lglock: remove online variants of lock

Optimizing the slow paths adds a lot of complexity.  If you need to
grab every lock often, you have other problems.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/include/linux/lglock.h b/include/linux/lglock.h
index 87f402ccec55567330943ab774ffb12ae21c7da8..0fdd821e77b702e224dd7f23e9b5072dad2a12b7 100644 (file)
--- a/include/linux/lglock.h
+++ b/include/linux/lglock.h
@@ -28,8 +28,8 @@
 #define br_lock_init(name)     name##_lock_init()
 #define br_read_lock(name)     name##_local_lock()
 #define br_read_unlock(name)   name##_local_unlock()
-#define br_write_lock(name)    name##_global_lock_online()
-#define br_write_unlock(name)  name##_global_unlock_online()
+#define br_write_lock(name)    name##_global_lock()
+#define br_write_unlock(name)  name##_global_unlock()
 
 #define DECLARE_BRLOCK(name)   DECLARE_LGLOCK(name)
 #define DEFINE_BRLOCK(name)    DEFINE_LGLOCK(name)
@@ -42,8 +42,6 @@
 #define lg_local_unlock_cpu(name, cpu) name##_local_unlock_cpu(cpu)
 #define lg_global_lock(name)   name##_global_lock()
 #define lg_global_unlock(name) name##_global_unlock()
-#define lg_global_lock_online(name) name##_global_lock_online()
-#define lg_global_unlock_online(name) name##_global_unlock_online()
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define LOCKDEP_INIT_MAP lockdep_init_map
@@ -68,36 +66,13 @@
  extern void name##_local_unlock_cpu(int cpu);                         \
  extern void name##_global_lock(void);                                 \
  extern void name##_global_unlock(void);                               \
- extern void name##_global_lock_online(void);                          \
- extern void name##_global_unlock_online(void);                                \
 
 #define DEFINE_LGLOCK(name)                                            \
                                                                        \
  DEFINE_SPINLOCK(name##_cpu_lock);                                     \
- cpumask_t name##_cpus __read_mostly;                                  \
  DEFINE_PER_CPU(arch_spinlock_t, name##_lock);                         \
  DEFINE_LGLOCK_LOCKDEP(name);                                          \
                                                                        \
- static int                                                            \
- name##_lg_cpu_callback(struct notifier_block *nb,                     \
-                               unsigned long action, void *hcpu)       \
- {                                                                     \
-       switch (action & ~CPU_TASKS_FROZEN) {                           \
-       case CPU_UP_PREPARE:                                            \
-               spin_lock(&name##_cpu_lock);                            \
-               cpu_set((unsigned long)hcpu, name##_cpus);              \
-               spin_unlock(&name##_cpu_lock);                          \
-               break;                                                  \
-       case CPU_UP_CANCELED: case CPU_DEAD:                            \
-               spin_lock(&name##_cpu_lock);                            \
-               cpu_clear((unsigned long)hcpu, name##_cpus);            \
-               spin_unlock(&name##_cpu_lock);                          \
-       }                                                               \
-       return NOTIFY_OK;                                               \
- }                                                                     \
- static struct notifier_block name##_lg_cpu_notifier = {               \
-       .notifier_call = name##_lg_cpu_callback,                        \
- };                                                                    \
  void name##_lock_init(void) {                                         \
        int i;                                                          \
        LOCKDEP_INIT_MAP(&name##_lock_dep_map, #name, &name##_lock_key, 0); \
@@ -106,11 +81,6 @@
                lock = &per_cpu(name##_lock, i);                        \
                *lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;     \
        }                                                               \
-       register_hotcpu_notifier(&name##_lg_cpu_notifier);              \
-       get_online_cpus();                                              \
-       for_each_online_cpu(i)                                          \
-               cpu_set(i, name##_cpus);                                \
-       put_online_cpus();                                              \
  }                                                                     \
  EXPORT_SYMBOL(name##_lock_init);                                      \
                                                                        \
@@ -150,30 +120,6 @@
  }                                                                     \
  EXPORT_SYMBOL(name##_local_unlock_cpu);                               \
                                                                        \
- void name##_global_lock_online(void) {                                        \
-       int i;                                                          \
-       spin_lock(&name##_cpu_lock);                                    \
-       rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_);           \
-       for_each_cpu(i, &name##_cpus) {                                 \
-               arch_spinlock_t *lock;                                  \
-               lock = &per_cpu(name##_lock, i);                        \
-               arch_spin_lock(lock);                                   \
-       }                                                               \
- }                                                                     \
- EXPORT_SYMBOL(name##_global_lock_online);                             \
-                                                                       \
- void name##_global_unlock_online(void) {                              \
-       int i;                                                          \
-       rwlock_release(&name##_lock_dep_map, 1, _RET_IP_);              \
-       for_each_cpu(i, &name##_cpus) {                                 \
-               arch_spinlock_t *lock;                                  \
-               lock = &per_cpu(name##_lock, i);                        \
-               arch_spin_unlock(lock);                                 \
-       }                                                               \
-       spin_unlock(&name##_cpu_lock);                                  \
- }                                                                     \
- EXPORT_SYMBOL(name##_global_unlock_online);                           \
-                                                                       \
  void name##_global_lock(void) {                                       \
        int i;                                                          \
        preempt_disable();                                              \