linux-kernel - Re: [PATCH] Coccinelle: Reduce duplicate code for patch rules of memdup

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Message-ID: <alpine.DEB.2.22.394.2008091324530.2450@hadrien>
Date:   Sun, 9 Aug 2020 13:25:34 +0200 (CEST)
From:   Julia Lawall <julia.lawall@...ia.fr>
To:     Markus Elfring <Markus.Elfring@....de>
cc:     Denis Efremov <efremov@...ux.com>,
        Coccinelle <cocci@...teme.lip6.fr>,
        Gilles Muller <Gilles.Muller@...6.fr>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] Coccinelle: Reduce duplicate code for patch rules of
 memdup_user.cocci



On Sun, 9 Aug 2020, Markus Elfring wrote:

> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Sun, 9 Aug 2020 11:11:20 +0200
>
> Another patch rule was added. A bit of code was copied from a previous
> SmPL rule for this change specification.
>
> * Thus reduce duplicate code by using another SmPL disjunction.

I don't care about this issue.

>
> * Increase the precision a bit for desired source code adjustments.

This gives no information.  If you explain the improvement in an
understandable way, I will consider whether it is useful to take the
patch.

julia

> Fixes: 9c568dbd677bcfc975220d3157c89c48669a23e3 ("coccinelle: api: extend memdup_user rule with vmemdup_user()")
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  scripts/coccinelle/api/memdup_user.cocci | 44 +++++++++---------------
>  1 file changed, 16 insertions(+), 28 deletions(-)
>
> diff --git a/scripts/coccinelle/api/memdup_user.cocci b/scripts/coccinelle/api/memdup_user.cocci
> index e01e95108405..7cf698b4e925 100644
> --- a/scripts/coccinelle/api/memdup_user.cocci
> +++ b/scripts/coccinelle/api/memdup_user.cocci
> @@ -27,34 +27,22 @@ expression from,to,size;
>  identifier l1,l2;
>  position p : script:python() { relevant(p) };
>  @@
> -
> --  to = \(kmalloc@p\|kzalloc@p\)
> --		(size,\(GFP_KERNEL\|GFP_USER\|
> --		      \(GFP_KERNEL\|GFP_USER\)|__GFP_NOWARN\));
> -+  to = memdup_user(from,size);
> -   if (
> --      to==NULL
> -+      IS_ERR(to)
> -                 || ...) {
> -   <+... when != goto l1;
> --  -ENOMEM
> -+  PTR_ERR(to)
> -   ...+>
> -   }
> --  if (copy_from_user(to, from, size) != 0) {
> --    <+... when != goto l2;
> --    -EFAULT
> --    ...+>
> --  }
> -
> -@...ends on patch@
> -expression from,to,size;
> -identifier l1,l2;
> -position p : script:python() { relevant(p) };
> -@@
> -
> --  to = \(kvmalloc@p\|kvzalloc@p\)(size,\(GFP_KERNEL\|GFP_USER\));
> -+  to = vmemdup_user(from,size);
> + to =
> +(
> +-     \(kmalloc@p\|kzalloc@p\)
> ++     memdup_user
> +      (
> +-      size, \( \(GFP_KERNEL\|GFP_USER\) \| \(GFP_KERNEL\|GFP_USER\)|__GFP_NOWARN \)
> ++      from, size
> +      )
> +|
> +-     \(kvmalloc@p\|kvzalloc@p\)
> ++     vmemdup_user
> +      (
> +-      size, \(GFP_KERNEL\|GFP_USER\)
> ++      from, size
> +      )
> +);
>     if (
>  -      to==NULL
>  +      IS_ERR(to)
> --
> 2.28.0
>
>