checkpatch: Prefer seq_puts to seq_printf

Add a check for seq_printf use with a constant format without additional
arguments.  Suggest seq_puts instead.
Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -628,6 +628,13 @@ sub sanitise_line {
 	return $res;
 }
 
+sub get_quoted_string {
+	my ($line, $rawline) = @_;
+
+	return "" if ($line !~ m/(\"[X]+\")/g);
+	return substr($rawline, $-[0], $+[0] - $-[0]);
+}
+
 sub ctx_statement_block {
 	my ($linenr, $remain, $off) = @_;
 	my $line = $linenr - 1;
@@ -3373,6 +3380,15 @@ sub process {
 			     "struct spinlock should be spinlock_t\n" . $herecurr);
 		}
 
+# check for seq_printf uses that could be seq_puts
+		if ($line =~ /\bseq_printf\s*\(/) {
+			my $fmt = get_quoted_string($line, $rawline);
+			if ($fmt !~ /[^\\]\%/) {
+				WARN("PREFER_SEQ_PUTS",
+				     "Prefer seq_puts to seq_printf\n" . $herecurr);
+			}
+		}
+
 # Check for misused memsets
 		if ($^V && $^V ge 5.10.0 &&
 		    defined $stat &&