[PATCH v3] scripts/checkpatch.pl: remove _deferred and _deferred_once false warning

[Maninder Singh]

with commit 98e35f5894cf ("printk: git rid of [sched_delayed] message for
printk_deferred") printk_deferred and printk_deferred_once requires
LOGLEVEL in argument, but checkpatch.pl was not fixed and still reports
it as warning:

WARNING: Possible unnecessary KERN_ALERT
printk_deferred(KERN_ALERT "checking deferred\n");

As suggested by Andy, made 2 functions from logFunction.

1. logFunction: with all checks
2. logFunctionCore: without printk(?:_ratelimited|_once|_deferred) checking

and call logFunctionCore instead of logFunction for checking of loglevel,
which will exclude checking of printk(?:_ratelimited|_once|_deferred).

This way, there is no need to maintain same stanza at multipe places
for removing printk flavours.

Co-developed-by: Vaneet Narang <v.narang@xxxxxxxxxxx>
Signed-off-by: Vaneet Narang <v.narang@xxxxxxxxxxx>
Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx>
---
v1 -> v2: made 2 functions to remove _deferred and _deferred_once
	as suggested by Andy Whitcroft.
v2-> v3: updated commit message with info of change in printk_deferred.
	https://lkml.org/lkml/2022/2/2/61

 scripts/checkpatch.pl | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index b01c36a15d9d..a6fa0c7360be 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -584,8 +584,7 @@ our $typeTypedefs = qr{(?x:
 
 our $zero_initializer = qr{(?:(?:0[xX])?0+$Int_type?|NULL|false)\b};
 
-our $logFunctions = qr{(?x:
-	printk(?:_ratelimited|_once|_deferred_once|_deferred|)|
+our $logFunctionsCore = qr{(?x:
 	(?:[a-z0-9]+_){1,2}(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|)|
 	TP_printk|
 	WARN(?:_RATELIMIT|_ONCE|)|
@@ -594,6 +593,11 @@ our $logFunctions = qr{(?x:
 	seq_vprintf|seq_printf|seq_puts
 )};
 
+our $logFunctions = qr{(?x:
+	printk(?:_ratelimited|_once|_deferred_once|_deferred|)|
+	$logFunctionsCore
+)};
+
 our $allocFunctions = qr{(?x:
 	(?:(?:devm_)?
 		(?:kv|k|v)[czm]alloc(?:_array)?(?:_node)? |
@@ -6298,8 +6302,7 @@ sub process {
 		}
 
 # check for logging functions with KERN_<LEVEL>
-		if ($line !~ /printk(?:_ratelimited|_once)?\s*\(/ &&
-		    $line =~ /\b$logFunctions\s*\(.*\b(KERN_[A-Z]+)\b/) {
+		if ($line =~ /\b$logFunctionsCore\s*\(.*\b(KERN_[A-Z]+)\b/) {
 			my $level = $1;
 			if (WARN("UNNECESSARY_KERN_LEVEL",
 				 "Possible unnecessary $level\n" . $herecurr) &&
-- 
2.17.1