Re: [PATCH bpf-next v4 2/4] uaccess: Define pagefault lock guard

[Andrii Nakryiko]

On Thu, May 8, 2025 at 3:01 AM Matt Bobrowski <mattbobrowski@xxxxxxxxxx> wrote:
>
> On Wed, May 07, 2025 at 08:40:37AM +0200, Viktor Malik wrote:
> > Define a pagefault lock guard which allows to simplify functions that
> > need to disable page faults.
> >
> > Signed-off-by: Viktor Malik <vmalik@xxxxxxxxxx>
> > ---
> >  include/linux/uaccess.h | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
> > index 7c06f4795670..1beb5b395d81 100644
> > --- a/include/linux/uaccess.h
> > +++ b/include/linux/uaccess.h
> > @@ -296,6 +296,8 @@ static inline bool pagefault_disabled(void)
> >   */
> >  #define faulthandler_disabled() (pagefault_disabled() || in_atomic())
> >
> > +DEFINE_LOCK_GUARD_0(pagefault, pagefault_disable(), pagefault_enable())
>
> I can't help but mention that naming this scope-based cleanup helper
> `pagefault` just seems overly ambiguous. That's just me though...

I do see the concern, but

DEFINE_LOCK_GUARD_0(preempt, preempt_disable(), preempt_enable())
DEFINE_LOCK_GUARD_0(irq, local_irq_disable(), local_irq_enable())

so we are just staying consistent here? But also "guard (against) the
pagefault" does (internally) read somewhat meaningfully, no?