KVM: Drop useless atomic test from timer function
[safe/jmp/linux-2.6] / kernel / lockdep.c
index 22ced8d..8bbeef9 100644 (file)
 #include <linux/utsname.h>
 #include <linux/hash.h>
 #include <linux/ftrace.h>
+#include <linux/stringify.h>
 
 #include <asm/sections.h>
 
 #include "lockdep_internals.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/lockdep.h>
+
 #ifdef CONFIG_PROVE_LOCKING
 int prove_locking = 1;
 module_param(prove_locking, int, 0644);
@@ -432,27 +436,17 @@ atomic_t nr_find_usage_forwards_checks;
 atomic_t nr_find_usage_forwards_recursions;
 atomic_t nr_find_usage_backwards_checks;
 atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr)         atomic_inc(ptr)
-# define debug_atomic_dec(ptr)         atomic_dec(ptr)
-# define debug_atomic_read(ptr)                atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr)         do { } while (0)
-# define debug_atomic_dec(ptr)         do { } while (0)
-# define debug_atomic_read(ptr)                0
 #endif
 
 /*
  * Locking printouts:
  */
 
-#define __STR(foo)     #foo
-#define STR(foo)       __STR(foo)
-
 #define __USAGE(__STATE)                                               \
-       [LOCK_USED_IN_##__STATE] = "IN-"STR(__STATE)"-W",               \
-       [LOCK_ENABLED_##__STATE] = STR(__STATE)"-ON-W",                 \
-       [LOCK_USED_IN_##__STATE##_READ] = "IN-"STR(__STATE)"-R",        \
-       [LOCK_ENABLED_##__STATE##_READ] = STR(__STATE)"-ON-R",
+       [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W",       \
+       [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W",         \
+       [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
+       [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
 
 static const char *usage_str[] =
 {
@@ -801,6 +795,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 
                printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
                printk("turning off the locking correctness validator.\n");
+               dump_stack();
                return NULL;
        }
        class = lock_classes + nr_lock_classes++;
@@ -864,6 +859,7 @@ static struct lock_list *alloc_list_entry(void)
 
                printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
                printk("turning off the locking correctness validator.\n");
+               dump_stack();
                return NULL;
        }
        return list_entries + nr_list_entries++;
@@ -1268,68 +1264,84 @@ check_usage(struct task_struct *curr, struct held_lock *prev,
                        bit_backwards, bit_forwards, irqclass);
 }
 
-static int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
-               struct held_lock *next)
+static const char *state_names[] = {
+#define LOCKDEP_STATE(__STATE) \
+       __stringify(__STATE),
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static const char *state_rnames[] = {
+#define LOCKDEP_STATE(__STATE) \
+       __stringify(__STATE)"-READ",
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline const char *state_name(enum lock_usage_bit bit)
 {
-       /*
-        * Prove that the new dependency does not connect a hardirq-safe
-        * lock with a hardirq-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
-        */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
-                                       LOCK_ENABLED_HARDIRQ, "hard"))
-               return 0;
+       return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
+}
 
+static int exclusive_bit(int new_bit)
+{
        /*
-        * Prove that the new dependency does not connect a hardirq-safe-read
-        * lock with a hardirq-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
+        * USED_IN
+        * USED_IN_READ
+        * ENABLED
+        * ENABLED_READ
+        *
+        * bit 0 - write/read
+        * bit 1 - used_in/enabled
+        * bit 2+  state
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
-                                       LOCK_ENABLED_HARDIRQ, "hard-read"))
-               return 0;
+
+       int state = new_bit & ~3;
+       int dir = new_bit & 2;
 
        /*
-        * Prove that the new dependency does not connect a softirq-safe
-        * lock with a softirq-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
+        * keep state, bit flip the direction and strip read.
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
-                                       LOCK_ENABLED_SOFTIRQ, "soft"))
-               return 0;
+       return state | (dir ^ 2);
+}
+
+static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
+                          struct held_lock *next, enum lock_usage_bit bit)
+{
        /*
-        * Prove that the new dependency does not connect a softirq-safe-read
-        * lock with a softirq-unsafe lock - to achieve this we search
+        * Prove that the new dependency does not connect a hardirq-safe
+        * lock with a hardirq-unsafe lock - to achieve this we search
         * the backwards-subgraph starting at <prev>, and the
         * forwards-subgraph starting at <next>:
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
-                                       LOCK_ENABLED_SOFTIRQ, "soft"))
+       if (!check_usage(curr, prev, next, bit,
+                          exclusive_bit(bit), state_name(bit)))
                return 0;
 
+       bit++; /* _READ */
+
        /*
-        * Prove that the new dependency does not connect a reclaim-fs-safe
-        * lock with a reclaim-fs-unsafe lock - to achieve this we search
+        * Prove that the new dependency does not connect a hardirq-safe-read
+        * lock with a hardirq-unsafe lock - to achieve this we search
         * the backwards-subgraph starting at <prev>, and the
         * forwards-subgraph starting at <next>:
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS,
-                                       LOCK_ENABLED_RECLAIM_FS, "reclaim-fs"))
+       if (!check_usage(curr, prev, next, bit,
+                          exclusive_bit(bit), state_name(bit)))
                return 0;
 
-       /*
-        * Prove that the new dependency does not connect a reclaim-fs-safe-read
-        * lock with a reclaim-fs-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
-        */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS_READ,
-                                       LOCK_ENABLED_RECLAIM_FS, "reclaim-fs-read"))
+       return 1;
+}
+
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+               struct held_lock *next)
+{
+#define LOCKDEP_STATE(__STATE)                                         \
+       if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
                return 0;
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
 
        return 1;
 }
@@ -1674,6 +1686,7 @@ cache_hit:
 
                printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
                printk("turning off the locking correctness validator.\n");
+               dump_stack();
                return 0;
        }
        chain = lock_chains + nr_lock_chains++;
@@ -1886,9 +1899,9 @@ print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
                curr->comm, task_pid_nr(curr));
        print_lock(this);
        if (forwards)
-               printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
+               printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
        else
-               printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
+               printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
        print_lock_name(other);
        printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
 
@@ -1984,30 +1997,6 @@ static int RECLAIM_FS_verbose(struct lock_class *class)
 
 #define STRICT_READ_CHECKS     1
 
-static const char *state_names[] = {
-#define LOCKDEP_STATE(__STATE) \
-       STR(__STATE),
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline const char *state_name(enum lock_usage_bit bit)
-{
-       return state_names[bit >> 2];
-}
-
-static const char *state_rnames[] = {
-#define LOCKDEP_STATE(__STATE) \
-       STR(__STATE)"-READ",
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline const char *state_rname(enum lock_usage_bit bit)
-{
-       return state_rnames[bit >> 2];
-}
-
 static int (*state_verbose_f[])(struct lock_class *class) = {
 #define LOCKDEP_STATE(__STATE) \
        __STATE##_verbose,
@@ -2021,37 +2010,13 @@ static inline int state_verbose(enum lock_usage_bit bit,
        return state_verbose_f[bit >> 2](class);
 }
 
-static int exclusive_bit(int new_bit)
-{
-       /*
-        * USED_IN
-        * USED_IN_READ
-        * ENABLED
-        * ENABLED_READ
-        *
-        * bit 0 - write/read
-        * bit 1 - used_in/enabled
-        * bit 2+  state
-        */
-
-       int state = new_bit & ~3;
-       int dir = new_bit & 2;
-
-       /*
-        * keep state, bit flip the direction and strip read.
-        */
-       return state | (dir ^ 2);
-}
-
 typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
                             enum lock_usage_bit bit, const char *name);
 
 static int
-mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
+mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+               enum lock_usage_bit new_bit)
 {
-       const char *name = state_name(new_bit);
-       const char *rname = state_rname(new_bit);
-
        int excl_bit = exclusive_bit(new_bit);
        int read = new_bit & 1;
        int dir = new_bit & 2;
@@ -2078,7 +2043,7 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
         * states.
         */
        if ((!read || !dir || STRICT_READ_CHECKS) &&
-                       !usage(curr, this, excl_bit, name))
+                       !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
                return 0;
 
        /*
@@ -2089,7 +2054,8 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
                        return 0;
 
                if (STRICT_READ_CHECKS &&
-                               !usage(curr, this, excl_bit + 1, rname))
+                       !usage(curr, this, excl_bit + 1,
+                               state_name(new_bit + 1)))
                        return 0;
        }
 
@@ -2294,7 +2260,7 @@ void trace_softirqs_off(unsigned long ip)
                debug_atomic_inc(&redundant_softirqs_off);
 }
 
-void lockdep_trace_alloc(gfp_t gfp_mask)
+static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
 {
        struct task_struct *curr = current;
 
@@ -2313,12 +2279,29 @@ void lockdep_trace_alloc(gfp_t gfp_mask)
        if (!(gfp_mask & __GFP_FS))
                return;
 
-       if (DEBUG_LOCKS_WARN_ON(irqs_disabled()))
+       if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
                return;
 
        mark_held_locks(curr, RECLAIM_FS);
 }
 
+static void check_flags(unsigned long flags);
+
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+       unsigned long flags;
+
+       if (unlikely(current->lockdep_recursion))
+               return;
+
+       raw_local_irq_save(flags);
+       check_flags(flags);
+       current->lockdep_recursion = 1;
+       __lockdep_trace_alloc(gfp_mask, flags);
+       current->lockdep_recursion = 0;
+       raw_local_irq_restore(flags);
+}
+
 static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
 {
        /*
@@ -2430,6 +2413,10 @@ static inline int separate_irq_context(struct task_struct *curr,
        return 0;
 }
 
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+}
+
 #endif
 
 /*
@@ -2505,13 +2492,20 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 void lockdep_init_map(struct lockdep_map *lock, const char *name,
                      struct lock_class_key *key, int subclass)
 {
-       if (unlikely(!debug_locks))
+       lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+       lock->cpu = raw_smp_processor_id();
+#endif
+
+       if (DEBUG_LOCKS_WARN_ON(!name)) {
+               lock->name = "NULL";
                return;
+       }
+
+       lock->name = name;
 
        if (DEBUG_LOCKS_WARN_ON(!key))
                return;
-       if (DEBUG_LOCKS_WARN_ON(!name))
-               return;
        /*
         * Sanity check, the lock-class key must be persistent:
         */
@@ -2520,12 +2514,11 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name,
                DEBUG_LOCKS_WARN_ON(1);
                return;
        }
-       lock->name = name;
        lock->key = key;
-       lock->class_cache = NULL;
-#ifdef CONFIG_LOCK_STAT
-       lock->cpu = raw_smp_processor_id();
-#endif
+
+       if (unlikely(!debug_locks))
+               return;
+
        if (subclass)
                register_lock_class(lock, subclass, 1);
 }
@@ -2559,6 +2552,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
                debug_locks_off();
                printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
                printk("turning off the locking correctness validator.\n");
+               dump_stack();
                return 0;
        }
 
@@ -2655,6 +2649,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
                debug_locks_off();
                printk("BUG: MAX_LOCK_DEPTH too low!\n");
                printk("turning off the locking correctness validator.\n");
+               dump_stack();
                return 0;
        }
 
@@ -2952,6 +2947,8 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 {
        unsigned long flags;
 
+       trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
+
        if (unlikely(current->lockdep_recursion))
                return;
 
@@ -2971,6 +2968,8 @@ void lock_release(struct lockdep_map *lock, int nested,
 {
        unsigned long flags;
 
+       trace_lock_release(lock, nested, ip);
+
        if (unlikely(current->lockdep_recursion))
                return;
 
@@ -3104,6 +3103,8 @@ found_it:
                hlock->holdtime_stamp = now;
        }
 
+       trace_lock_acquired(lock, ip, waittime);
+
        stats = get_lock_stats(hlock_class(hlock));
        if (waittime) {
                if (hlock->read)
@@ -3123,6 +3124,8 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip)
 {
        unsigned long flags;
 
+       trace_lock_contended(lock, ip);
+
        if (unlikely(!lock_stat))
                return;