Subject: Re: [RFC][PATCH v2 7/7] checkpatch: add pF/pf deprecation warning

From: Joe Perches <[email-masked]>
Date: Wed, 20 Sep 2017 10:38:58 -0700

On Thu, 2017-09-21 at 01:29 +0900, Sergey Senozhatsky wrote:
> We deprecated '%pF/%pf' printk specifiers, since '%pS/%ps' is now smart
> enough to handle function pointer dereference on platforms where such
> dereference is required.
> 
> checkpatch warning example:
> 
> WARNING: Use '%pS/%ps' instead. This pointer extension was deprecated: '%pF'

If this series is accepted,  I think this message
is unclear and would prefer something like:
---
scripts/checkpatch.pl | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index dd2c262aebbf..71f3273d5913 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -5762,18 +5762,25 @@ sub process {
 		        for (my $count = $linenr; $count <= $lc; $count++) {
 				my $fmt = get_quoted_string($lines[$count - 1], raw_line($count, 0));
 				$fmt =~ s/%%//g;
-				if ($fmt =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGNO]).)/) {
+				if ($fmt =~ /(\%[\*\d\.]*p(?![\WSsBKRraEhMmIiUDdgVCbGNO]).)/) {
 					$bad_extension = $1;
 					last;
 				}
 			}
 			if ($bad_extension ne "") {
 				my $stat_real = raw_line($linenr, 0);
+				my $ext_type = "Invalid";
+				my $use = "";
 				for (my $count = $linenr + 1; $count <= $lc; $count++) {
 					$stat_real = $stat_real . "\n" . raw_line($count, 0);
 				}
+				if ($bad_extension =~ /p[Ff]/i) {
+					$ext_type = "Deprecated";
+					$use = " - use %pS instead";
+					$use =~ s/pS/ps/ if ($bad_extension =~ /pf/);
+				}
 				WARN("VSPRINTF_POINTER_EXTENSION",
-				     "Invalid vsprintf pointer extension '$bad_extension'\n" . "$here\n$stat_real\n");
+				     "$ext_type vsprintf pointer extension '$bad_extension'$use\n" . "$here\n$stat_real\n");
 			}
 		}