IS_ERR(), IS_ERR_OR_NULL(), IS_ERR_VALUE() and WARN*() already contain unlikely() optimization internally. Thus, there is no point in calling these functions and defines 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-info@xxxxxxxxx/ Signed-off-by: Denis Efremov <efremov@xxxxxxxxx> Cc: Joe Perches <joe@xxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx> --- scripts/checkpatch.pl | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 93a7edfe0f05..56969ce06df4 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6480,6 +6480,12 @@ sub process { "Using $1 should generally have parentheses around the comparison\n" . $herecurr); } +# nested likely/unlikely calls + if ($line =~ /\b(?:(?:un)?likely)\s*\(\s*!?\s*(IS_ERR(?:_OR_NULL|_VALUE)?|WARN)/) { + WARN("LIKELY_MISUSE", + "nested (un)?likely() calls, $1 already uses unlikely() internally\n" . $herecurr); + } + # whine mightly about in_atomic if ($line =~ /\bin_atomic\s*\(/) { if ($realfile =~ m@^drivers/@) { -- 2.21.0
