[PATCH] checkpatch: Prefer ftrace over function entry/exit printks

[Joe Perches]

Prefer using ftrace over function entry/exit logging messages.

Warn with various function entry/exit only logging that only
use __func__ with or without descriptive decoration.

Signed-off-by: Joe Perches <j...@perches.com>
---
 scripts/checkpatch.pl | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e6857bdfcb2d..7c95f23352ae 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -507,6 +507,30 @@ our $signature_tags = qr{(?xi:
        Cc:
 )};
 
+our $tracing_logging_tags = qr{(?xi:
+       [=-]*> |
+       <[=-]* |
+       \[ |
+       \] |
+       start |
+       called |
+       entered |
+       entry |
+       enter |
+       in |
+       inside |
+       here |
+       begin |
+       exit |
+       end |
+       done |
+       leave |
+       completed |
+       out |
+       return |
+       [\.\!:\s]*
+)};
+
 sub edit_distance_min {
        my (@arr) = @_;
        my $len = scalar @arr;
@@ -5981,6 +6005,17 @@ sub process {
                             "Prefer using '\"%s...\", __func__' to using 
'$context_function', this function's name, in a string\n" . $herecurr);
                }
 
+# check for unnecessary function tracing like uses
+# This does not use $logFunctions because there are many instances like
+# 'dprintk(FOO, "%s()\n", __func__);' which do not match $logFunctions
+               if ($rawline =~ 
/^\+.*\([^"]*"$tracing_logging_tags{0,3}%s(?:\s*\(\s*\)\s*)?$tracing_logging_tags{0,3}(?:\\n)?"\s*,\s*__func__\s*\)\s*;/)
 {
+                       if (WARN("TRACING_LOGGING",
+                                "Unnecessary ftrace-like logging - prefer 
using ftrace\n" . $herecurr) &&
+                           $fix) {
+                                fix_delete_line($fixlinenr, $rawline);
+                       }
+               }
+
 # check for spaces before a quoted newline
                if ($rawline =~ /^.*\".*\s\\n/) {
                        if (WARN("QUOTED_WHITESPACE_BEFORE_NEWLINE",