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

[Zorro Lang <zlang@redhat.com>]

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
>