From patchwork Wed Jul 13 11:31:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12916594 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 763A1C433EF for ; Wed, 13 Jul 2022 11:31:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235703AbiGMLbl (ORCPT ); Wed, 13 Jul 2022 07:31:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235603AbiGMLbk (ORCPT ); Wed, 13 Jul 2022 07:31:40 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8EBA1102726; Wed, 13 Jul 2022 04:31:39 -0700 (PDT) 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:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=W1e6MzbMvcjOzxPlhjQN2IPC6OQvXK65Jnlzyh8Wt5w=; b=Q5hDKDCBGnwfuAZzKk1G2iYRmr I41HgF/hfNYBkio2BSrRU0p9wo8Vy1rSPvf+OBdziTySpfTmdp6PVSjGmCkx4/BVegmiZW1OdVxNc zM+3CMELy8Hx5GZAmt1N2n4WLjOYdk3L76l/FIKhkpYROY6jqtpEqMBSxQy2EKudRi+dtG3zeF/ig 2ZXaQQLfBPksAMfRZzEk7L6e0lP9MZNQUvWRhrBIgzzO8DSVOte106vw/AUec6qGqUIbG9yhRi+hh m1sXFcEOKslxqocB6YHQuRENc7Yy99TBuH6UZ3K9O9eoFCrDmN8La7M7Fqx3n9zqAOKtj3splcoH1 9shTU5Xg==; Received: from ip4d15c27d.dynamic.kabel-deutschland.de ([77.21.194.125] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oBaaf-003A3r-A4; Wed, 13 Jul 2022 11:31:37 +0000 From: Christoph Hellwig To: Song Liu Cc: Logan Gunthorpe , linux-raid@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH 4/9] md: factor out the rdev overlaps check from rdev_size_store Date: Wed, 13 Jul 2022 13:31:20 +0200 Message-Id: <20220713113125.2232975-5-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220713113125.2232975-1-hch@lst.de> References: <20220713113125.2232975-1-hch@lst.de> MIME-Version: 1.0 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-block@vger.kernel.org This splits the code into nicely readable chunks and also avoids the refcount inc/dec manipulations. Signed-off-by: Christoph Hellwig --- drivers/md/md.c | 84 +++++++++++++++++++++++-------------------------- 1 file changed, 39 insertions(+), 45 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 3127dcb8102ce..5346135ab51c8 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -3344,14 +3344,33 @@ rdev_size_show(struct md_rdev *rdev, char *page) return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2); } -static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2) +static int md_rdevs_overlap(struct md_rdev *a, struct md_rdev *b) { /* check if two start/length pairs overlap */ - if (s1+l1 <= s2) - return 0; - if (s2+l2 <= s1) - return 0; - return 1; + if (a->data_offset + a->sectors <= b->data_offset) + return false; + if (b->data_offset + b->sectors <= a->data_offset) + return false; + return true; +} + +static bool md_rdev_overlaps(struct md_rdev *rdev) +{ + struct mddev *mddev; + struct md_rdev *rdev2; + + spin_lock(&all_mddevs_lock); + list_for_each_entry(mddev, &all_mddevs, all_mddevs) { + rdev_for_each(rdev2, mddev) { + if (rdev != rdev2 && rdev->bdev == rdev2->bdev && + md_rdevs_overlap(rdev, rdev2)) { + spin_unlock(&all_mddevs_lock); + return true; + } + } + } + spin_unlock(&all_mddevs_lock); + return false; } static int strict_blocks_to_sectors(const char *buf, sector_t *sectors) @@ -3403,46 +3422,21 @@ rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len) return -EINVAL; /* component must fit device */ rdev->sectors = sectors; - if (sectors > oldsectors && my_mddev->external) { - /* Need to check that all other rdevs with the same - * ->bdev do not overlap. 'rcu' is sufficient to walk - * the rdev lists safely. - * This check does not provide a hard guarantee, it - * just helps avoid dangerous mistakes. - */ - struct mddev *mddev; - int overlap = 0; - struct list_head *tmp; - rcu_read_lock(); - for_each_mddev(mddev, tmp) { - struct md_rdev *rdev2; - - rdev_for_each(rdev2, mddev) - if (rdev->bdev == rdev2->bdev && - rdev != rdev2 && - overlaps(rdev->data_offset, rdev->sectors, - rdev2->data_offset, - rdev2->sectors)) { - overlap = 1; - break; - } - if (overlap) { - mddev_put(mddev); - break; - } - } - rcu_read_unlock(); - if (overlap) { - /* Someone else could have slipped in a size - * change here, but doing so is just silly. - * We put oldsectors back because we *know* it is - * safe, and trust userspace not to race with - * itself - */ - rdev->sectors = oldsectors; - return -EBUSY; - } + /* + * Check that all other rdevs with the same bdev do not overlap. This + * check does not provide a hard guarantee, it just helps avoid + * dangerous mistakes. + */ + if (sectors > oldsectors && my_mddev->external && + md_rdev_overlaps(rdev)) { + /* + * Someone else could have slipped in a size change here, but + * doing so is just silly. We put oldsectors back because we + * know it is safe, and trust userspace not to race with itself. + */ + rdev->sectors = oldsectors; + return -EBUSY; } return len; }