrier01 membarrier01
 io_uring01 io_uring01
 io_uring02 io_uring02
 io_uring03 io_uring03
+io_uring04 io_uring04
 
 # Tests below may cause kernel memory leak
 perf_event_open03 perf_event_open03
diff --git a/testcases/kernel/syscalls/io_uring/.gitignore b/testcases/kernel/syscalls/io_uring/.gitignore
index 9382ae413..36cd24662 100644
--- a/testcases/kernel/syscalls/io_uring/.gitignore
+++ b/testcases/kernel/syscalls/io_uring/.gitignore
@@ -1,3 +1,4 @@
 /io_uring01
 /io_uring02
 /io_uring03
+/io_uring04
diff --git a/testcases/kernel/syscalls/io_uring/io_uring04.c b/testcases/kernel/syscalls/io_uring/io_uring04.c
new file mode 100644
index 000000000..27d1c509b
--- /dev/null
+++ b/testcases/kernel/syscalls/io_uring/io_uring04.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 IBM
+ * Author: Sachin Sant <sachinp@linux.ibm.com>
+ */
+/*
+ * Test IORING_OP_READV and IORING_OP_WRITEV operations.
+ *
+ * This test validates vectored read and write operations using io_uring.
+ * It tests:
+ * 1. IORING_OP_WRITEV - Writing data using multiple buffers (scatter)
+ * 2. IORING_OP_READV - Reading data into multiple buffers (gather)
+ * 3. Data integrity verification across multiple iovecs
+ * 4. Edge cases with different iovec configurations
+ */
+
+#include "io_uring_common.h"
+
+#define TEST_FILE "io_uring_test_file"
+#define QUEUE_DEPTH 2
+#define NUM_VECS 4
+#define VEC_SIZE 1024
+
+static char write_bufs[NUM_VECS][VEC_SIZE];
+static char read_bufs[NUM_VECS][VEC_SIZE];
+static struct iovec write_iovs[NUM_VECS];
+static struct iovec read_iovs[NUM_VECS];
+static struct io_uring_submit s;
+static sigset_t sig;
+
+static void prepare_write_buffers(void)
+{
+	size_t i, j;
+
+	for (i = 0; i < NUM_VECS; i++) {
+		for (j = 0; j < VEC_SIZE; j++) {
+			/* Each vector has a different pattern */
+			write_bufs[i][j] = 'A' + i + (j % 26);
+		}
+		write_iovs[i].iov_base = write_bufs[i];
+		write_iovs[i].iov_len = VEC_SIZE;
+	}
+}
+
+static void prepare_read_buffers(void)
+{
+	size_t i;
+
+	for (i = 0; i < NUM_VECS; i++) {
+		memset(read_bufs[i], 0, VEC_SIZE);
+		read_iovs[i].iov_base = read_bufs[i];
+		read_iovs[i].iov_len = VEC_SIZE;
+	}
+}
+
+static void verify_vector_data(char write_bufs[][VEC_SIZE],
+			       char read_bufs[][VEC_SIZE],
+			       size_t num_vecs, const char *test_name)
+{
+	size_t i, j;
+
+	for (i = 0; i < num_vecs; i++) {
+		if (memcmp(write_bufs[i], read_bufs[i], VEC_SIZE) != 0) {
+			tst_res(TFAIL, "%s: data mismatch in vector %zu",
+				test_name, i);
+			for (j = 0; j < VEC_SIZE && j < 64; j++) {
+				if (write_bufs[i][j] != read_bufs[i][j]) {
+					tst_res(TINFO, "Vector %zu: first mismatch at "
+						"offset %zu: wrote 0x%02x, read 0x%02x",
+						i, j, write_bufs[i][j], read_bufs[i][j]);
+					break;
+				}
+			}
+			return;
+		}
+	}
+
+	tst_res(TPASS, "%s: data integrity verified across %zu vectors",
+		test_name, num_vecs);
+}
+
+static void test_writev_readv(void)
+{
+	int fd;
+	int total_size = NUM_VECS * VEC_SIZE;
+
+	tst_res(TINFO, "Testing IORING_OP_WRITEV and IORING_OP_READV");
+
+	prepare_write_buffers();
+	prepare_read_buffers();
+
+	fd = SAFE_OPEN(TEST_FILE, O_RDWR | O_CREAT | O_TRUNC, 0644);
+
+	tst_res(TINFO, "Writing %d bytes using %d vectors", total_size, NUM_VECS);
+	io_uring_do_vec_io_op(&s, fd, IORING_OP_WRITEV, write_iovs, NUM_VECS,
+			      0, total_size, &sig,
+			      "IORING_OP_WRITEV completed successfully");
+
+	SAFE_FSYNC(fd);
+
+	tst_res(TINFO, "Reading %d bytes using %d vectors", total_size, NUM_VECS);
+	io_uring_do_vec_io_op(&s, fd, IORING_OP_READV, read_iovs, NUM_VECS,
+			      0, total_size, &sig,
+			      "IORING_OP_READV completed successfully");
+
+	verify_vector_data(write_bufs, read_bufs, NUM_VECS, "Basic vectored I/O");
+
+	SAFE_CLOSE(fd);
+}
+
+static void test_partial_vectors(void)
+{
+	int fd;
+	struct iovec partial_write[2];
+	struct iovec partial_read[2];
+	int expected_size;
+
+	tst_res(TINFO, "Testing partial vector operations");
+
+	prepare_write_buffers();
+	prepare_read_buffers();
+
+	fd = SAFE_OPEN(TEST_FILE, O_RDWR | O_CREAT | O_TRUNC, 0644);
+
+	/* Write using only 2 vectors */
+	partial_write[0] = write_iovs[0];
+	partial_write[1] = write_iovs[1];
+	expected_size = 2 * VEC_SIZE;
+
+	io_uring_do_vec_io_op(&s, fd, IORING_OP_WRITEV, partial_write, 2, 0,
+			      expected_size, &sig,
+			      "Partial IORING_OP_WRITEV (2 vectors) succeeded");
+
+	SAFE_FSYNC(fd);
+
+	/* Read back using 2 vectors */
+	partial_read[0] = read_iovs[0];
+	partial_read[1] = read_iovs[1];
+
+	io_uring_do_vec_io_op(&s, fd, IORING_OP_READV, partial_read, 2, 0,
+			      expected_size, &sig,
+			      "Partial IORING_OP_READV (2 vectors) succeeded");
+
+	verify_vector_data(write_bufs, read_bufs, 2, "Partial vector I/O");
+
+	SAFE_CLOSE(fd);
+}
+
+static void test_varying_sizes(void)
+{
+	int fd;
+	struct iovec var_write[3];
+	struct iovec var_read[3];
+	char buf1[512], buf2[1024], buf3[256];
+	char rbuf1[512], rbuf2[1024], rbuf3[256];
+	int expected_size = 512 + 1024 + 256;
+
+	tst_res(TINFO, "Testing vectors with varying sizes");
+
+	io_uring_init_buffer_pattern(buf1, 512, 'X');
+	io_uring_init_buffer_pattern(buf2, 1024, 'Y');
+	io_uring_init_buffer_pattern(buf3, 256, 'Z');
+
+	var_write[0].iov_base = buf1;
+	var_write[0].iov_len = 512;
+	var_write[1].iov_base = buf2;
+	var_write[1].iov_len = 1024;
+	var_write[2].iov_base = buf3;
+	var_write[2].iov_len = 256;
+
+	memset(rbuf1, 0, 512);
+	memset(rbuf2, 0, 1024);
+	memset(rbuf3, 0, 256);
+
+	var_read[0].iov_base = rbuf1;
+	var_read[0].iov_len = 512;
+	var_read[1].iov_base = rbuf2;
+	var_read[1].iov_len = 1024;
+	var_read[2].iov_base = rbuf3;
+	var_read[2].iov_len = 256;
+
+	fd = SAFE_OPEN(TEST_FILE, O_RDWR | O_CREAT | O_TRUNC, 0644);
+
+	io_uring_do_vec_io_op(&s, fd, IORING_OP_WRITEV, var_write, 3, 0,
+			      expected_size, &sig,
+			      "IORING_OP_WRITEV with varying sizes succeeded");
+
+	SAFE_FSYNC(fd);
+
+	io_uring_do_vec_io_op(&s, fd, IORING_OP_READV, var_read, 3, 0,
+			      expected_size, &sig,
+			      "IORING_OP_READV with varying sizes succeeded");
+
+	/* Verify each buffer */
+	if (memcmp(buf1, rbuf1, 512) == 0 &&
+	    memcmp(buf2, rbuf2, 1024) == 0 &&
+	    memcmp(buf3, rbuf3, 256) == 0) {
+		tst_res(TPASS, "Varying size vector data integrity verified");
+	} else {
+		tst_res(TFAIL, "Varying size vector data mismatch");
+	}
+
+	SAFE_CLOSE(fd);
+}
+
+static void run(void)
+{
+	io_uring_setup_queue(&s, QUEUE_DEPTH);
+	test_writev_readv();
+	test_partial_vectors();
+	test_varying_sizes();
+	io_uring_cleanup_queue(&s, QUEUE_DEPTH);
+}
+
+static void setup(void)
+{
+	io_uring_setup_supported_by_kernel();
+	sigemptyset(&sig);
+	memset(&s, 0, sizeof(s));
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.setup = setup,
+	.needs_tmpdir = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{"/proc/sys/kernel/io_uring_disabled", "0",
+			TST_SR_SKIP_MISSING | TST_SR_TCONF_RO},
+		{}
+	}
+};
-- 
2.39.1


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