Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / include / linux / lglock.h

diff --git a/kernel/include/linux/lglock.h b/kernel/include/linux/lglock.h
new file mode 100644 (file)
index 0000000..9603a15
--- /dev/null
+++ b/kernel/include/linux/lglock.h
@@ -0,0 +1,99 @@
+/*
+ * Specialised local-global spinlock. Can only be declared as global variables
+ * to avoid overhead and keep things simple (and we don't want to start using
+ * these inside dynamically allocated structures).
+ *
+ * "local/global locks" (lglocks) can be used to:
+ *
+ * - Provide fast exclusive access to per-CPU data, with exclusive access to
+ *   another CPU's data allowed but possibly subject to contention, and to
+ *   provide very slow exclusive access to all per-CPU data.
+ * - Or to provide very fast and scalable read serialisation, and to provide
+ *   very slow exclusive serialisation of data (not necessarily per-CPU data).
+ *
+ * Brlocks are also implemented as a short-hand notation for the latter use
+ * case.
+ *
+ * Copyright 2009, 2010, Nick Piggin, Novell Inc.
+ */
+#ifndef __LINUX_LGLOCK_H
+#define __LINUX_LGLOCK_H
+
+#include <linux/spinlock.h>
+#include <linux/lockdep.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+
+#ifdef CONFIG_SMP
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define LOCKDEP_INIT_MAP lockdep_init_map
+#else
+#define LOCKDEP_INIT_MAP(a, b, c, d)
+#endif
+
+struct lglock {
+#ifndef CONFIG_PREEMPT_RT_FULL
+       arch_spinlock_t __percpu *lock;
+#else
+       struct rt_mutex __percpu *lock;
+#endif
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+       struct lock_class_key lock_key;
+       struct lockdep_map    lock_dep_map;
+#endif
+};
+
+#ifndef CONFIG_PREEMPT_RT_FULL
+# define DEFINE_LGLOCK(name)                                           \
+       static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock)           \
+       = __ARCH_SPIN_LOCK_UNLOCKED;                                    \
+       struct lglock name = { .lock = &name ## _lock }
+
+# define DEFINE_STATIC_LGLOCK(name)                                    \
+       static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock)           \
+       = __ARCH_SPIN_LOCK_UNLOCKED;                                    \
+       static struct lglock name = { .lock = &name ## _lock }
+#else
+
+# define DEFINE_LGLOCK(name)                                           \
+       static DEFINE_PER_CPU(struct rt_mutex, name ## _lock)           \
+       = __RT_MUTEX_INITIALIZER( name ## _lock);                       \
+       struct lglock name = { .lock = &name ## _lock }
+
+# define DEFINE_STATIC_LGLOCK(name)                                    \
+       static DEFINE_PER_CPU(struct rt_mutex, name ## _lock)           \
+       = __RT_MUTEX_INITIALIZER( name ## _lock);                       \
+       static struct lglock name = { .lock = &name ## _lock }
+#endif
+
+void lg_lock_init(struct lglock *lg, char *name);
+void lg_local_lock(struct lglock *lg);
+void lg_local_unlock(struct lglock *lg);
+void lg_local_lock_cpu(struct lglock *lg, int cpu);
+void lg_local_unlock_cpu(struct lglock *lg, int cpu);
+void lg_global_lock(struct lglock *lg);
+void lg_global_unlock(struct lglock *lg);
+
+#ifndef CONFIG_PREEMPT_RT_FULL
+#define lg_global_trylock_relax(name)  lg_global_lock(name)
+#else
+void lg_global_trylock_relax(struct lglock *lg);
+#endif
+
+#else
+/* When !CONFIG_SMP, map lglock to spinlock */
+#define lglock spinlock
+#define DEFINE_LGLOCK(name) DEFINE_SPINLOCK(name)
+#define DEFINE_STATIC_LGLOCK(name) static DEFINE_SPINLOCK(name)
+#define lg_lock_init(lg, name) spin_lock_init(lg)
+#define lg_local_lock spin_lock
+#define lg_local_unlock spin_unlock
+#define lg_local_lock_cpu(lg, cpu) spin_lock(lg)
+#define lg_local_unlock_cpu(lg, cpu) spin_unlock(lg)
+#define lg_global_lock spin_lock
+#define lg_global_unlock spin_unlock
+#endif
+
+#endif