Re: [PATCH 1/4] mm/gup: Add FOLL_INTERRUPTIBLE

From: Peter Xu <peterx@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Linux MM Mailing List <linux-mm@kvack.org>,
	Sean Christopherson <seanjc@google.com>
Subject: Re: [PATCH 1/4] mm/gup: Add FOLL_INTERRUPTIBLE
Date: Thu, 7 Jul 2022 11:06:49 -0400	[thread overview]
Message-ID: <Ysb2iW/MniHX6BXL@xz-m1.local> (raw)
In-Reply-To: <YsNuMSuneND6KW3o@casper.infradead.org>

On Mon, Jul 04, 2022 at 11:48:17PM +0100, Matthew Wilcox wrote:
> On Wed, Jun 22, 2022 at 05:36:53PM -0400, Peter Xu wrote:
> > +/*
> > + * GUP always responds to fatal signals.  When FOLL_INTERRUPTIBLE is
> > + * specified, it'll also respond to generic signals.  The caller of GUP
> > + * that has FOLL_INTERRUPTIBLE should take care of the GUP interruption.
> > + */
> > +static bool gup_signal_pending(unsigned int flags)
> > +{
> > +	if (fatal_signal_pending(current))
> > +		return true;
> > +
> > +	if (!(flags & FOLL_INTERRUPTIBLE))
> > +		return false;
> > +
> > +	return signal_pending(current);
> > +}
> 
> This should resemble signal_pending_state() more closely, if indeed not
> be a wrapper of signal_pending_state().

Could you be more specific?  Note that the only thing that should affect
the signal handling here is FOLL_INTERRUPTIBLE, we don't allow anything
else being passed in, e.g. we don't take TASK_INTERRUPTIBLE or TASK_*.

Thanks,

-- 
Peter Xu