The patch titled
Subject: checkpatch: check for functions with 'passed by value' structs or unions
has been added to the -mm tree. Its filename is
checkpatch-check-for-functions-with-passed-by-value-structs-or-unions.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/checkpatch-check-for-functions-with-passed-by-value-structs-or-unions.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/checkpatch-check-for-functions-with-passed-by-value-structs-or-unions.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Joe Perches <joe@xxxxxxxxxxx>
Subject: checkpatch: check for functions with 'passed by value' structs or unions
I was cc'd on a patch where structs were passed by value instead of using
pointers to the structs. This can cause defects when the called function
modifies the 'passed by value' struct instead of the calling function's
struct.
There are what seems to be some false positives for a few of the .h files
in include/linux/... where the false positives are for very small structs
where the indirection via a pointer might be slower than than the passed
by value use.
Link: http://lkml.kernel.org/r/84972e19138f1f8eafe74c6b5f1ad874f8525706.camel@xxxxxxxxxxx
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
scripts/checkpatch.pl | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)
--- a/scripts/checkpatch.pl~checkpatch-check-for-functions-with-passed-by-value-structs-or-unions
+++ a/scripts/checkpatch.pl
@@ -6092,8 +6092,10 @@ sub process {
# check for function definitions
if ($perl_version_ok &&
defined $stat &&
- $stat =~ /^.\s*(?:$Storage\s+)?$Type\s*($Ident)\s*$balanced_parens\s*{/s) {
+ $stat =~ /^.\s*(?:$Storage\s+)?$Type\s*($Ident)\s*$balanced_parens\s*([\{;])/s) {
$context_function = $1;
+ my $args = $2;
+ my $term = $3;
# check for multiline function definition with misplaced open brace
my $ok = 0;
@@ -6104,12 +6106,26 @@ sub process {
$herectx .= $rl . "\n";
$ok = 1 if ($rl =~ /^[ \+]\{/);
$ok = 1 if ($rl =~ /\{/ && $n == 0);
- last if $rl =~ /^[ \+].*\{/;
+ last if ($rl =~ /^[ \+].*[\{;]/);
}
- if (!$ok) {
+ if (!$ok && $term eq '{') {
ERROR("OPEN_BRACE",
"open brace '{' following function definitions go on the next line\n" . $herectx);
}
+
+# check for 'passed by value' uses of a struct or a union that might
+# be better 'passed by reference'
+
+ while ($args =~ /(?:$Storage\s+)?($Type)\s*($Ident(?:\s*\[\s*\])?)?\s*,?/g) {
+ my $type = trim($1);
+ my $ident = defined($2) ? trim($2) : "";
+ if ($type =~ /\b(?:union|struct)\b/ &&
+ !($type =~ /(?:\*|\bconst|\])$/ ||
+ $ident =~ /\]$/)) {
+ WARN("AGGREGATE_BY_VALUE",
+ "Unusual 'passed by value' use of '$type'\n" . $herectx);
+ }
+ }
}
# checks for new __setup's
_
Patches currently in -mm which might be from joe@xxxxxxxxxxx are
spdxcheck-work-with-current-head-licenses-directory.patch
checkpatch-add-a-strict-test-for-structs-with-bool-member-definitions.patch
checkpatch-add-fix-for-concatenated_string-and-string_fragments.patch
checkpatch-improve-runtime-execution-speed-a-little.patch
checkpatch-fix-macro-argument-reuse-test.patch
checkpatch-validate-spdx-license-with-spdxcheckpy.patch
checkpatch-fix-krealloc-reuse-test.patch
checkpatch-check-for-functions-with-passed-by-value-structs-or-unions.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
