[PATCH v2] checkpatch.pl: Warn on duplicate sysctl local variable

From: Matteo Croce
Date: Thu May 30 2019 - 21:16:21 EST


Commit 6a33853c5773 ("proc/sysctl: add shared variables for range check")
adds some shared const variables to be used instead of a local copy in
each source file.
Warn when a chunk duplicates one of these values in a ctl_table struct:

$ scripts/checkpatch.pl 0001-test-commit.patch
WARNING: duplicated sysctl range checking value 'zero', consider using the shared one in include/linux/sysctl.h
#27: FILE: arch/arm/kernel/isa.c:48:
+ .extra1 = &zero,

WARNING: duplicated sysctl range checking value 'int_max', consider using the shared one in include/linux/sysctl.h
#28: FILE: arch/arm/kernel/isa.c:49:
+ .extra2 = &int_max,

total: 0 errors, 2 warnings, 14 lines checked

Signed-off-by: Matteo Croce <mcroce@xxxxxxxxxx>
---
scripts/checkpatch.pl | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 342c7c781ba5..629c31435487 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6639,6 +6639,12 @@ sub process {
"unknown module license " . $extracted_string . "\n" . $herecurr);
}
}
+
+# check for sysctl duplicate constants
+ if ($line =~ /\.extra[12]\s*=\s*&(zero|one|int_max|max_int)\b/) {
+ WARN("DUPLICATED_SYSCTL_CONST",
+ "duplicated sysctl range checking value '$1', consider using the shared one in include/linux/sysctl.h\n" . $herecurr);
+ }
}

# If we have no input at all, then there is nothing to report on
--
2.21.0