brlocks/lglocks: turn into functions

lglocks and brlocks are currently generated with some complicated macros
in lglock.h.  But there's no reason to not just use common utility
functions and put all the data into a common data structure.

Since there are at least two users it makes sense to share this code in a
library.  This is also easier maintainable than a macro forest.

This will also make it later possible to dynamically allocate lglocks and
also use them in modules (this would both still need some additional, but
now straightforward, code)

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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);