ksmbd: filelock: move file locking definitions to separate header file

The file locking definitions have lived in fs.h since the dawn of time,
but they are only used by a small subset of the source files that
include it.

Move the file locking definitions to a new header file, and add the
appropriate #include directives to the source files that need them. By
doing this we trim down fs.h a bit and limit the amount of rebuilding
that has to be done when we make changes to the file locking APIs.

Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: Steve French <stfrench@microsoft.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

Author: jtlayton

smb2pdu.c

@@ -13,6 +13,10 @@
 #include <linux/falloc.h>
 #include <linux/crc32.h>
 #include <linux/mount.h>
+#include <linux/version.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
+#include <linux/filelock.h>
+#endif
 
 #include "glob.h"
 #include "smb2pdu.h"

vfs.c

@@ -6,10 +6,13 @@
 
 #include <linux/kernel.h>
 #include <linux/fs.h>
+#include <linux/version.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
+#include <linux/filelock.h>
+#endif
 #include <linux/uaccess.h>
 #include <linux/backing-dev.h>
 #include <linux/writeback.h>
-#include <linux/version.h>
 #include <linux/xattr.h>
 #include <linux/falloc.h>
 #if LINUX_VERSION_CODE < KERNEL_VERSION(5, 18, 0)

vfs_cache.c

@@ -5,6 +5,10 @@
  */
 
 #include <linux/fs.h>
+#include <linux/version.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
+#include <linux/filelock.h>
+#endif
 #include <linux/slab.h>
 #include <linux/vmalloc.h>