2 files changed, 90 insertions, 1 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 6c07f30fa9b7..296132c19a57 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -10,7 +10,7 @@ obj-y     = fork.o exec_domain.o panic.o printk.o \
             kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
             hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
             notifier.o ksysfs.o cred.o \
-            async.o range.o groups.o
+            async.o range.o groups.o lglock.o
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not trace debug files and internal ftrace files
diff --git a/kernel/lglock.c b/kernel/lglock.c
new file mode 100644
index 000000000000..6535a667a5a7
--- /dev/null
+++ b/kernel/lglock.c
@@ -0,0 +1,89 @@
+/* See include/linux/lglock.h for description */
+#include <linux/module.h>
+#include <linux/lglock.h>
+#include <linux/cpu.h>
+#include <linux/string.h>
+
+/*
+ * Note there is no uninit, so lglocks cannot be defined in
+ * modules (but it's fine to use them from there)
+ * Could be added though, just undo lg_lock_init
+ */
+
+void lg_lock_init(struct lglock *lg, char *name)
+{
+        LOCKDEP_INIT_MAP(&lg->lock_dep_map, name, &lg->lock_key, 0);
+}
+EXPORT_SYMBOL(lg_lock_init);
+
+void lg_local_lock(struct lglock *lg)
+{
+        arch_spinlock_t *lock;
+
+        preempt_disable();
+        rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
+        lock = this_cpu_ptr(lg->lock);
+        arch_spin_lock(lock);
+}
+EXPORT_SYMBOL(lg_local_lock);
+
+void lg_local_unlock(struct lglock *lg)
+{
+        arch_spinlock_t *lock;
+
+        rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+        lock = this_cpu_ptr(lg->lock);
+        arch_spin_unlock(lock);
+        preempt_enable();
+}
+EXPORT_SYMBOL(lg_local_unlock);
+
+void lg_local_lock_cpu(struct lglock *lg, int cpu)
+{
+        arch_spinlock_t *lock;
+
+        preempt_disable();
+        rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
+        lock = per_cpu_ptr(lg->lock, cpu);
+        arch_spin_lock(lock);
+}
+EXPORT_SYMBOL(lg_local_lock_cpu);
+
+void lg_local_unlock_cpu(struct lglock *lg, int cpu)
+{
+        arch_spinlock_t *lock;
+
+        rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+        lock = per_cpu_ptr(lg->lock, cpu);
+        arch_spin_unlock(lock);
+        preempt_enable();
+}
+EXPORT_SYMBOL(lg_local_unlock_cpu);
+
+void lg_global_lock(struct lglock *lg)
+{
+        int i;
+
+        preempt_disable();
+        rwlock_acquire(&lg->lock_dep_map, 0, 0, _RET_IP_);
+        for_each_possible_cpu(i) {
+                arch_spinlock_t *lock;
+                lock = per_cpu_ptr(lg->lock, i);
+                arch_spin_lock(lock);
+        }
+}
+EXPORT_SYMBOL(lg_global_lock);
+
+void lg_global_unlock(struct lglock *lg)
+{
+        int i;
+
+        rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+        for_each_possible_cpu(i) {
+                arch_spinlock_t *lock;
+                lock = per_cpu_ptr(lg->lock, i);
+                arch_spin_unlock(lock);
+        }
+        preempt_enable();
+}
+EXPORT_SYMBOL(lg_global_unlock);