[PATCH] ltp/fsstress: don't fail on io_uring ENOSYS

[PATCH] ltp/fsstress: don't fail on io_uring ENOSYS

[Eric Sandeen]

We might have URING #defined at build time, but be running on a kernel
which does not support it.

For that reason, we should not exit with an error if 
io_uring_queue_init() fails with ENOSYS. We can just note the lack of
support and skip all future io_uring operations.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/ltp/fsstress.c b/ltp/fsstress.c
index 22df5e38..73751935 100644
--- a/ltp/fsstress.c
+++ b/ltp/fsstress.c
@@ -35,6 +35,7 @@ io_context_t	io_ctx;
 #include <liburing.h>
 #define URING_ENTRIES	1
 struct io_uring	ring;
+bool have_io_uring;			/* to indicate runtime availability */
 #endif
 #include <sys/syscall.h>
 #include <sys/xattr.h>
@@ -706,9 +707,15 @@ int main(int argc, char **argv)
 			}
 #endif
 #ifdef URING
+			have_io_uring = true;
+			/* If ENOSYS, just ignore uring, other errors are fatal. */
 			if (io_uring_queue_init(URING_ENTRIES, &ring, 0)) {
-				fprintf(stderr, "io_uring_queue_init failed\n");
-				exit(1);
+				if (errno == ENOSYS) {
+					have_io_uring = false;
+				} else {
+					fprintf(stderr, "io_uring_queue_init failed\n");
+					exit(1);
+				}
 			}
 #endif
 			for (i = 0; !loops || (i < loops); i++)
@@ -720,7 +727,8 @@ int main(int argc, char **argv)
 			}
 #endif
 #ifdef URING
-			io_uring_queue_exit(&ring);
+			if (have_io_uring)
+				io_uring_queue_exit(&ring);
 #endif
 			cleanup_flist();
 			free(freq_table);
@@ -2208,6 +2216,9 @@ do_uring_rw(int opno, long r, int flags)
 	struct iovec	iovec;
 	int		iswrite = (flags & (O_WRONLY | O_RDWR)) ? 1 : 0;
 
+	if (!have_io_uring)
+		return;
+
 	init_pathname(&f);
 	if (!get_fname(FT_REGFILE, r, &f, NULL, NULL, &v)) {
 		if (v)

Re: [PATCH] ltp/fsstress: don't fail on io_uring ENOSYS

[Zorro Lang]

On Thu, Jan 28, 2021 at 03:31:40PM -0600, Eric Sandeen wrote:
> We might have URING #defined at build time, but be running on a kernel
> which does not support it.
> 
> For that reason, we should not exit with an error if 
> io_uring_queue_init() fails with ENOSYS. We can just note the lack of
> support and skip all future io_uring operations.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> index 22df5e38..73751935 100644
> --- a/ltp/fsstress.c
> +++ b/ltp/fsstress.c
> @@ -35,6 +35,7 @@ io_context_t	io_ctx;
>  #include <liburing.h>
>  #define URING_ENTRIES	1
>  struct io_uring	ring;
> +bool have_io_uring;			/* to indicate runtime availability */
>  #endif
>  #include <sys/syscall.h>
>  #include <sys/xattr.h>
> @@ -706,9 +707,15 @@ int main(int argc, char **argv)
>  			}
>  #endif
>  #ifdef URING
> +			have_io_uring = true;
> +			/* If ENOSYS, just ignore uring, other errors are fatal. */

Yes, I thought about if we should do this since rhel8 kernel removed io_uring
support from kernel, but left userspace liburing. But if we do this for io_uring,
should we do the same check the others which can be disabled from kernel? Likes: AIO?

Thanks,
Zorro

>  			if (io_uring_queue_init(URING_ENTRIES, &ring, 0)) {
> -				fprintf(stderr, "io_uring_queue_init failed\n");
> -				exit(1);
> +				if (errno == ENOSYS) {
> +					have_io_uring = false;
> +				} else {
> +					fprintf(stderr, "io_uring_queue_init failed\n");
> +					exit(1);
> +				}
>  			}
>  #endif
>  			for (i = 0; !loops || (i < loops); i++)
> @@ -720,7 +727,8 @@ int main(int argc, char **argv)
>  			}
>  #endif
>  #ifdef URING
> -			io_uring_queue_exit(&ring);
> +			if (have_io_uring)
> +				io_uring_queue_exit(&ring);
>  #endif
>  			cleanup_flist();
>  			free(freq_table);
> @@ -2208,6 +2216,9 @@ do_uring_rw(int opno, long r, int flags)
>  	struct iovec	iovec;
>  	int		iswrite = (flags & (O_WRONLY | O_RDWR)) ? 1 : 0;
>  
> +	if (!have_io_uring)
> +		return;
> +
>  	init_pathname(&f);
>  	if (!get_fname(FT_REGFILE, r, &f, NULL, NULL, &v)) {
>  		if (v)
> 

Re: [PATCH] ltp/fsstress: don't fail on io_uring ENOSYS

[Eryu Guan]

On Fri, Jan 29, 2021 at 04:10:44PM +0800, Zorro Lang wrote:
> On Thu, Jan 28, 2021 at 03:31:40PM -0600, Eric Sandeen wrote:
> > We might have URING #defined at build time, but be running on a kernel
> > which does not support it.
> > 
> > For that reason, we should not exit with an error if 
> > io_uring_queue_init() fails with ENOSYS. We can just note the lack of
> > support and skip all future io_uring operations.
> > 
> > Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> > ---
> > 
> > diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> > index 22df5e38..73751935 100644
> > --- a/ltp/fsstress.c
> > +++ b/ltp/fsstress.c
> > @@ -35,6 +35,7 @@ io_context_t	io_ctx;
> >  #include <liburing.h>
> >  #define URING_ENTRIES	1
> >  struct io_uring	ring;
> > +bool have_io_uring;			/* to indicate runtime availability */
> >  #endif
> >  #include <sys/syscall.h>
> >  #include <sys/xattr.h>
> > @@ -706,9 +707,15 @@ int main(int argc, char **argv)
> >  			}
> >  #endif
> >  #ifdef URING
> > +			have_io_uring = true;
> > +			/* If ENOSYS, just ignore uring, other errors are fatal. */
> 
> Yes, I thought about if we should do this since rhel8 kernel removed io_uring
> support from kernel, but left userspace liburing. But if we do this for io_uring,
> should we do the same check the others which can be disabled from kernel? Likes: AIO?

io_uring is a relative new interface, and it's quite possible that some
distros don't support it. aio has been there for a long time, and is
very unlikely disabled. If we really need to do the same check for aio,
we could do it in another patch I guess.

Thanks,
Eryu

Re: [PATCH] ltp/fsstress: don't fail on io_uring ENOSYS

[Zorro Lang]

On Sun, Jan 31, 2021 at 10:30:07PM +0800, Eryu Guan wrote:
> On Fri, Jan 29, 2021 at 04:10:44PM +0800, Zorro Lang wrote:
> > On Thu, Jan 28, 2021 at 03:31:40PM -0600, Eric Sandeen wrote:
> > > We might have URING #defined at build time, but be running on a kernel
> > > which does not support it.
> > > 
> > > For that reason, we should not exit with an error if 
> > > io_uring_queue_init() fails with ENOSYS. We can just note the lack of
> > > support and skip all future io_uring operations.
> > > 
> > > Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> > > ---
> > > 
> > > diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> > > index 22df5e38..73751935 100644
> > > --- a/ltp/fsstress.c
> > > +++ b/ltp/fsstress.c
> > > @@ -35,6 +35,7 @@ io_context_t	io_ctx;
> > >  #include <liburing.h>
> > >  #define URING_ENTRIES	1
> > >  struct io_uring	ring;
> > > +bool have_io_uring;			/* to indicate runtime availability */
> > >  #endif
> > >  #include <sys/syscall.h>
> > >  #include <sys/xattr.h>
> > > @@ -706,9 +707,15 @@ int main(int argc, char **argv)
> > >  			}
> > >  #endif
> > >  #ifdef URING
> > > +			have_io_uring = true;
> > > +			/* If ENOSYS, just ignore uring, other errors are fatal. */
> > 
> > Yes, I thought about if we should do this since rhel8 kernel removed io_uring
> > support from kernel, but left userspace liburing. But if we do this for io_uring,
> > should we do the same check the others which can be disabled from kernel? Likes: AIO?
> 
> io_uring is a relative new interface, and it's quite possible that some
> distros don't support it. aio has been there for a long time, and is
> very unlikely disabled. If we really need to do the same check for aio,
> we could do it in another patch I guess.

OK, I just have this one question, this patch looks good to me.

Thanks,
Zorro

> 
> Thanks,
> Eryu
>