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 9AB3CC001DF for ; Tue, 1 Aug 2023 17:49:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1F783940043; Tue, 1 Aug 2023 13:49:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A81C940010; Tue, 1 Aug 2023 13:49:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 096FC940043; Tue, 1 Aug 2023 13:49:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id EB4C2940010 for ; Tue, 1 Aug 2023 13:49:19 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id C1B7980535 for ; Tue, 1 Aug 2023 17:49:19 +0000 (UTC) X-FDA: 81076272438.29.93D252D Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf30.hostedemail.com (Postfix) with ESMTP id 09E1680031 for ; Tue, 1 Aug 2023 17:22:13 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=qLtl8QrL; spf=none (imf30.hostedemail.com: domain of BATV+44153ebb3f5e3de177ba+7282+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+44153ebb3f5e3de177ba+7282+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1690910534; 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-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=KI7aWHvSDXmhxzHfaalEHg4CqR1G5kysSfQhkQhMeeQ=; b=rpNdowE9fBYdrND/mQZsC/Gl13Kp0lSJvAG1Kz3b4UCmBA4VIUhlGTw5zX6341qnZ5NcBM j0cibWWhbM6n1Tl1AarjAXC8gi4OF2Vj7alPS9QJZs1NSQGOU+nO7XD+U7UBw5RIKFXy+F aMHTtwelIaZnrNIyRPnoSI/bf8HD0ug= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=qLtl8QrL; spf=none (imf30.hostedemail.com: domain of BATV+44153ebb3f5e3de177ba+7282+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+44153ebb3f5e3de177ba+7282+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1690910534; a=rsa-sha256; cv=none; b=7nG1CGLWbbuc9DjnGl2B1iXl4dteytd7T2xqPNb/gfIVc46GYwDhpWsZYxmXDEaJRUcMY2 1/D8HQvM0Ma4FNF2TWteXtJJTSb5J6/+IlDLNmogzby/9N+Z/+AByFkg0TANN2ct2NIFq2 Aj6ySlYumnmGyDEQzlVnEjzzg0NpFtc= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: Content-ID:Content-Description:In-Reply-To:References; bh=KI7aWHvSDXmhxzHfaalEHg4CqR1G5kysSfQhkQhMeeQ=; b=qLtl8QrLHzZR3bYK8L7GyySX8I ui/iPrQEaxDZ2ZfzYU1SSMTdWMhYkH2FZalEJBLrDXxNFoxLyiD+GaUFKCZtShgsGlroNSM1mewkz +K/5Jr4SSllO2UPuk94IptV+69fj7W5EzAdX/LSLm+iTyTRDAoc9qtXJQ+EMnVvG7gkK9vU9FkQ0r NaOSrDyin3BImtyOJRNdcR2ARCfAsk+XaJq0t65rk7g31lgKcxWP7BClvjbC1USYJoOzx2Bkv7Jqb s/Fj+GkFQtVxuKUX/FEtRMkAUM2OUYp0VnZF8342fy2gBxlRZw8VAauLrGHX/slpc1KmP7X/xB17c 1PuKU2JQ==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qQt4P-002uSp-2j; Tue, 01 Aug 2023 17:22:06 +0000 From: Christoph Hellwig To: Jens Axboe Cc: "Darrick J. Wong" , Andrew Morton , Matthew Wilcox , Christian Brauner , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: allow building a kernel without buffer_heads v3 Date: Tue, 1 Aug 2023 19:21:55 +0200 Message-Id: <20230801172201.1923299-1-hch@lst.de> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Queue-Id: 09E1680031 X-Rspam-User: X-Stat-Signature: u813y4xrf67e8newajwse7ocr9651md3 X-Rspamd-Server: rspam01 X-HE-Tag: 1690910533-844307 X-HE-Meta: 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 gIxAHpqw qmUfuwK30zcXNMAVTsQ3AVa6vVF0nGLCe+3KRJtdLGYYRRBXYDZwAXsNkOIUGzsETTYk8fD93XMTij3auTN7KabEh9H45IbP/WA+nF+Re2uhuVm+KIt20jZO/cZ2Lgql+XLajaflAamz0mZv2D/LZVN8pgocShRyz2eVLVB34oI/alnCNG5Ec75Lqps+P3CJ63Ow2a1qQ+UNd3Y0sCJtZWQ1mGZ1Yeek69GSQMA4OgQttaG1ySQluuzXsnUxqf6P2AiV8WZuHRYh1d7Caa5lT6rtQqxA069C+vht5lpG28okMxF51c1a5xyxQqa9I3mLkGmZWQWTWlEPa83BG21J6WOVA5cebAPNn9wMzn+8D5Vjcj1FcYMvmJzAYsQu4T9bb8j4Wwbk9my8IERzSBTntWGNHQrDUK/ijAjpOlt5C6bybEFjNdh6kKAKPKkHrcbMvdDiWz62p0N4OIaM= 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: Hi all, This series allows to build a kernel without buffer_heads, which I think is useful to show where the dependencies are, and maybe also for some very much limited environments, where people just needs xfs and/or btrfs and some of the read-only block based file systems. It first switches buffered writes (but not writeback) for block devices to use iomap unconditionally, but still using buffer_heads, and then adds a CONFIG_BUFFER_HEAD selected by all file systems that need it (which is most block based file systems), makes the buffer_head support in iomap optional, and adds an alternative implementation of the block device address_operations using iomap. This latter implementation will also be useful to support block size > PAGE_SIZE for block device nodes as buffer_heads won't work very well for that. Note that for now the md software raid drivers is also disabled as it has some (rather questionable) buffer_head usage in the unconditionally built bitmap code. I have a series pending to make the bitmap code conditional and deprecated it, but it hasn't been merged yet. This series is against Jens' for-6.6/block branch. Changes since v2: - fix handling of a negative return value from blkdev_direct_IO - drop a WARN_ON that can happen when resizing block devices - define away IOMAP_F_BUFFER_HEAD to keep the intrusions to the iomap code minimal (even if that's not quite my preferred style) Changes since v1: - drop the already merged prep patches - depend on FS_IOMAP not IOMAP - pick a better new name for block_page_mkwrite_return