From 1704f47b50b5d9e1b825e43e1baaf2c5897baf03 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 19 Mar 2010 01:37:42 +0100 Subject: [PATCH] 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 Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 1 + include/linux/lockdep.h | 8 ++++++++ kernel/lockdep.c | 5 +++++ scripts/checkpatch.pl | 11 +++++++++++ 4 files changed, 25 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index cf507a7..4c5be85 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -559,6 +559,7 @@ void device_initialize(struct device *dev) kobject_init(&dev->kobj, &device_ktype); INIT_LIST_HEAD(&dev->dma_pools); mutex_init(&dev->mutex); + lockdep_set_novalidate_class(&dev->mutex); spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); device_pm_init(dev); diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index a03977a9..06aed83 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -44,6 +44,8 @@ struct lock_class_key { struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; }; +extern struct lock_class_key __lockdep_no_validate__; + #define LOCKSTAT_POINTS 4 /* @@ -270,6 +272,9 @@ extern void lockdep_init_map(struct lockdep_map *lock, const char *name, #define lockdep_set_subclass(lock, sub) \ lockdep_init_map(&(lock)->dep_map, #lock, \ (lock)->dep_map.key, sub) + +#define lockdep_set_novalidate_class(lock) \ + lockdep_set_class(lock, &__lockdep_no_validate__) /* * Compare locking classes */ @@ -354,6 +359,9 @@ static inline void lockdep_on(void) #define lockdep_set_class_and_subclass(lock, key, sub) \ do { (void)(key); } while (0) #define lockdep_set_subclass(lock, sub) do { } while (0) + +#define lockdep_set_novalidate_class(lock) do { } while (0) + /* * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP * case since the result is not well defined and the caller should rather diff --git a/kernel/lockdep.c b/kernel/lockdep.c index ec21304..5428679 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2711,6 +2711,8 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name, } EXPORT_SYMBOL_GPL(lockdep_init_map); +struct lock_class_key __lockdep_no_validate__; + /* * This gets called for every mutex_lock*()/spin_lock*() operation. * We maintain the dependency maps and validate the locking attempt: @@ -2745,6 +2747,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, return 0; } + if (lock->key == &__lockdep_no_validate__) + check = 1; + if (!subclass) class = lock->class_cache; /* diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index a4d7434..f2bbea9 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 -- 2.7.4