#define _LINUX_SRCU_H
#include <linux/mutex.h>
+#include <linux/rcupdate.h>
struct srcu_struct_array {
int c[2];
__init_srcu_struct((sp), #sp, &__srcu_key); \
})
-# define srcu_read_acquire(sp) \
- lock_acquire(&(sp)->dep_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define srcu_read_release(sp) \
- lock_release(&(sp)->dep_map, 1, _THIS_IP_)
-
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
int init_srcu_struct(struct srcu_struct *sp);
-# define srcu_read_acquire(sp) do { } while (0)
-# define srcu_read_release(sp) do { } while (0)
-
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
void cleanup_srcu_struct(struct srcu_struct *sp);
* read-side critical section. In absence of CONFIG_DEBUG_LOCK_ALLOC,
* this assumes we are in an SRCU read-side critical section unless it can
* prove otherwise.
+ *
+ * Note that if the CPU is in an extended quiescent state, for example,
+ * if the CPU is in dyntick-idle mode, then rcu_read_lock_held() returns
+ * false even if the CPU did an rcu_read_lock(). The reason for this is
+ * that RCU ignores CPUs that are in extended quiescent states, so such
+ * a CPU is effectively never in an RCU read-side critical section
+ * regardless of what RCU primitives it invokes. This state of affairs
+ * is required -- RCU would otherwise need to periodically wake up
+ * dyntick-idle CPUs, which would defeat the whole purpose of dyntick-idle
+ * mode.
*/
static inline int srcu_read_lock_held(struct srcu_struct *sp)
{
if (debug_locks)
return lock_is_held(&sp->dep_map);
+ if (rcu_check_extended_qs())
+ return 0;
return 1;
}
{
int retval = __srcu_read_lock(sp);
- srcu_read_acquire(sp);
+ rcu_lock_acquire(&(sp)->dep_map);
return retval;
}
static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
__releases(sp)
{
- srcu_read_release(sp);
+ rcu_lock_release(&(sp)->dep_map);
__srcu_read_unlock(sp, idx);
}