Re: [PATCH v4 4/6] io_uring: rsrc: avoid use of vmas parameter in pin_user_pages()

[David Hildenbrand]

On 18.04.23 17:55, David Hildenbrand wrote:
> On 18.04.23 17:49, Lorenzo Stoakes wrote:
> > We are shortly to remove pin_user_pages(), and instead perform the required
> > VMA checks ourselves. In most cases there will be a single VMA so this
> > should caues no undue impact on an already slow path.
> >
> > Doing this eliminates the one instance of vmas being used by
> > pin_user_pages().
> >
> > Suggested-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> > Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
> > ---
> >    io_uring/rsrc.c | 55 ++++++++++++++++++++++++++++---------------------
> >    1 file changed, 31 insertions(+), 24 deletions(-)
> >
> > diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
> > index 7a43aed8e395..3a927df9d913 100644
> > --- a/io_uring/rsrc.c
> > +++ b/io_uring/rsrc.c
> > @@ -1138,12 +1138,37 @@ static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
> >    	return ret;
> >    }
> >    
> > +static int check_vmas_locked(unsigned long addr, unsigned long len)
>
> TBH, the whole "_locked" suffix is a bit confusing.
>
> I was wondering why you'd want to check whether the VMAs are locked ...

FWIW, "check_vmas_compatible_locked" might be better. But the "_locked" 
is still annoying.

--
Thanks,

David / dhildenb