Re: [PATCH 3/3] common/rc: force enable io_uring in _require_io_uring

[Zorro Lang <zlang@redhat.com>]

On Wed, Mar 06, 2024 at 07:43:24AM -0800, Darrick J. Wong wrote:
> On Wed, Mar 06, 2024 at 05:19:35PM +0800, Zorro Lang wrote:
> > If kernel supports io_uring, userspace still can/might disable that
> > supporting by set /proc/sys/kernel/io_uring_disabled=2. Let's set
> > it to 0, to always enable io_uring (ignore error if there's not
> > that file).
> > 
> > Signed-off-by: Zorro Lang <zlang@kernel.org>
> > ---
> >  common/rc | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/common/rc b/common/rc
> > index 50dde313..966c92e3 100644
> > --- a/common/rc
> > +++ b/common/rc
> > @@ -2317,6 +2317,9 @@ _require_aiodio()
> >  # this test requires that the kernel supports IO_URING
> >  _require_io_uring()
> >  {
> > +	# Force enable io_uring if kernel supports it
> > +	sysctl -w kernel.io_uring_disabled=0 &> /dev/null
> 
> _require_XXX functions are supposed to be predicates that _notrun the
> test if XXX isn't configured or available.  Shouldn't this be:

Yeah, that makes sense, I tried to find a place to force enable io_uring,
forgot it's not proper for _require_XXX function.

> 
> 	local io_uring_knob="$(sysctl --values kernel.io_uring_disabled)"
> 	test "$io_uring_knob" -ne 0 && _notrun "io_uring disabled by admin"

And I think I need to change the src/feature.c:check_uring_support() too,
check -EPERM as I did in fsstress.c.

> 
> Alternately -- if it _is_ ok to turn this knob, then there should be a
> cleanup method to put it back after the test.

Yeah, I'm still wondering if we should let fstests touch/set the io_uring_disabled
sysctl. Or we leave this job to the fstests user/wrapper script, fstests just
_notrun if io_uring is off.

Thanks,
Zorro

> 
> --D
> 
> > +
> >  	$here/src/feature -R
> >  	case $? in
> >  	0)
> > -- 
> > 2.43.0
> > 
> > 
>