[PATCH] mutex subsystem, debugging code

mutex implementation - add debugging code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>

1 files changed, 134 insertions, 0 deletions

diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h
new file mode 100644
index 000000000000..fd384050acb1
--- /dev/null
+++ b/kernel/mutex-debug.h
@@ -0,0 +1,134 @@
+/*
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * This file contains mutex debugging related internal declarations,
+ * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case.
+ * More details are in kernel/mutex-debug.c.
+ */
+
+extern spinlock_t debug_mutex_lock;
+extern struct list_head debug_mutex_held_locks;
+extern int debug_mutex_on;
+
+/*
+ * In the debug case we carry the caller's instruction pointer into
+ * other functions, but we dont want the function argument overhead
+ * in the nondebug case - hence these macros:
+ */
+#define __IP_DECL__             , unsigned long ip
+#define __IP__                  , ip
+#define __RET_IP__              , (unsigned long)__builtin_return_address(0)
+
+/*
+ * This must be called with lock->wait_lock held.
+ */
+extern void debug_mutex_set_owner(struct mutex *lock,
+                                  struct thread_info *new_owner __IP_DECL__);
+
+static inline void debug_mutex_clear_owner(struct mutex *lock)
+{
+        lock->owner = NULL;
+}
+
+extern void debug_mutex_init_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_wake_waiter(struct mutex *lock,
+                                    struct mutex_waiter *waiter);
+extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_add_waiter(struct mutex *lock,
+                                   struct mutex_waiter *waiter,
+                                   struct thread_info *ti __IP_DECL__);
+extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+                                struct thread_info *ti);
+extern void debug_mutex_unlock(struct mutex *lock);
+extern void debug_mutex_init(struct mutex *lock, const char *name);
+
+#define debug_spin_lock(lock)                           \
+        do {                                            \
+                local_irq_disable();                    \
+                if (debug_mutex_on)                     \
+                        spin_lock(lock);                \
+        } while (0)
+
+#define debug_spin_unlock(lock)                         \
+        do {                                            \
+                if (debug_mutex_on)                     \
+                        spin_unlock(lock);              \
+                local_irq_enable();                     \
+                preempt_check_resched();                \
+        } while (0)
+
+#define debug_spin_lock_save(lock, flags)               \
+        do {                                            \
+                local_irq_save(flags);                  \
+                if (debug_mutex_on)                     \
+                        spin_lock(lock);                \
+        } while (0)
+
+#define debug_spin_lock_restore(lock, flags)            \
+        do {                                            \
+                if (debug_mutex_on)                     \
+                        spin_unlock(lock);              \
+                local_irq_restore(flags);               \
+                preempt_check_resched();                \
+        } while (0)
+
+#define spin_lock_mutex(lock)                           \
+        do {                                            \
+                struct mutex *l = container_of(lock, struct mutex, wait_lock); \
+                                                        \
+                DEBUG_WARN_ON(in_interrupt());          \
+                debug_spin_lock(&debug_mutex_lock);     \
+                spin_lock(lock);                        \
+                DEBUG_WARN_ON(l->magic != l);           \
+        } while (0)
+
+#define spin_unlock_mutex(lock)                         \
+        do {                                            \
+                spin_unlock(lock);                      \
+                debug_spin_unlock(&debug_mutex_lock);   \
+        } while (0)
+
+#define DEBUG_OFF()                                     \
+do {                                                    \
+        if (debug_mutex_on) {                           \
+                debug_mutex_on = 0;                     \
+                console_verbose();                      \
+                if (spin_is_locked(&debug_mutex_lock))  \
+                        spin_unlock(&debug_mutex_lock); \
+        }                                               \
+} while (0)
+
+#define DEBUG_BUG()                                     \
+do {                                                    \
+        if (debug_mutex_on) {                           \
+                DEBUG_OFF();                            \
+                BUG();                                  \
+        }                                               \
+} while (0)
+
+#define DEBUG_WARN_ON(c)                                \
+do {                                                    \
+        if (unlikely(c && debug_mutex_on)) {            \
+                DEBUG_OFF();                            \
+                WARN_ON(1);                             \
+        }                                               \
+} while (0)
+
+# define DEBUG_BUG_ON(c)                                \
+do {                                                    \
+        if (unlikely(c))                                \
+                DEBUG_BUG();                            \
+} while (0)
+
+#ifdef CONFIG_SMP
+# define SMP_DEBUG_WARN_ON(c)                   DEBUG_WARN_ON(c)
+# define SMP_DEBUG_BUG_ON(c)                    DEBUG_BUG_ON(c)
+#else
+# define SMP_DEBUG_WARN_ON(c)                   do { } while (0)
+# define SMP_DEBUG_BUG_ON(c)                    do { } while (0)
+#endif
+