lockdep: Make held_lock->check and "int check" argument bool

The "int check" argument of lock_acquire() and held_lock->check are
misleading. This is actually a boolean: 2 means "true", everything
else is "false".

And there is no need to pass 1 or 0 to lock_acquire() depending on
CONFIG_PROVE_LOCKING, __lock_acquire() checks prove_locking at the
start and clears "check" if !CONFIG_PROVE_LOCKING.

Note: probably we can simply kill this member/arg. The only explicit
user of check => 0 is rcu_lock_acquire(), perhaps we can change it to
use lock_acquire(trylock =>, read => 2). __lockdep_no_validate means
check => 0 implicitly, but we can change validate_chain() to check
hlock->instance->key instead. Not to mention it would be nice to get
rid of lockdep_set_novalidate_class().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140120182006.GA26495@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/tty/tty_ldsem.c b/drivers/tty/tty_ldsem.c
index d8a55e87877f06f3141602e4f08cdcb668c465b0..0ffb0cbe28237239ffd093877a363c7957c8e328 100644 (file)
--- a/drivers/tty/tty_ldsem.c
+++ b/drivers/tty/tty_ldsem.c
@@ -39,17 +39,10 @@
                                lock_acquire(&(l)->dep_map, s, t, r, c, n, i)
 # define __rel(l, n, i)                                \
                                lock_release(&(l)->dep_map, n, i)
-# ifdef CONFIG_PROVE_LOCKING
-#  define lockdep_acquire(l, s, t, i)          __acq(l, s, t, 0, 2, NULL, i)
-#  define lockdep_acquire_nest(l, s, t, n, i)  __acq(l, s, t, 0, 2, n, i)
-#  define lockdep_acquire_read(l, s, t, i)     __acq(l, s, t, 1, 2, NULL, i)
-#  define lockdep_release(l, n, i)             __rel(l, n, i)
-# else
-#  define lockdep_acquire(l, s, t, i)          __acq(l, s, t, 0, 1, NULL, i)
-#  define lockdep_acquire_nest(l, s, t, n, i)  __acq(l, s, t, 0, 1, n, i)
-#  define lockdep_acquire_read(l, s, t, i)     __acq(l, s, t, 1, 1, NULL, i)
-#  define lockdep_release(l, n, i)             __rel(l, n, i)
-# endif
+#define lockdep_acquire(l, s, t, i)            __acq(l, s, t, 0, 1, NULL, i)
+#define lockdep_acquire_nest(l, s, t, n, i)    __acq(l, s, t, 0, 1, n, i)
+#define lockdep_acquire_read(l, s, t, i)       __acq(l, s, t, 1, 1, NULL, i)
+#define lockdep_release(l, n, i)               __rel(l, n, i)
 #else
 # define lockdep_acquire(l, s, t, i)           do { } while (0)
 # define lockdep_acquire_nest(l, s, t, n, i)   do { } while (0)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 92b1bfc5da6087850e43015ebdaf7d3de455f522..1626047c1f2633bd30bab7c027cbc90eb106d914 100644 (file)
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -252,9 +252,9 @@ struct held_lock {
        unsigned int trylock:1;                                         /* 16 bits */
 
        unsigned int read:2;        /* see lock_acquire() comment */
-       unsigned int check:2;       /* see lock_acquire() comment */
+       unsigned int check:1;       /* see lock_acquire() comment */
        unsigned int hardirqs_off:1;
-       unsigned int references:11;                                     /* 32 bits */
+       unsigned int references:12;                                     /* 32 bits */
 };
 
 /*
@@ -326,9 +326,8 @@ static inline int lockdep_match_key(struct lockdep_map *lock,
  *
  * Values for check:
  *
- *   0: disabled
- *   1: simple checks (freeing, held-at-exit-time, etc.)
- *   2: full validation
+ *   0: simple checks (freeing, held-at-exit-time, etc.)
+ *   1: full validation
  */
 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
                         int trylock, int read, int check,
@@ -479,15 +478,9 @@ static inline void print_irqtrace_events(struct task_struct *curr)
  * on the per lock-class debug mode:
  */
 
-#ifdef CONFIG_PROVE_LOCKING
- #define lock_acquire_exclusive(l, s, t, n, i)         lock_acquire(l, s, t, 0, 2, n, i)
- #define lock_acquire_shared(l, s, t, n, i)            lock_acquire(l, s, t, 1, 2, n, i)
- #define lock_acquire_shared_recursive(l, s, t, n, i)  lock_acquire(l, s, t, 2, 2, n, i)
-#else
- #define lock_acquire_exclusive(l, s, t, n, i)         lock_acquire(l, s, t, 0, 1, n, i)
- #define lock_acquire_shared(l, s, t, n, i)            lock_acquire(l, s, t, 1, 1, n, i)
- #define lock_acquire_shared_recursive(l, s, t, n, i)  lock_acquire(l, s, t, 2, 1, n, i)
-#endif
+#define lock_acquire_exclusive(l, s, t, n, i)          lock_acquire(l, s, t, 0, 1, n, i)
+#define lock_acquire_shared(l, s, t, n, i)             lock_acquire(l, s, t, 1, 1, n, i)
+#define lock_acquire_shared_recursive(l, s, t, n, i)   lock_acquire(l, s, t, 2, 1, n, i)
 
 #define spin_acquire(l, s, t, i)               lock_acquire_exclusive(l, s, t, NULL, i)
 #define spin_acquire_nest(l, s, t, n, i)       lock_acquire_exclusive(l, s, t, n, i)
@@ -518,13 +511,13 @@ static inline void print_irqtrace_events(struct task_struct *curr)
 # define might_lock(lock)                                              \
 do {                                                                   \
        typecheck(struct lockdep_map *, &(lock)->dep_map);              \
-       lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_);    \
+       lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_);    \
        lock_release(&(lock)->dep_map, 0, _THIS_IP_);                   \
 } while (0)
 # define might_lock_read(lock)                                                 \
 do {                                                                   \
        typecheck(struct lockdep_map *, &(lock)->dep_map);              \
-       lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_);    \
+       lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_);    \
        lock_release(&(lock)->dep_map, 0, _THIS_IP_);                   \
 } while (0)
 #else

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 72bf3a01a4ee67ac8908212c3de3897d383a2161..adff3c99dcaa41f8581607833baaa4398e3ed1a7 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -314,7 +314,7 @@ static inline bool rcu_lockdep_current_cpu_online(void)
 
 static inline void rcu_lock_acquire(struct lockdep_map *map)
 {
-       lock_acquire(map, 0, 0, 2, 1, NULL, _THIS_IP_);
+       lock_acquire(map, 0, 0, 2, 0, NULL, _THIS_IP_);
 }
 
 static inline void rcu_lock_release(struct lockdep_map *map)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index eb8a54783fa0f47bb9b51568ec9dfed3d51cc48d..8c85a0da5a383b5577c66dca9c5ed3ce2e42cdc8 100644 (file)
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2098,7 +2098,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
         * (If lookup_chain_cache() returns with 1 it acquires
         * graph_lock for us)
         */
-       if (!hlock->trylock && (hlock->check == 2) &&
+       if (!hlock->trylock && hlock->check &&
            lookup_chain_cache(curr, hlock, chain_key)) {
                /*
                 * Check whether last held lock:
@@ -3055,9 +3055,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
        int class_idx;
        u64 chain_key;
 
-       if (!prove_locking)
-               check = 1;
-
        if (unlikely(!debug_locks))
                return 0;
 
@@ -3069,8 +3066,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
        if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
                return 0;
 
-       if (lock->key == &__lockdep_no_validate__)
-               check = 1;
+       if (!prove_locking || lock->key == &__lockdep_no_validate__)
+               check = 0;
 
        if (subclass < NR_LOCKDEP_CACHING_CLASSES)
                class = lock->class_cache[subclass];
@@ -3138,7 +3135,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
        hlock->holdtime_stamp = lockstat_clock();
 #endif
 
-       if (check == 2 && !mark_irqflags(curr, hlock))
+       if (check && !mark_irqflags(curr, hlock))
                return 0;
 
        /* mark it as used: */