+/*
+ * We do use our own empty page to avoid interference with other users
+ * of ZERO_PAGE(), such as /dev/zero
+ */
+static struct page *__xip_sparse_page;
+
+static struct page *xip_sparse_page(void)
+{
+ if (!__xip_sparse_page) {
+ unsigned long zeroes = get_zeroed_page(GFP_HIGHUSER);
+ if (zeroes) {
+ static DEFINE_SPINLOCK(xip_alloc_lock);
+ spin_lock(&xip_alloc_lock);
+ if (!__xip_sparse_page)
+ __xip_sparse_page = virt_to_page(zeroes);
+ else
+ free_page(zeroes);
+ spin_unlock(&xip_alloc_lock);
+ }
+ }
+ return __xip_sparse_page;
+}
+