kernel/locking/lglock.c

   1 /* See include/linux/lglock.h for description */
   2 #include <linux/module.h>
   3 #include <linux/lglock.h>
   4 #include <linux/cpu.h>
   5 #include <linux/string.h>
   6
   7 /*
   8  * Note there is no uninit, so lglocks cannot be defined in
   9  * modules (but it's fine to use them from there)
  10  * Could be added though, just undo lg_lock_init
  11  */
  12
  13 void lg_lock_init(struct lglock *lg, char *name)
  14 {
  15         LOCKDEP_INIT_MAP(&lg->lock_dep_map, name, &lg->lock_key, 0);
  16 }
  17 EXPORT_SYMBOL(lg_lock_init);
  18
  19 void lg_local_lock(struct lglock *lg)
  20 {
  21         arch_spinlock_t *lock;
  22
  23         preempt_disable();
  24         lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
  25         lock = this_cpu_ptr(lg->lock);
  26         arch_spin_lock(lock);
  27 }
  28 EXPORT_SYMBOL(lg_local_lock);
  29
  30 void lg_local_unlock(struct lglock *lg)
  31 {
  32         arch_spinlock_t *lock;
  33
  34         lock_release(&lg->lock_dep_map, 1, _RET_IP_);
  35         lock = this_cpu_ptr(lg->lock);
  36         arch_spin_unlock(lock);
  37         preempt_enable();
  38 }
  39 EXPORT_SYMBOL(lg_local_unlock);
  40
  41 void lg_local_lock_cpu(struct lglock *lg, int cpu)
  42 {
  43         arch_spinlock_t *lock;
  44
  45         preempt_disable();
  46         lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
  47         lock = per_cpu_ptr(lg->lock, cpu);
  48         arch_spin_lock(lock);
  49 }
  50 EXPORT_SYMBOL(lg_local_lock_cpu);
  51
  52 void lg_local_unlock_cpu(struct lglock *lg, int cpu)
  53 {
  54         arch_spinlock_t *lock;
  55
  56         lock_release(&lg->lock_dep_map, 1, _RET_IP_);
  57         lock = per_cpu_ptr(lg->lock, cpu);
  58         arch_spin_unlock(lock);
  59         preempt_enable();
  60 }
  61 EXPORT_SYMBOL(lg_local_unlock_cpu);
  62
  63 void lg_double_lock(struct lglock *lg, int cpu1, int cpu2)
  64 {
  65         BUG_ON(cpu1 == cpu2);
  66
  67         /* lock in cpu order, just like lg_global_lock */
  68         if (cpu2 < cpu1)
  69                 swap(cpu1, cpu2);
  70
  71         preempt_disable();
  72         lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
  73         arch_spin_lock(per_cpu_ptr(lg->lock, cpu1));
  74         arch_spin_lock(per_cpu_ptr(lg->lock, cpu2));
  75 }
  76
  77 void lg_double_unlock(struct lglock *lg, int cpu1, int cpu2)
  78 {
  79         lock_release(&lg->lock_dep_map, 1, _RET_IP_);
  80         arch_spin_unlock(per_cpu_ptr(lg->lock, cpu1));
  81         arch_spin_unlock(per_cpu_ptr(lg->lock, cpu2));
  82         preempt_enable();
  83 }
  84
  85 void lg_global_lock(struct lglock *lg)
  86 {
  87         int i;
  88
  89         preempt_disable();
  90         lock_acquire_exclusive(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
  91         for_each_possible_cpu(i) {
  92                 arch_spinlock_t *lock;
  93                 lock = per_cpu_ptr(lg->lock, i);
  94                 arch_spin_lock(lock);
  95         }
  96 }
  97 EXPORT_SYMBOL(lg_global_lock);
  98
  99 void lg_global_unlock(struct lglock *lg)
 100 {
 101         int i;
 102
 103         lock_release(&lg->lock_dep_map, 1, _RET_IP_);
 104         for_each_possible_cpu(i) {
 105                 arch_spinlock_t *lock;
 106                 lock = per_cpu_ptr(lg->lock, i);
 107                 arch_spin_unlock(lock);
 108         }
 109         preempt_enable();
 110 }
 111 EXPORT_SYMBOL(lg_global_unlock);