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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E908AC76195 for ; Thu, 23 Mar 2023 10:39:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231594AbjCWKjD (ORCPT ); Thu, 23 Mar 2023 06:39:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229913AbjCWKic (ORCPT ); Thu, 23 Mar 2023 06:38:32 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 659683757A; Thu, 23 Mar 2023 03:35:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=HBrCuNH4R5xVEUODXfgFvseYVrpNbKOLURA5BAjbAEs=; b=nWqyk/EtC9rse1gAdHYp4M8ESS Z7Y5w49+4TDL9y3/5lTTaPWGhh7CgpiGCWXi6DtQlXOZ06TYKSd9LJvdXO4ni7mb6mn2re/JUof9J 8mgZM1/jgPcsd7lyXn8PJrMfBjxuut+uRyJj88Rqomtvo9cVs5/S0ZyI2wO2IobLbqLIQ/hMvWPMA aYL+FYr4CA5H9EbkWlre4jdMIsVgacLp6OmLcOTtng8XcOdr6OEveylnTVkF6PnOfkFymhDN0ZuSo EV947OC+1f+JCYcZ3b02bBYCDMe0IIDXMftx1qYl0pK97z3OFXdAwHJfiihd2e6FMBFxxX/xAAv0x mElzawHA==; Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1pfIII-001aoD-02; Thu, 23 Mar 2023 10:35:42 +0000 Date: Thu, 23 Mar 2023 03:35:41 -0700 From: Christoph Hellwig To: Pankaj Raghav Cc: senozhatsky@chromium.org, viro@zeniv.linux.org.uk, axboe@kernel.dk, willy@infradead.org, brauner@kernel.org, akpm@linux-foundation.org, minchan@kernel.org, hubcap@omnibond.com, martin@omnibond.com, mcgrof@kernel.org, devel@lists.orangefs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, gost.dev@samsung.com Subject: Re: [RFC v2 1/5] zram: remove zram_page_end_io function Message-ID: References: <20230322135013.197076-1-p.raghav@samsung.com> <20230322135013.197076-2-p.raghav@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230322135013.197076-2-p.raghav@samsung.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Mar 22, 2023 at 02:50:09PM +0100, Pankaj Raghav wrote: > - if (!parent) > - bio->bi_end_io = zram_page_end_io; > - else > + if (parent) I don't think a non-chained bio without and end_io handler can work. This !parent case seems to come from writeback_store, and as far as I can tell is broken already in the current code as it just fires off an async read without ever waiting for it, using an on-stack bio just to make things complicated. The bvec reading code in zram is a mess, but I have an idea how to clean it up with a little series that should also help with this issue.