[PATCH v2] coccinnelle: Remove ptr_ret script

[PATCH v2] coccinnelle: Remove ptr_ret script

[Maxime Ripard]

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.

Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Julia Lawall <julia.lawall@inria.fr>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---

Changes from v1:
  - Collected the tags

 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
-
-@depends on patch@
-expression ptr;
-@@
-
-- if (IS_ERR(ptr)) return PTR_ERR(ptr); else return 0;
-+ return PTR_ERR_OR_ZERO(ptr);
-
-@depends on patch@
-expression ptr;
-@@
-
-- if (IS_ERR(ptr)) return PTR_ERR(ptr); return 0;
-+ return PTR_ERR_OR_ZERO(ptr);
-
-@depends 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
-
-@script:python depends on org@
-p << r1.p1;
-@@
-
-coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
-
-
-@script:python depends on org@
-p << r2.p2;
-@@
-
-coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
-
-@script:python depends on org@
-p << r3.p3;
-@@
-
-coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
-
-@script:python depends on report@
-p << r1.p1;
-@@
-
-coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
-
-@script:python depends on report@
-p << r2.p2;
-@@
-
-coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
-
-@script:python depends on report@
-p << r3.p3;
-@@
-
-coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
-- 
2.28.0

Re: [PATCH v2] coccinnelle: Remove ptr_ret script

[Julia Lawall]

On Tue, 15 Dec 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.
>
> Acked-by: Jani Nikula <jani.nikula@intel.com>
> Acked-by: Thierry Reding <treding@nvidia.com>
> Acked-by: Julia Lawall <julia.lawall@inria.fr>
> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Reviewed-by: Mark Brown <broonie@kernel.org>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Applied

> ---
>
> Changes from v1:
>   - Collected the tags
>
>  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
> -
> -@depends on patch@
> -expression ptr;
> -@@
> -
> -- if (IS_ERR(ptr)) return PTR_ERR(ptr); else return 0;
> -+ return PTR_ERR_OR_ZERO(ptr);
> -
> -@depends on patch@
> -expression ptr;
> -@@
> -
> -- if (IS_ERR(ptr)) return PTR_ERR(ptr); return 0;
> -+ return PTR_ERR_OR_ZERO(ptr);
> -
> -@depends 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
> -
> -@script:python depends on org@
> -p << r1.p1;
> -@@
> -
> -coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -
> -@script:python depends on org@
> -p << r2.p2;
> -@@
> -
> -coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@script:python depends on org@
> -p << r3.p3;
> -@@
> -
> -coccilib.org.print_todo(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@script:python depends on report@
> -p << r1.p1;
> -@@
> -
> -coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@script:python depends on report@
> -p << r2.p2;
> -@@
> -
> -coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> -
> -@script:python depends on report@
> -p << r3.p3;
> -@@
> -
> -coccilib.report.print_report(p[0], "WARNING: PTR_ERR_OR_ZERO can be used")
> --
> 2.28.0
>
>