XArray: Fix xas_pause at ULONG_MAX
If we were unlucky enough to call xas_pause() when the index was at
ULONG_MAX (or a multi-slot entry which ends at ULONG_MAX), we would
wrap the index back around to 0 and restart the iteration from the
beginning. Use the XAS_BOUNDS state to indicate that we should just
stop the iteration.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index 7df4f7f..c477f22 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -1132,6 +1132,27 @@ static noinline void check_move_tiny(struct xarray *xa)
XA_BUG_ON(xa, !xa_empty(xa));
}
+static noinline void check_move_max(struct xarray *xa)
+{
+ XA_STATE(xas, xa, 0);
+
+ xa_store_index(xa, ULONG_MAX, GFP_KERNEL);
+ rcu_read_lock();
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX));
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL);
+ rcu_read_unlock();
+
+ xas_set(&xas, 0);
+ rcu_read_lock();
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX));
+ xas_pause(&xas);
+ XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL);
+ rcu_read_unlock();
+
+ xa_erase_index(xa, ULONG_MAX);
+ XA_BUG_ON(xa, !xa_empty(xa));
+}
+
static noinline void check_move_small(struct xarray *xa, unsigned long idx)
{
XA_STATE(xas, xa, 0);
@@ -1240,6 +1261,7 @@ static noinline void check_move(struct xarray *xa)
xa_destroy(xa);
check_move_tiny(xa);
+ check_move_max(xa);
for (i = 0; i < 16; i++)
check_move_small(xa, 1UL << i);