lockdep: Add novalidate class for dev->mutex conversion

The conversion of device->sem to device->mutex resulted in lockdep
warnings. Create a novalidate class for now until the driver folks
come up with separate classes. That way we have at least the basic
mutex debugging coverage.

Add a checkpatch error so the usage is reserved for device->mutex.

[ tglx: checkpatch and compile fix for LOCKDEP=n ]

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a4d74344d805..f2bbea900700 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2656,6 +2656,7 @@ sub process {
 # check for semaphores used as mutexes
                 if ($line =~ /^.\s*init_MUTEX_LOCKED\s*\(/) {
                         WARN("consider using a completion\n" . $herecurr);
+
                 }
 # recommend strict_strto* over simple_strto*
                 if ($line =~ /\bsimple_(strto.*?)\s*\(/) {
@@ -2740,6 +2741,16 @@ sub process {
                                 WARN("use of in_atomic() is incorrect outside core kernel code\n" . $herecurr);
                         }
                 }
+
+# check for lockdep_set_novalidate_class
+                if ($line =~ /^.\s*lockdep_set_novalidate_class\s*\(/ ||
+                    $line =~ /__lockdep_no_validate__\s*\)/ ) {
+                        if ($realfile !~ m@^kernel/lockdep@ &&
+                            $realfile !~ m@^include/linux/lockdep@ &&
+                            $realfile !~ m@^drivers/base/core@) {
+                                ERROR("lockdep_no_validate class is reserved for device->mutex.\n" . $herecurr);
+                        }
+                }
         }
 
         # If we have no input at all, then there is nothing to report on