Re: [LTP] [PATCH v4] io_submit04: Add test case for RWF_NOWAIT flag

Andrea Cervesato via ltp
2026-02-18T12:22:13Z

Hi!

On Wed Jan 7, 2026 at 7:10 AM CET, Wei Gao wrote:
> Fixes: #467
> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
> configure.ac | 1 +
> include/lapi/aio_abi.h | 44 +++++++++
> runtest/syscalls | 1 +
> .../kernel/syscalls/io_submit/.gitignore | 1 +
> .../kernel/syscalls/io_submit/io_submit04.c | 94 +++++++++++++++++++
> 5 files changed, 141 insertions(+)
> create mode 100644 include/lapi/aio_abi.h
> create mode 100644 testcases/kernel/syscalls/io_submit/io_submit04.c
>
> diff --git a/configure.ac b/configure.ac
> index a0ebbb34d..ee46e3f24 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -172,6 +172,7 @@ AC_CHECK_FUNCS_ONCE([ \
> ])
> AC_CHECK_FUNCS(mkdtemp,[],AC_MSG_ERROR(mkdtemp() not found!))
>
> +AC_CHECK_MEMBERS([struct iocb.aio_rw_flags],,,[#include <linux/aio_abi.h>])
> AC_CHECK_MEMBERS([struct fanotify_event_info_fid.fsid.__val],,,[#include <sys/fanotify.h>])
> AC_CHECK_MEMBERS([struct perf_event_mmap_page.aux_head],,,[#include <linux/perf_event.h>])
> AC_CHECK_MEMBERS([struct sigaction.sa_sigaction],[],[],[#include <signal.h>])
> diff --git a/include/lapi/aio_abi.h b/include/lapi/aio_abi.h
> new file mode 100644
> index 000000000..bd8c2965b
> --- /dev/null
> +++ b/include/lapi/aio_abi.h
> @@ -0,0 +1,44 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2025 Wei Gao <wegao@suse.com>
> + */
> +
> +#ifndef LAPI_AIO_ABI_H__
> +#define LAPI_AIO_ABI_H__
> +
> +#include <endian.h>
> +#include <linux/aio_abi.h>
> +
> +#ifndef RWF_NOWAIT
> +# define RWF_NOWAIT 0x00000008
> +#endif
> +
> +struct iocb_fallback {
> + uint64_t aio_data;
> +#if __BYTE_ORDER == __LITTLE_ENDIAN
> + uint32_t aio_key;
> + uint32_t aio_rw_flags;
> +#elif __BYTE_ORDER == __BIG_ENDIAN
> + uint32_t aio_rw_flags;
> + uint32_t aio_key;
> +#else
> +#error edit for your odd byteorder.
> +#endif
> + uint16_t aio_lio_opcode;
> + int16_t aio_reqprio;
> + uint32_t aio_fildes;
> + uint64_t aio_buf;
> + uint64_t aio_nbytes;
> + int64_t aio_offset;
> + uint64_t aio_reserved2;
> + uint32_t aio_flags;
> + uint32_t aio_resfd;
> +};

checkpatch.pl reports you are using too many spaces for indentation in here.

> +
> +#ifndef HAVE_STRUCT_IOCB_AIO_RW_FLAGS
> +typedef struct iocb_fallback iocb;

Why not just define here the iocb, instead of having iocb_fallback
defined before?

> +#else
> +typedef struct iocb iocb;

And this would not be needed then.

> +#endif
> +
> +#endif /* LAPI_AIO_ABI_H__ */
> diff --git a/runtest/syscalls b/runtest/syscalls
> index a1ef7548b..18182a2d6 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -696,6 +696,7 @@ io_setup02 io_setup02
> io_submit01 io_submit01
> io_submit02 io_submit02
> io_submit03 io_submit03
> +io_submit04 io_submit04
>
> keyctl01 keyctl01
> keyctl02 keyctl02
> diff --git a/testcases/kernel/syscalls/io_submit/.gitignore b/testcases/kernel/syscalls/io_submit/.gitignore
> index 60b07970a..abe962e1c 100644
> --- a/testcases/kernel/syscalls/io_submit/.gitignore
> +++ b/testcases/kernel/syscalls/io_submit/.gitignore
> @@ -1,3 +1,4 @@
> /io_submit01
> /io_submit02
> /io_submit03
> +/io_submit04
> diff --git a/testcases/kernel/syscalls/io_submit/io_submit04.c b/testcases/kernel/syscalls/io_submit/io_submit04.c
> new file mode 100644
> index 000000000..d085d3238
> --- /dev/null
> +++ b/testcases/kernel/syscalls/io_submit/io_submit04.c
> @@ -0,0 +1,94 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2025 Wei Gao <wegao@suse.com>
> + */
> +
> +/*\
> + * Test RWF_NOWAIT support in io_submit(), verifying that an
> + * asynchronous read operation on a blocking resource (empty pipe)
> + * will cause -EAGAIN. This is done by checking that io_getevents()
> + * syscall returns immediately and io_event.res is equal to -EAGAIN.
> + */
> +
> +#include "config.h"
> +#include "tst_test.h"
> +#include "lapi/syscalls.h"
> +#include "lapi/aio_abi.h"
> +
> +

nit: double blank-line is not needed.

> +#define BUF_SIZE 100
> +
> +static int fd[2];

fd should be initialized to -1 and compared to this value in the
cleanup() before closing. zero is a valid value for file descriptors
(stdin).

> +
> +static aio_context_t ctx;
> +static char *buf;
> +static iocb *cb;
> +static iocb **iocbs;
> +
> +static void setup(void)
> +{
> + TST_EXP_PASS_SILENT(tst_syscall(__NR_io_setup, 1, &ctx));

We need to break the test here if io_setup fails. Silently failing it
will keep test running.

> + SAFE_PIPE(fd);
> +
> + cb->aio_fildes = fd[0];
> + cb->aio_lio_opcode = IOCB_CMD_PREAD;
> + cb->aio_buf = (uint64_t)buf;
> + cb->aio_offset = 0;
> + cb->aio_nbytes = BUF_SIZE;
> + cb->aio_rw_flags = RWF_NOWAIT;
> +
> + iocbs[0] = cb;
> +}
> +
> +static void cleanup(void)
> +{
> + if (fd[0])
> + SAFE_CLOSE(fd[0]);
> +
> + if (fd[1])
> + SAFE_CLOSE(fd[1]);
> +
> + if (ctx)
> + if (tst_syscall(__NR_io_destroy, ctx))
> + tst_brk(TBROK | TERRNO, "io_destroy() failed");
> +}
> +
> +static void run(void)
> +{
> + struct io_event evbuf;
> + struct timespec timeout = { .tv_sec = 1 };
> + long nr = 1;
> +
> + TEST(tst_syscall(__NR_io_submit, ctx, nr, iocbs));
> +
> + if (TST_RET == -1 && errno == EOPNOTSUPP) {
> + tst_brk(TCONF, "RWF_NOWAIT not supported by kernel");
> + } else if (TST_RET != nr) {
> + tst_brk(TBROK | TTERRNO, "io_submit() returns %ld, expected %ld",
> + TST_RET, nr);
> + }
> +
> + tst_syscall(__NR_io_getevents, ctx, 1, 1, &evbuf, &timeout);

Return value is ignored.

> +
> + if (evbuf.res == -EAGAIN)
> + tst_res(TPASS, "io_getevents() returned EAGAIN on read event");
> + else
> + tst_res(TFAIL | TTERRNO, "io_getevents() returned with %s instead of EAGAIN",

TTERRNO is not needed.

> + strerror(-evbuf.res));
> +}
> +
> +static struct tst_test test = {
> + .test_all = run,
> + .setup = setup,
> + .cleanup = cleanup,
> + .needs_kconfigs = (const char *[]) {
> + "CONFIG_AIO=y",
> + NULL
> + },
> + .bufs = (struct tst_buffers []) {
> + {&buf, .size = BUF_SIZE},
> + {&cb, .size = sizeof(iocb)},
> + {&iocbs, .size = sizeof(iocb *)},
> + {},
> + }
> +};

--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com