dax: Convert __dax_invalidate_entry to XArray

static int __dax_invalidate_entry(struct address_space *mapping,

					  pgoff_t index, bool trunc)

{

	XA_STATE(xas, &mapping->i_pages, index);

	int ret = 0;

	void *entry;

	struct radix_tree_root *pages = &mapping->i_pages;

	xa_lock_irq(pages);

	entry = get_unlocked_mapping_entry(mapping, index, NULL);

	xas_lock_irq(&xas);

	entry = get_unlocked_entry(&xas);

	if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))

		goto out;

	if (!trunc &&

	    (radix_tree_tag_get(pages, index, PAGECACHE_TAG_DIRTY) ||

	     radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE)))

	    (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) ||

	     xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE)))

		goto out;

	dax_disassociate_entry(entry, mapping, trunc);

	radix_tree_delete(pages, index);

	xas_store(&xas, NULL);

	mapping->nrexceptional--;

	ret = 1;

out:

	put_unlocked_mapping_entry(mapping, index, entry);

	xa_unlock_irq(pages);

	put_unlocked_entry(&xas, entry);

	xas_unlock_irq(&xas);

	return ret;

}

/*

 * Delete DAX entry at @index from @mapping.  Wait for it

 * to be unlocked before deleting it.