Commit 2fbe967b authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

XArray: Fix xa_erase of 2-byte aligned entries 



xas_store() was interpreting the entry it found in the array as a node
entry if the bottom two bits had value 2.  That's only true if either
the entry is in the root node or in a non-leaf node.

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent 962033d5

lib/test_xarray.c

+15 −1
Original line number Diff line number Diff line
@@ -1355,6 +1355,20 @@ static void check_align_1(struct xarray *xa, char *name) 
	xa_destroy(xa);

}



static void check_align_2(struct xarray *xa, char *name)

{

	int i;



	XA_BUG_ON(xa, !xa_empty(xa));



	for (i = 0; i < 8; i++) {

		XA_BUG_ON(xa, xa_store(xa, 0, name + i, GFP_KERNEL) != NULL);

		xa_erase(xa, 0);

	}



	XA_BUG_ON(xa, !xa_empty(xa));

}



static noinline void check_align(struct xarray *xa)

{

	char name[] = "Motorola 68000";
@@ -1363,7 +1377,7 @@ static noinline void check_align(struct xarray *xa) 
	check_align_1(xa, name + 1);

	check_align_1(xa, name + 2);

	check_align_1(xa, name + 3);

//	check_align_2(xa, name);

	check_align_2(xa, name);

}



static LIST_HEAD(shadow_nodes);

lib/xarray.c

+1 −1
Original line number Diff line number Diff line
@@ -800,7 +800,7 @@ void *xas_store(struct xa_state *xas, void *entry) 
		 * entry is set to NULL.

		 */

		rcu_assign_pointer(*slot, entry);

		if (xa_is_node(next))

		if (xa_is_node(next) && (!node || node->shift))

			xas_free_nodes(xas, xa_to_node(next));

		if (!node)

			break;