linux-kernel - Re: [PATCH] Coccinelle: Add a SmPL script for the reconsideration of redundant dev

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Message-ID: <alpine.DEB.2.21.1906202046550.3087@hadrien>
Date:   Thu, 20 Jun 2019 20:48:23 +0200 (CEST)
From:   Julia Lawall <julia.lawall@...6.fr>
To:     Markus Elfring <Markus.Elfring@....de>
cc:     kernel-janitors@...r.kernel.org,
        Gilles Muller <Gilles.Muller@...6.fr>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Coccinelle <cocci@...teme.lip6.fr>,
        LKML <linux-kernel@...r.kernel.org>,
        Ding Xiang <dingxiang@...s.chinamobile.com>
Subject: Re: [PATCH] Coccinelle: Add a SmPL script for the reconsideration
 of redundant dev_err() calls



On Thu, 20 Jun 2019, Markus Elfring wrote:

> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Thu, 20 Jun 2019 19:12:53 +0200
>
> The function “devm_ioremap_resource” contains appropriate error reporting.
> Thus it can be questionable to present another error message
> at other places.
>
> Provide design options for the adjustment of affected source code
> by the means of the semantic patch language (Coccinelle software).
>
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  .../coccinelle/misc/redundant_dev_err.cocci   | 53 +++++++++++++++++++
>  1 file changed, 53 insertions(+)
>  create mode 100644 scripts/coccinelle/misc/redundant_dev_err.cocci
>
> diff --git a/scripts/coccinelle/misc/redundant_dev_err.cocci b/scripts/coccinelle/misc/redundant_dev_err.cocci
> new file mode 100644
> index 000000000000..aeb228280276
> --- /dev/null
> +++ b/scripts/coccinelle/misc/redundant_dev_err.cocci
> @@ -0,0 +1,53 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/// Reconsider a function call for redundant error reporting.
> +//
> +// Keywords: dev_err redundant device error messages
> +// Confidence: Medium
> +
> +virtual patch
> +virtual context
> +virtual org
> +virtual report
> +
> +@...play depends on context@
> +expression e;
> +@@
> + e = devm_ioremap_resource(...);
> + if (IS_ERR(e))
> + {
> +*   dev_err(...);
> +    return (...);
> + }

Why do you assume that there is exactly one dev_err and one return after
the test?

> +
> +@...etion depends on patch@
> +expression e;
> +@@
> + e = devm_ioremap_resource(...);
> + if (IS_ERR(e))
> +-{
> +-   dev_err(...);
> +    return (...);
> +-}
> +
> +@or depends on org || report@
> +expression e;
> +position p;
> +@@
> + e = devm_ioremap_resource(...);
> + if (IS_ERR(e))
> + {
> +    dev_err@p(...);
> +    return (...);
> + }
> +
> +@...ipt:python to_do depends on org@
> +p << or.p;
> +@@
> +coccilib.org.print_todo(p[0],
> +                        "WARNING: An error message is probably not needed here because the previously called function contains appropriate error reporting.")

"the previously called function" would be better as
"devm_ioremap_resource".

julia

> +
> +@...ipt:python reporting depends on report@
> +p << or.p;
> +@@
> +coccilib.report.print_report(p[0],
> +                             "WARNING: An error message is probably not needed here because the previously called function contains appropriate error reporting.")
> --
> 2.22.0
>
>