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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id F12A4C19F4F for ; Wed, 8 May 2024 11:36:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 809216B014F; Wed, 8 May 2024 07:36:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B92D6B0151; Wed, 8 May 2024 07:36:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 65BDE6B0152; Wed, 8 May 2024 07:36:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 461C66B014F for ; Wed, 8 May 2024 07:36:54 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id E6E491407C5 for ; Wed, 8 May 2024 11:36:53 +0000 (UTC) X-FDA: 82095026706.28.EEC8E8B Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf06.hostedemail.com (Postfix) with ESMTP id B4410180012 for ; Wed, 8 May 2024 11:36:50 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=prTjolwE; dmarc=none; spf=none (imf06.hostedemail.com: domain of BATV+51ef0b7171324ca53c39+7563+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+51ef0b7171324ca53c39+7563+infradead.org+hch@bombadil.srs.infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1715168212; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=8rBSqqk3Dus3WYu5NpDl6sctlp3PQWFzSKoFRqkHQlo=; b=hh4D4TJqhndZDhuR14aNSWPFy1Bp2vNHVljpRnXLDuGb2W0rvYJfxrCzWiGJxrpCbFo2Ic Xm51I1XdUOBTlUJuQJn/EHt7ilShZZSvQlCFQMeVi57nFDymSVoVolgrCfzX6pYx2k/j6u BQSfIOU8R9fOuYYStNdyO3wbUtBPsZU= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=prTjolwE; dmarc=none; spf=none (imf06.hostedemail.com: domain of BATV+51ef0b7171324ca53c39+7563+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+51ef0b7171324ca53c39+7563+infradead.org+hch@bombadil.srs.infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1715168212; a=rsa-sha256; cv=none; b=Qp3W3yyrZ5lq02Kvxq7KhQ13JnM2UjPDXpFwDzOGxvDiUfUhpVeUxvxSEGwdKaVhDln48J lEO1RwJc0Lzvk5paCIjcyoPxXUDFx2vRLRG1MlNyqWTMdjbkE2TMM8qbGb9nsW229MbDvw 4ousRE5wgDuCyFP5jvT28NdkPSRL3x0= 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=8rBSqqk3Dus3WYu5NpDl6sctlp3PQWFzSKoFRqkHQlo=; b=prTjolwEd1YkvaTflW9dmNx2HO AG2tcaR6q+4iFyte+YucYkOlnUglinvPRfBljqY0fNtFz01mNoVPUbj9gtk5LzZAvKH/9JTj5uHYA w5faiFjWiGstG8W7eN9Yhxv7rpQwD4Lrfxk3HZfYNwoLf/g5xeiGIEiExKRQzGmOa2ODgQf6FvPnJ yWVNvY6pSWwsCDtMsmMeiwqhON68ROokIeRkz+uWMKgpfy+y970j1+I1uDYEfoLB4naHlT8c0cOx4 3IZrYCbf76VvU8QVBje3IXfGjZT4w9JjxisZWpBaHyhyXiYeKzo9yDIcxVvXwf2jziTizRfdlBdFb qHrBzCXg==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1s4fbE-0000000FGOB-1v4V; Wed, 08 May 2024 11:36:40 +0000 Date: Wed, 8 May 2024 04:36:40 -0700 From: Christoph Hellwig To: Matthew Wilcox Cc: Christoph Hellwig , Luis Chamberlain , akpm@linux-foundation.org, djwong@kernel.org, brauner@kernel.org, david@fromorbit.com, chandan.babu@oracle.com, hare@suse.de, ritesh.list@gmail.com, john.g.garry@oracle.com, ziy@nvidia.com, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, gost.dev@samsung.com, p.raghav@samsung.com, kernel@pankajraghav.com Subject: Re: [PATCH v5 07/11] iomap: fix iomap_dio_zero() for fs bs > system page size Message-ID: References: <20240503095353.3798063-1-mcgrof@kernel.org> <20240503095353.3798063-8-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam01 X-Stat-Signature: xb1pua4xuz7skpimuzau9ekunu79aqnp X-Rspam-User: X-Rspamd-Queue-Id: B4410180012 X-HE-Tag: 1715168210-569267 X-HE-Meta: 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 2yWe9n9J 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, May 08, 2024 at 05:24:53AM +0100, Matthew Wilcox wrote: > On Tue, May 07, 2024 at 09:13:17AM -0700, Christoph Hellwig wrote: > > On Tue, May 07, 2024 at 05:11:58PM +0100, Matthew Wilcox wrote: > > > > __bio_add_page(bio, page, len, 0); > > > > > > no? len can be > PAGE_SIZE. > > > > Yes. So what? > > the zero_page is only PAGE_SIZE bytes long. so you'd be writing > from the page that's after the zero page, whatever contents that has. Except that the whole point of the exercise is to use the huge folio so that we don't run past the end of the zero page. Yes, if we use ZERO_PAGE we need to chunk things up and use bio_add_page instead bio_page, check the return value and potentially deal with multiple bios. I'd rather avoid that, though.