[Xen-devel] [PATCH v3 01/11] checkpatch: check for nested (un)?likely() calls

[Denis Efremov <efremov@xxxxxxxxx>]

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


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel