From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4519CC10F29 for ; Tue, 17 Mar 2020 15:28:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0BCD820714 for ; Tue, 17 Mar 2020 15:28:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nNS0iOdm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726607AbgCQP2u (ORCPT ); Tue, 17 Mar 2020 11:28:50 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:52336 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726019AbgCQP2u (ORCPT ); Tue, 17 Mar 2020 11:28:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xJA9FFPfJkuq8fVzTKccTbceOpg3uJs1/00mKyQZnEc=; b=nNS0iOdmgHP2ZIGEAO0g8u8fHS TDvQDiQcFH1hBkh3Q5nsFQz5yj7wNCL9cCORyBIyR7V7GMpP/q/ZoUKULALuLr2IdVltjzsEIP4xU ZxpJAxHApbow3TTrO+kd7z8z5XjPJvXMEpQnHDINerFDHBgzwxx833CnsYL6lxI3noSayyLLf8qoR e4jvJjgerruwRQffudZlNvBPEa8TKXAtVTahVkqvpnOgladbVay0AMUHK92QgVxKvK4RBmQ5/1d1R +yWUabB4oYjjbTWqpMJSPZIicNbXxCNRb7EXNJSzuMNn4VGo1WST+AhzHDaLRUUWT0AbzpC+lzkCj r6J22hMQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jEE9C-0008Sr-5E; Tue, 17 Mar 2020 15:28:50 +0000 Date: Tue, 17 Mar 2020 08:28:50 -0700 From: Matthew Wilcox To: Jan Kara Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 2/8] xarray: Provide xas_erase() helper Message-ID: <20200317152850.GC22433@bombadil.infradead.org> References: <20200204142514.15826-1-jack@suse.cz> <20200204142514.15826-3-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200204142514.15826-3-jack@suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Feb 04, 2020 at 03:25:08PM +0100, Jan Kara wrote: > +void *xas_erase(struct xa_state *xas) > +{ > + void *entry; > + > + entry = xas_store(xas, NULL); > + xas_init_marks(xas); > + > + return entry; > +} > +EXPORT_SYMBOL(xas_erase); I didn't have a test case to show this, but ... +static noinline void check_multi_store_4(struct xarray *xa) +{ + XA_BUG_ON(xa, xa_marked(xa, XA_MARK_0)); + XA_BUG_ON(xa, !xa_empty(xa)); + + xa_store_index(xa, 0, GFP_KERNEL); + xa_store_index(xa, 2, GFP_KERNEL); + xa_set_mark(xa, 0, XA_MARK_0); + xa_set_mark(xa, 2, XA_MARK_0); + + xa_store_order(xa, 0, 2, NULL, GFP_KERNEL); + XA_BUG_ON(xa, xa_marked(xa, XA_MARK_0)); + xa_destroy(xa); +} shows a problem. Because we delete all the entries in the tree, xas_delete_node() sets the xas->xa_node to XAS_BOUNDS. This fixes it: @@ -492,7 +492,6 @@ static void xas_delete_node(struct xa_state *xas) if (!parent) { xas->xa->xa_head = NULL; - xas->xa_node = XAS_BOUNDS; return; } (it leaves xas->xa_node set to NULL, which makes the above work correctly because NULL is used to mean the one element at index 0 of the array) Now I'm wondering if it's going to break anything, though. The test suite runs successfully, but it can't be exhaustive.