ml_iterator_remove

Remove now obsolete mountlist_lock.  Keep struct mount element mnt_list
and now static mountlist for gdb and pstat.

diff -r bb476fea44cd -r 40e001e33fe6 sys/kern/vfs_mount.c
--- a/sys/kern/vfs_mount.c	Thu Mar 30 11:17:57 2017 +0200
+++ b/sys/kern/vfs_mount.c	Thu Mar 30 11:17:57 2017 +0200
@@ -117,9 +117,8 @@
 /* Root filesystem. */
 vnode_t *			rootvnode;
 
-/* Mounted filesystem list. */
-struct mntlist			mountlist;
-kmutex_t			mountlist_lock;
+/* Mounted filesystem list (pstat and gdb only). */
+static struct mntlist mountlist;
 int vnode_offset_next_by_mount	/* XXX: ugly hack for pstat.c */
     = offsetof(vnode_impl_t, vi_mntvnodes.tqe_next);
 
@@ -139,7 +138,6 @@
 	TAILQ_INIT(&mount_list);
 	TAILQ_INIT(&mountlist);
 	mutex_init(&mount_list_lock, MUTEX_DEFAULT, IPL_NONE);
-	mutex_init(&mountlist_lock, MUTEX_DEFAULT, IPL_NONE);
 	mutex_init(&mntvnode_lock, MUTEX_DEFAULT, IPL_NONE);
 	mutex_init(&vfs_list_lock, MUTEX_DEFAULT, IPL_NONE);
 
@@ -1580,11 +1578,8 @@
 	me = mountlist_alloc(ME_MOUNT, mp);
 	mutex_enter(&mount_list_lock);
 	TAILQ_INSERT_TAIL(&mount_list, me, me_list);
+	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
 	mutex_exit(&mount_list_lock);
-
-	mutex_enter(&mountlist_lock);
-	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
-	mutex_exit(&mountlist_lock);
 }
 
 void
@@ -1598,12 +1593,9 @@
 			break;
 	KASSERT(me != NULL);
 	TAILQ_REMOVE(&mount_list, me, me_list);
+	TAILQ_REMOVE(&mountlist, mp, mnt_list);
 	mutex_exit(&mount_list_lock);
 	mountlist_free(me);
-
-	mutex_enter(&mountlist_lock);
-	TAILQ_REMOVE(&mountlist, mp, mnt_list);
-	mutex_exit(&mountlist_lock);
 }
 
 /*
diff -r bb476fea44cd -r 40e001e33fe6 sys/sys/mount.h
--- a/sys/sys/mount.h	Thu Mar 30 11:17:57 2017 +0200
+++ b/sys/sys/mount.h	Thu Mar 30 11:17:57 2017 +0200
@@ -466,10 +466,9 @@
 void	vfs_syncer_add_to_worklist(struct mount *);
 void	vfs_syncer_remove_from_worklist(struct mount *);
 
-extern	TAILQ_HEAD(mntlist, mount) mountlist;	/* mounted filesystem list */
+TAILQ_HEAD(mntlist, mount);
 extern	struct vfsops *vfssw[];			/* filesystem type table */
 extern	int nvfssw;
-extern  kmutex_t mountlist_lock;
 extern	kmutex_t vfs_list_lock;
 
 void	vfs_mount_sysinit(void);