[PATCH v4 1/4] xfs: Refactor xfs_isilocked()

[Pavel Reichl <preichl@xxxxxxxxxx>]

Refactor xfs_isilocked() to use newly introduced __xfs_rwsem_islocked().
__xfs_rwsem_islocked() is a helper function which encapsulates checking
state of rw_semaphores hold by inode.

Signed-off-by: Pavel Reichl <preichl@xxxxxxxxxx>
Suggested-by: Dave Chinner <dchinner@xxxxxxxxxx>
Suggested-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
Changelog from V3:
Added ASSERTS() to isilocked() to make sure that only flags for a single
type of lock are passed 


 fs/xfs/xfs_inode.c | 51 ++++++++++++++++++++++++++++++++++------------
 fs/xfs/xfs_inode.h |  2 +-
 2 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index c5077e6326c7..cfefa7543b37 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -345,32 +345,57 @@ xfs_ilock_demote(
 }
 
 #if defined(DEBUG) || defined(XFS_WARN)
-int
+static inline bool
+__xfs_rwsem_islocked(
+	struct rw_semaphore	*rwsem,
+	bool			shared,
+	bool			excl)
+{
+	bool locked = false;
+
+	if (!rwsem_is_locked(rwsem))
+		return false;
+
+	if (!debug_locks)
+		return true;
+
+	if (shared)
+		locked = lockdep_is_held_type(rwsem, 0);
+
+	if (excl)
+		locked |= lockdep_is_held_type(rwsem, 1);
+
+	return locked;
+}
+
+bool
 xfs_isilocked(
-	xfs_inode_t		*ip,
+	struct xfs_inode	*ip,
 	uint			lock_flags)
 {
 	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
-		if (!(lock_flags & XFS_ILOCK_SHARED))
-			return !!ip->i_lock.mr_writer;
-		return rwsem_is_locked(&ip->i_lock.mr_lock);
+		ASSERT(!(lock_flags & ~(XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)));
+		return __xfs_rwsem_islocked(&ip->i_lock.mr_lock,
+				(lock_flags & XFS_ILOCK_SHARED),
+				(lock_flags & XFS_ILOCK_EXCL));
 	}
 
 	if (lock_flags & (XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)) {
-		if (!(lock_flags & XFS_MMAPLOCK_SHARED))
-			return !!ip->i_mmaplock.mr_writer;
-		return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
+		ASSERT(!(lock_flags & ~(XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)));
+		return __xfs_rwsem_islocked(&ip->i_mmaplock.mr_lock,
+				(lock_flags & XFS_MMAPLOCK_SHARED),
+				(lock_flags & XFS_MMAPLOCK_EXCL));
 	}
 
 	if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
-		if (!(lock_flags & XFS_IOLOCK_SHARED))
-			return !debug_locks ||
-				lockdep_is_held_type(&VFS_I(ip)->i_rwsem, 0);
-		return rwsem_is_locked(&VFS_I(ip)->i_rwsem);
+		ASSERT(!(lock_flags & ~(XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)));
+		return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem,
+				(lock_flags & XFS_IOLOCK_SHARED),
+				(lock_flags & XFS_IOLOCK_EXCL));
 	}
 
 	ASSERT(0);
-	return 0;
+	return false;
 }
 #endif
 
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 492e53992fa9..3d7ce355407d 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -416,7 +416,7 @@ void		xfs_ilock(xfs_inode_t *, uint);
 int		xfs_ilock_nowait(xfs_inode_t *, uint);
 void		xfs_iunlock(xfs_inode_t *, uint);
 void		xfs_ilock_demote(xfs_inode_t *, uint);
-int		xfs_isilocked(xfs_inode_t *, uint);
+bool		xfs_isilocked(xfs_inode_t *, uint);
 uint		xfs_ilock_data_map_shared(struct xfs_inode *);
 uint		xfs_ilock_attr_map_shared(struct xfs_inode *);
 
-- 
2.24.1