IS_ERR, IS_ERR_OR_NULL, IS_ERR_VALUE already contain unlikely optimization internally. Thus, there is no point in calling these functions under likely/unlikely.
This check is based on the coccinelle rule developed by Enrico Weigelt https://lore.kernel.org/lkml/1559767582-11081-1-git-send-email-i...@metux.net/ Signed-off-by: Denis Efremov <efre...@linux.com> --- scripts/checkpatch.pl | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 93a7edfe0f05..81dace5ceea5 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6480,6 +6480,13 @@ sub process { "Using $1 should generally have parentheses around the comparison\n" . $herecurr); } +# nested likely/unlikely calls + if ($perl_version_ok && + $line =~ /\b(?:(?:un)?likely)\s*\(!?\s*(IS_ERR(?:_OR_NULL|_VALUE)?)\s*${balanced_parens}\s*\)/) { + WARN("LIKELY_MISUSE", + "nested (un)?likely calls, unlikely already used in $1 internally\n" . $herecurr); + } + # whine mightly about in_atomic if ($line =~ /\bin_atomic\s*\(/) { if ($realfile =~ m@^drivers/@) { -- 2.21.0
