Re: [Cocci] [PATCH 1/2] Coccinelle: extend memdup_user transformation with GFP_USER

[Julia Lawall]

On Sat, 6 Jun 2020, Denis Efremov wrote:

>
>
> On 6/6/20 11:24 AM, Julia Lawall wrote:
> >
> >
> > On Sat, 30 May 2020, Denis Efremov wrote:
> >
> >> Match GFP_USER allocations with memdup_user.cocci rule.
> >> Commit 6c2c97a24f09 ("memdup_user(): switch to GFP_USER") switched
> >> memdup_user() from GFP_KERNEL to GFP_USER. In most cases it is still
> >> a good idea to use memdup_user() for GFP_KERNEL allocations. The
> >> motivation behind altering memdup_user() to GFP_USER is here:
> >> https://lkml.org/lkml/2018/1/6/333
> >
> > Should the rule somehow document the cases in which memdup_user should now
> > not be used?
> >
> > julia
> >
> >
> >>
> >> Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
> >> ---
> >>  scripts/coccinelle/api/memdup_user.cocci | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/scripts/coccinelle/api/memdup_user.cocci b/scripts/coccinelle/api/memdup_user.cocci
> >> index c809ab10bbce..49f487e6a5c8 100644
> >> --- a/scripts/coccinelle/api/memdup_user.cocci
> >> +++ b/scripts/coccinelle/api/memdup_user.cocci
> >> @@ -20,7 +20,7 @@ expression from,to,size;
> >>  identifier l1,l2;
> >>  @@
> >>
> >> --  to = \(kmalloc\|kzalloc\)(size,GFP_KERNEL);
> >> +-  to = \(kmalloc\|kzalloc\)(size,\(GFP_KERNEL\|GFP_USER\));
>
> Actually, we can add optional __GFP_NOWARN here to match such cases as:
> GFP_KERNEL | __GFP_NOWARN
>
> However, I don't know how to express it in elegant way. Something like?
> (
> -  to = \(kmalloc\|kzalloc\)(size,\(GFP_KERNEL\|GFP_USER\));
> |
> -  to = \(kmalloc\|kzalloc\)(size, GFP_KERNEL|__GFP_NOWARN);
> |
> -  to = \(kmalloc\|kzalloc\)(size, GFP_USER|__GFP_NOWARN);
> )

I guess you could do:

\(GFP_KERNEL\|GFP_USER\|\(GFP_KERNEL\|GFP_USER\)|__GFP_NOWARN\)

julia