Re: [PATCH v4 3/3] selftests/tracing: Add hist poll() support test

Masami Hiramatsu
2024-08-17T15:06:25Z

On Fri, 16 Aug 2024 08:04:41 -0600
Shuah Khan <skhan@linuxfoundation.org> wrote:

> On 8/15/24 20:31, Masami Hiramatsu (Google) wrote:
> > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> >
> > Add a testcase for poll() on hist file. This introduces a helper binary
> > to the ftracetest, because there is no good way to reliably execute
> > poll() on hist file.
> >
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > ---
> > Changes in v4:
> > - Use getopt() in poll.c (command options are changed)
> > - Update test code according to the new command options.
> > Changes in v2:
> > - Update poll command to support both of POLLIN and POLLPRI, and timeout.
> > - Identify unsupported stable kernel if poll-in returns soon.
> > - Test both of POLLIN and POLLPRI.
> > ---
> > tools/testing/selftests/ftrace/Makefile | 2 +
> > tools/testing/selftests/ftrace/poll.c | 74 ++++++++++++++++++++
> > .../ftrace/test.d/trigger/trigger-hist-poll.tc | 74 ++++++++++++++++++++
> > 3 files changed, 150 insertions(+)
> > create mode 100644 tools/testing/selftests/ftrace/poll.c
> > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
> >
> > diff --git a/tools/testing/selftests/ftrace/Makefile b/tools/testing/selftests/ftrace/Makefile
> > index a1e955d2de4c..49d96bb16355 100644
> > --- a/tools/testing/selftests/ftrace/Makefile
> > +++ b/tools/testing/selftests/ftrace/Makefile
> > @@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
> > TEST_FILES := test.d settings
> > EXTRA_CLEAN := $(OUTPUT)/logs/*
> >
> > +TEST_GEN_PROGS = poll
> > +
> > include ../lib.mk
> > diff --git a/tools/testing/selftests/ftrace/poll.c b/tools/testing/selftests/ftrace/poll.c
> > new file mode 100644
> > index 000000000000..584f159654b1
> > --- /dev/null
> > +++ b/tools/testing/selftests/ftrace/poll.c
> > @@ -0,0 +1,74 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Simple poll on a file.
> > + *
> > + * Copyright (c) 2024 Google LLC.
> > + */
> > +
> > +#include <errno.h>
> > +#include <fcntl.h>
> > +#include <poll.h>
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <unistd.h>
> > +
> > +#define BUFSIZE 4096
> > +
> > +/*
> > + * Usage:
> > + * poll [-I|-P] [-t timeout] FILE
> > + */
> > +int main(int argc, char *argv[])
> > +{
> > + struct pollfd pfd = {.events = POLLIN};
> > + char buf[BUFSIZE];
> > + int timeout = -1;
> > + int ret, opt;
> > +
> > + while ((opt = getopt(argc, argv, "IPt:")) != -1) {
> > + switch (opt) {
> > + case 'I':
> > + pfd.events = POLLIN;
> > + break;
> > + case 'P':
> > + pfd.events = POLLPRI;
> > + break;
> > + case 't':
> > + timeout = atoi(optarg);
> > + break;
> > + default:
> > + fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
> > + argv[0]);
> > + return -1;
> > + }
> > + }
> > + if (optind >= argc) {
> > + fprintf(stderr, "Error: Polling file is not specified\n");
> > + return -1;
> > + }
> > +
> > + pfd.fd = open(argv[optind], O_RDONLY);
> > + if (pfd.fd < 0) {
> > + fprintf(stderr, "failed to open %s", argv[optind]);
> > + perror("open");
> > + return -1;
> > + }
> > +
> > + /* Reset poll by read if POLLIN is specified. */
> > + if (pfd.events & POLLIN)
> > + do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE);
> > +
> > + ret = poll(&pfd, 1, timeout);
> > + if (ret < 0 && errno != EINTR) {
> > + perror("poll");
> > + return -1;
> > + }
> > + close(pfd.fd);
> > +
> > + /* If timeout happned, return code is 0 */
>
> Looks like you missed this one :) Otherwise looks good to me.
>
Oops, indeed.

> With this fixed
>
> Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

Thanks!

>
> thanks,
> -- Shuah

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>