9P doesn't need BKL in ->umount_begin()

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/9p/vfs_super.c

@@ -37,7 +37,6 @@
 #include <linux/mount.h>
 #include <linux/idr.h>
 #include <linux/sched.h>
-#include <linux/smp_lock.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 
@@ -231,10 +230,8 @@ v9fs_umount_begin(struct super_block *sb)
 {
 	struct v9fs_session_info *v9ses;
 
-	lock_kernel();
 	v9ses = sb->s_fs_info;
 	v9fs_session_cancel(v9ses);
-	unlock_kernel();
 }
 
 static const struct super_operations v9fs_super_ops = {