[LTP] [RFC] [PATCH 2/2] io_uring: Test READV and WRITEV operations
Sachin Sant
sachinp@linux.ibm.com
Wed Mar 18 12:03:28 CET 2026
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
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 | 248 ++++++++++++++++++
3 files changed, 250 insertions(+)
create mode 100644 testcases/kernel/syscalls/io_uring/io_uring04.c
diff --git a/runtest/syscalls b/runtest/syscalls
index 7dc80fe29..100ae7706 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_uring03 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..fa61f0962
--- /dev/null
+++ b/testcases/kernel/syscalls/io_uring/io_uring04.c
@@ -0,0 +1,248 @@
+// 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 test_writev_readv(void)
+{
+ int fd;
+ size_t i, j;
+ 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);
+
+ /* Test IORING_OP_WRITEV */
+ tst_res(TINFO, "Writing %d bytes using %d vectors", total_size, NUM_VECS);
+ io_uring_submit_sqe_vec(&s, fd, IORING_OP_WRITEV, write_iovs,
+ NUM_VECS, 0);
+
+ if (io_uring_wait_cqe(&s, total_size, IORING_OP_WRITEV, &sig) == 0)
+ tst_res(TPASS, "IORING_OP_WRITEV completed successfully");
+
+ SAFE_FSYNC(fd);
+
+ /* Test IORING_OP_READV */
+ tst_res(TINFO, "Reading %d bytes using %d vectors", total_size, NUM_VECS);
+ io_uring_submit_sqe_vec(&s, fd, IORING_OP_READV, read_iovs,
+ NUM_VECS, 0);
+
+ if (io_uring_wait_cqe(&s, total_size, IORING_OP_READV, &sig) == 0)
+ tst_res(TPASS, "IORING_OP_READV completed successfully");
+
+ /* Verify data integrity for each vector */
+ for (i = 0; i < NUM_VECS; i++) {
+ if (memcmp(write_bufs[i], read_bufs[i], VEC_SIZE) != 0) {
+ tst_res(TFAIL, "Data mismatch in vector %zu", 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;
+ }
+ }
+ SAFE_CLOSE(fd);
+ return;
+ }
+ }
+
+ tst_res(TPASS, "Data integrity verified across all %d vectors", NUM_VECS);
+ SAFE_CLOSE(fd);
+}
+
+static void test_partial_vectors(void)
+{
+ int fd;
+ struct iovec partial_write[2];
+ struct iovec partial_read[2];
+ size_t i;
+ 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_submit_sqe_vec(&s, fd, IORING_OP_WRITEV, partial_write, 2, 0);
+ if (io_uring_wait_cqe(&s, expected_size, IORING_OP_WRITEV, &sig) == 0)
+ tst_res(TPASS, "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_submit_sqe_vec(&s, fd, IORING_OP_READV, partial_read, 2, 0);
+ if (io_uring_wait_cqe(&s, expected_size, IORING_OP_READV, &sig) == 0)
+ tst_res(TPASS, "Partial IORING_OP_READV (2 vectors) succeeded");
+
+ /* Verify only the first 2 vectors */
+ for (i = 0; i < 2; i++) {
+ if (memcmp(write_bufs[i], read_bufs[i], VEC_SIZE) != 0) {
+ tst_res(TFAIL, "Partial vector data mismatch at vector %zu", i);
+ SAFE_CLOSE(fd);
+ return;
+ }
+ }
+
+ tst_res(TPASS, "Partial vector data integrity verified");
+ 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];
+ size_t i;
+ int expected_size = 512 + 1024 + 256;
+
+ tst_res(TINFO, "Testing vectors with varying sizes");
+
+ /* Prepare buffers with different sizes */
+ for (i = 0; i < 512; i++)
+ buf1[i] = 'X';
+ for (i = 0; i < 1024; i++)
+ buf2[i] = 'Y';
+ for (i = 0; i < 256; i++)
+ buf3[i] = '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);
+
+ /* Write with varying sizes */
+ io_uring_submit_sqe_vec(&s, fd, IORING_OP_WRITEV, var_write, 3, 0);
+ if (io_uring_wait_cqe(&s, expected_size, IORING_OP_WRITEV, &sig) == 0)
+ tst_res(TPASS, "IORING_OP_WRITEV with varying sizes succeeded");
+
+ SAFE_FSYNC(fd);
+
+ /* Read back with varying sizes */
+ io_uring_submit_sqe_vec(&s, fd, IORING_OP_READV, var_read, 3, 0);
+ if (io_uring_wait_cqe(&s, expected_size, IORING_OP_READV, &sig) == 0)
+ tst_res(TPASS, "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},
+ {}
+ },
+ .tags = (const struct tst_tag[]) {
+ {"linux-git", "2b188cc1bb85"},
+ {"linux-git", "f67676d160c6"},
+ {}
+ }
+};
--
2.39.1
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