linux-kernel - Re: [PATCH] coccinnelle: Remove ptr

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Message-ID: <alpine.DEB.2.21.2001071106420.3004@hadrien>
Date:   Tue, 7 Jan 2020 11:06:56 +0100 (CET)
From:   Julia Lawall <julia.lawall@...ia.fr>
To:     Maxime Ripard <maxime@...no.tech>
cc:     Julia.Lawall@...6.fr, Gilles.Muller@...6.fr, nicolas.palix@...g.fr,
        michal.lkml@...kovi.net, cocci@...teme.lip6.fr,
        linux-kernel@...r.kernel.org,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH] coccinnelle: Remove ptr_ret script



On Tue, 7 Jan 2020, Maxime Ripard wrote:

> The ptr_ret script script addresses a number of situations where we end up
> testing an error pointer, and if it's an error returning it, or return 0
> otherwise to transform it into a PTR_ERR_OR_ZERO call.
>
> So it will convert a block like this:
>
> if (IS_ERR(err))
>     return PTR_ERR(err);
>
> return 0;
>
> into
>
> return PTR_ERR_OR_ZERO(err);
>
> While this is technically correct, it has a number of drawbacks. First, it
> merges the error and success path, which will make it harder for a reviewer
> or reader to grasp.
>
> It's also more difficult to extend if we were to add some code between the
> error check and the function return, making the author essentially revert
> that patch before adding new lines, while it would have been a trivial
> addition otherwise for the rewiever.
>
> Therefore, since that script is only about cosmetic in the first place,
> let's remove it since it's not worth it.
>
> Cc: Jani Nikula <jani.nikula@...ux.intel.com>
> Cc: Thierry Reding <thierry.reding@...il.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@...com>
> Cc: Mark Brown <broonie@...nel.org>
> Signed-off-by: Maxime Ripard <maxime@...no.tech>

Acked-by: Julia Lawall <julia.lawall@...ia.fr>

> ---
>  scripts/coccinelle/api/ptr_ret.cocci | 97 ----------------------------
>  1 file changed, 97 deletions(-)
>  delete mode 100644 scripts/coccinelle/api/ptr_ret.cocci
>
> diff --git a/scripts/coccinelle/api/ptr_ret.cocci b/scripts/coccinelle/api/ptr_ret.cocci
> deleted file mode 100644
> index e76cd5d90a8a..000000000000
> --- a/scripts/coccinelle/api/ptr_ret.cocci
> +++ /dev/null
> @@ -1,97 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -///
> -/// Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR
> -///
> -// Confidence: High
> -// Copyright: (C) 2012 Julia Lawall, INRIA/LIP6.
> -// Copyright: (C) 2012 Gilles Muller, INRIA/LiP6.
> -// URL: http://coccinelle.lip6.fr/
> -// Options: --no-includes --include-headers
> -//
> -// Keywords: ERR_PTR, PTR_ERR, PTR_ERR_OR_ZERO
> -// Version min: 2.6.39
> -//
> -
> -virtual context
> -virtual patch
> -virtual org
> -virtual report
> -
> -@...ends on patch@
> -expression ptr;
> -@@
> -
> -- if (IS_ERR(ptr)) return PTR_ERR(ptr); else return 0;
> -+ return PTR_ERR_OR_ZERO(ptr);
> -
> -@...ends on patch@
> -expression ptr;
> -@@
> -
> -- if (IS_ERR(ptr)) return PTR_ERR(ptr); return 0;
> -+ return PTR_ERR_OR_ZERO(ptr);
> -
> -@...ends on patch@
> -expression ptr;
> -@@
> -
> -- (IS_ERR(ptr) ? PTR_ERR(ptr) : 0)
> -+ PTR_ERR_OR_ZERO(ptr)
> -
> -@r1 depends on !patch@
> -expression ptr;
> -position p1;
> -@@
> -
> -* if@p1 (IS_ERR(ptr)) return PTR_ERR(ptr); else return 0;
> -
> -@r2 depends on !patch@
> -expression ptr;
> -position p2;
> -@@
> -
> -* if@p2 (IS_ERR(ptr)) return PTR_ERR(ptr); return 0;
> -
> -@r3 depends on !patch@
> -expression ptr;
> -position p3;
> -@@
> -
> -* IS_ERR@p3(ptr) ? PTR_ERR(ptr) : 0
> -
> -@...ipt:python depends on org@
> -p << r1.p1;
> -@@
> -
> -coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -
> -@...ipt:python depends on org@
> -p << r2.p2;
> -@@
> -
> -coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@...ipt:python depends on org@
> -p << r3.p3;
> -@@
> -
> -coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@...ipt:python depends on report@
> -p << r1.p1;
> -@@
> -
> -coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@...ipt:python depends on report@
> -p << r2.p2;
> -@@
> -
> -coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@...ipt:python depends on report@
> -p << r3.p3;
> -@@
> -
> -coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> --
> 2.24.1
>
>