Re: [LTP] [PATCH v3] io_submit04: Add test case for RWF_NOWAIT flag

Andrea Cervesato via ltp
2026-01-05T12:54:16Z

Hi!

On Wed Dec 24, 2025 at 9:49 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 | 86 +++++++++++++++++++
> 5 files changed, 133 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;
> +};
> +
> +#ifndef HAVE_STRUCT_IOCB_AIO_RW_FLAGS
> +typedef struct iocb_fallback iocb;
> +#else
> +typedef struct iocb iocb;
> +#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..bae89828a
> --- /dev/null
> +++ b/testcases/kernel/syscalls/io_submit/io_submit04.c
> @@ -0,0 +1,86 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2025 Wei Gao <wegao@suse.com>
> + */
> +
> +/*\
> + * Test iocb RWF_* flags support: RWF_NOWAIT
> + *
> + * Checks if an asynchronous read operation with RWF_NOWAIT on a blocking
> + * resource (empty pipe) fails immediately with -EAGAIN.

We can write it better:

/*\
* 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"
> +
> +static int fd[2];
> +static char buf[100];
> +
> +static aio_context_t ctx;
> +static iocb cb;
> +static iocb *iocbs[] = {&cb};

Data that is passed to syscalls should be initialized via tst_test.bufs

> +
> +static inline void io_prep_option(iocb *cb, int fd, void *buf,
> + size_t count, long long offset, unsigned int opcode)
> +{
> + memset(cb, 0, sizeof(*cb));
> + cb->aio_fildes = fd;
> + cb->aio_lio_opcode = opcode;
> + cb->aio_buf = (uint64_t)buf;
> + cb->aio_offset = offset;
> + cb->aio_nbytes = count;
> + cb->aio_rw_flags = RWF_NOWAIT;
> +}
> +
> +static void setup(void)
> +{
> + TST_EXP_PASS_SILENT(tst_syscall(__NR_io_setup, 1, &ctx));
> + SAFE_PIPE(fd);
> + io_prep_option(&cb, fd[0], buf, sizeof(buf), 0, IOCB_CMD_PREAD);
> +}
> +
> +static void cleanup(void)
> +{
> + if (fd[0])
> + SAFE_CLOSE(fd[0]);
> +
> + if (fd[1])
> + SAFE_CLOSE(fd[1]);
> +
> + 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 == nr)
> + tst_res(TPASS, "io_submit() pass");
> + else
> + tst_res(TFAIL | TTERRNO, "io_submit() returns %ld, expected %ld", TST_RET, nr);

Our goal is to verify that io_getevents() returns EAGAIN, so we can just:

if (TST_RET != nr) {
tst_res(TBROK | TTERRNO, "io_submit() returns %ld, expected %ld", TST_RET, nr);
return;
}

We return because if io_submit() fails there's nothing to do more.

> +
> + tst_syscall(__NR_io_getevents, ctx, 1, 1, &evbuf, &timeout);
> +
> + if (evbuf.res == -EAGAIN)
> + tst_res(TINFO, "io_submit RWF_NOWAIT flag check pass");

Why TINFO if we are testing this feature? Also the message is not giving
any information of io_getevents(). We can just (look below)...

> + else
> + tst_res(TFAIL | TTERRNO, "io_submit expect EAGAIN, but get %s", strerror(-evbuf.res));
> +
> +}

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", strerror(-evbuf.res));

> +
> +static struct tst_test test = {
> + .test_all = run,
> + .needs_kconfigs = (const char *[]) {
> + "CONFIG_AIO=y",
> + NULL
> + },
> + .setup = setup,
> + .cleanup = cleanup,
> +};

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