[PATCH 03/14] mm: introduce mm locking wrappers

[Davidlohr Bueso]

This patch adds the necessary wrappers to encapsulate mmap_sem
locking and will enable any future changes to be a lot more
confined to here. In addition, future users will incrementally
be added in the next patches. mm_[read/write]_[un]lock() naming
is used.

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
 include/linux/mm.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0e8834ac32b7..780b6097ee47 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -12,6 +12,7 @@
 #include <linux/list.h>
 #include <linux/mmzone.h>
 #include <linux/rbtree.h>
+#include <linux/range_lock.h>
 #include <linux/atomic.h>
 #include <linux/debug_locks.h>
 #include <linux/mm_types.h>
@@ -2880,5 +2881,80 @@ void __init setup_nr_node_ids(void);
 static inline void setup_nr_node_ids(void) {}
 #endif
 
+/*
+ * Address space locking wrappers.
+ */
+static inline bool mm_is_locked(struct mm_struct *mm,
+				struct range_lock *mmrange)
+{
+	return rwsem_is_locked(&mm->mmap_sem);
+}
+
+/* Reader wrappers */
+static inline int mm_read_trylock(struct mm_struct *mm,
+				  struct range_lock *mmrange)
+{
+	return down_read_trylock(&mm->mmap_sem);
+}
+
+static inline void mm_read_lock(struct mm_struct *mm,
+				struct range_lock *mmrange)
+{
+	down_read(&mm->mmap_sem);
+}
+
+static inline void mm_read_lock_nested(struct mm_struct *mm,
+				       struct range_lock *mmrange, int subclass)
+{
+	down_read_nested(&mm->mmap_sem, subclass);
+}
+
+static inline void mm_read_unlock(struct mm_struct *mm,
+				  struct range_lock *mmrange)
+{
+	up_read(&mm->mmap_sem);
+}
+
+/* Writer wrappers */
+static inline int mm_write_trylock(struct mm_struct *mm,
+				   struct range_lock *mmrange)
+{
+	return down_write_trylock(&mm->mmap_sem);
+}
+
+static inline void mm_write_lock(struct mm_struct *mm,
+				 struct range_lock *mmrange)
+{
+	down_write(&mm->mmap_sem);
+}
+
+static inline int mm_write_lock_killable(struct mm_struct *mm,
+					 struct range_lock *mmrange)
+{
+	return down_write_killable(&mm->mmap_sem);
+}
+
+static inline void mm_downgrade_write(struct mm_struct *mm,
+				      struct range_lock *mmrange)
+{
+	downgrade_write(&mm->mmap_sem);
+}
+
+static inline void mm_write_unlock(struct mm_struct *mm,
+				   struct range_lock *mmrange)
+{
+	up_write(&mm->mmap_sem);
+}
+
+static inline void mm_write_lock_nested(struct mm_struct *mm,
+					struct range_lock *mmrange,
+					int subclass)
+{
+	down_write_nested(&mm->mmap_sem, subclass);
+}
+
+#define mm_write_nest_lock(mm, range, nest_lock)		\
+	down_write_nest_lock(&(mm)->mmap_sem, nest_lock)
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */
-- 
2.16.4