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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39EE5C433F5 for ; Wed, 3 Nov 2021 15:46:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AE0F610E5 for ; Wed, 3 Nov 2021 15:46:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232469AbhKCPt1 (ORCPT ); Wed, 3 Nov 2021 11:49:27 -0400 Received: from verein.lst.de ([213.95.11.211]:59923 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232125AbhKCPt0 (ORCPT ); Wed, 3 Nov 2021 11:49:26 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 1BB3468C4E; Wed, 3 Nov 2021 16:46:45 +0100 (CET) Date: Wed, 3 Nov 2021 16:46:44 +0100 From: Christoph Hellwig To: Coly Li Cc: axboe@kernel.dk, linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, Christoph Hellwig , stable@vger.kernel.org Subject: Re: [PATCH] bcache: Revert "bcache: use bvec_virt" Message-ID: <20211103154644.GA30686@lst.de> References: <20211103151041.70516-1-colyli@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211103151041.70516-1-colyli@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On Wed, Nov 03, 2021 at 11:10:41PM +0800, Coly Li wrote: > diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c > index 93b67b8d31c3..88c573eeb598 100644 > --- a/drivers/md/bcache/btree.c > +++ b/drivers/md/bcache/btree.c > @@ -378,7 +378,7 @@ static void do_btree_node_write(struct btree *b) > struct bvec_iter_all iter_all; > > bio_for_each_segment_all(bv, b->bio, iter_all) { > - memcpy(bvec_virt(bv), addr, PAGE_SIZE); > + memcpy(page_address(bv->bv_page), addr, PAGE_SIZE); How could there be an offset? bch_bio_alloc_pages allocates a fresh page for each vec, and bio_for_each_segment_all iterates page by page. IFF there is an offset there is proble in the surrounding code as bch_bio_alloc_pages assumes that it is called on a freshly allocate and initialized bio.