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-rw-r--r--include/linux/srcu.h95
1 files changed, 93 insertions, 2 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 4765d97..3084f80 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -35,6 +35,9 @@ struct srcu_struct {
int completed;
struct srcu_struct_array *per_cpu_ref;
struct mutex mutex;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lockdep_map dep_map;
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
};
#ifndef CONFIG_PREEMPT
@@ -43,12 +46,100 @@ struct srcu_struct {
#define srcu_barrier()
#endif /* #else #ifndef CONFIG_PREEMPT */
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+int __init_srcu_struct(struct srcu_struct *sp, const char *name,
+ struct lock_class_key *key);
+
+#define init_srcu_struct(sp) \
+({ \
+ static struct lock_class_key __srcu_key; \
+ \
+ __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);
-int srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
-void srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);
+int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
+void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);
void synchronize_srcu(struct srcu_struct *sp);
void synchronize_srcu_expedited(struct srcu_struct *sp);
long srcu_batches_completed(struct srcu_struct *sp);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+/**
+ * srcu_read_lock_held - might we be in SRCU read-side critical section?
+ *
+ * If CONFIG_PROVE_LOCKING is selected and enabled, returns nonzero iff in
+ * an SRCU read-side critical section. In absence of CONFIG_PROVE_LOCKING,
+ * this assumes we are in an SRCU read-side critical section unless it can
+ * prove otherwise.
+ */
+static inline int srcu_read_lock_held(struct srcu_struct *sp)
+{
+ if (debug_locks)
+ return lock_is_held(&sp->dep_map);
+ return 1;
+}
+
+#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+static inline int srcu_read_lock_held(struct srcu_struct *sp)
+{
+ return 1;
+}
+
+#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+/**
+ * srcu_dereference - fetch SRCU-protected pointer with checking
+ *
+ * Makes rcu_dereference_check() do the dirty work.
+ */
+#define srcu_dereference(p, sp) \
+ rcu_dereference_check(p, srcu_read_lock_held(sp))
+
+/**
+ * srcu_read_lock - register a new reader for an SRCU-protected structure.
+ * @sp: srcu_struct in which to register the new reader.
+ *
+ * Enter an SRCU read-side critical section. Note that SRCU read-side
+ * critical sections may be nested.
+ */
+static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
+{
+ int retval = __srcu_read_lock(sp);
+
+ srcu_read_acquire(sp);
+ return retval;
+}
+
+/**
+ * srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
+ * @sp: srcu_struct in which to unregister the old reader.
+ * @idx: return value from corresponding srcu_read_lock().
+ *
+ * Exit an SRCU read-side critical section.
+ */
+static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
+ __releases(sp)
+{
+ srcu_read_release(sp);
+ __srcu_read_unlock(sp, idx);
+}
+
#endif
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