linux-kernel - [PATCH] coccinelle: misc: minmax: suppress patch generation for err returns

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Message-Id: <20210409111902.7561-1-efremov@linux.com>
Date:   Fri,  9 Apr 2021 14:19:02 +0300
From:   Denis Efremov <efremov@...ux.com>
To:     julia.lawall@...ia.fr
Cc:     Denis Efremov <efremov@...ux.com>, cocci@...teme.lip6.fr,
        linux-kernel@...r.kernel.org
Subject: [PATCH] coccinelle: misc: minmax: suppress patch generation for err returns

There is a standard idiom for "if 'ret' holds an error, return it":
	return ret < 0 ? ret : 0;

Developers prefer to keep the things as they are because stylistic
change to "return min(ret, 0);" breaks readability.

Let's suppress automatic generation for this type of patches.

Signed-off-by: Denis Efremov <efremov@...ux.com>
---
 scripts/coccinelle/misc/minmax.cocci | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/scripts/coccinelle/misc/minmax.cocci b/scripts/coccinelle/misc/minmax.cocci
index eccdd3eb3452..fcf908b34f27 100644
--- a/scripts/coccinelle/misc/minmax.cocci
+++ b/scripts/coccinelle/misc/minmax.cocci
@@ -116,16 +116,32 @@ func(...)
 	...>
 }
 
+// Don't generate patches for errcode returns.
+@...code depends on patch@
+position p;
+identifier func;
+expression x;
+binary operator cmp = {<, <=};
+@@
+
+func(...)
+{
+	<...
+	return ((x) cmp@p 0 ? (x) : 0);
+	...>
+}
+
 @pmin depends on patch@
 identifier func;
 expression x, y;
 binary operator cmp = {<=, <};
+position p != errcode.p;
 @@
 
 func(...)
 {
 	<...
--	((x) cmp (y) ? (x) : (y))
+-	((x) cmp@p (y) ? (x) : (y))
 +	min(x, y)
 	...>
 }
-- 
2.30.2