[PATCH v1] checkpatch: Check for invalid return codes

From: Prakruthi Deepak Heragu
Date: Tue Jul 03 2018 - 19:42:12 EST

The only valid integer return is 0, anything else
following "return" should be -ERRCODE or a function. Also, display context
so that the user knows where the return value is incorrect.

There's lots of "return -1;" statements in this patch - it's obscene
that this is used to indicate "some error occurred" in kernel space
rather than a real errno value - even when an existing function
(eg, request_irq) gave you an error code already.

Signed-off-by: Patrick Pannuto <ppannuto@xxxxxxxxxxxxxx>
Signed-off-by: Stepan Moskovchenko <stepanm@xxxxxxxxxxxxxx>
Signed-off-by: Prakruthi Deepak Heragu <pheragu@xxxxxxxxxxxxxx>
Changes in v1:
- Use CHK instead of ERROR
- Rephrase the warning message
- Provide the file name and line number where return value is incorrect

scripts/checkpatch.pl | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a9c0550..2808c27 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6197,6 +6197,12 @@ sub process {
"switch default: should use break\n" . $herectx);

+# check for return codes on error paths
+ if ($line =~ /\breturn\s+-\d+/) {
+ "invalid return value, please return -<APPROPRIATE_ERRNO>\n" . $herecurr);
+ }
# check for gcc specific __FUNCTION__
if ($line =~ /\b__FUNCTION__\b/) {
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