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 24AFFC7EE24 for ; Thu, 18 May 2023 04:23:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230031AbjEREXh (ORCPT ); Thu, 18 May 2023 00:23:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230024AbjEREXe (ORCPT ); Thu, 18 May 2023 00:23:34 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2CCD4115; Wed, 17 May 2023 21:23:33 -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=Gz4yC3Stvw1RiajpLPjxfqT9qrTt5nqXEtmmWJNVot4=; b=MLgX4K1AqQKeK7TZ4COPSW6Ujt fY/9fO898DKOBVykm1UGxo/9r+hdTTCdKTKsJ//Bprx8iNG3kGjNZZFBfq1NIJJg7FgQGQz1IRuK1 xAJfg2f1s/ZYkf3ZW25iaQrgI92F9TtboESuzNrnzt8Y0Alob+sUQ8NTeDyxG5eRumN8GI68PcCDQ 6JmemAExml/C39zKJ91sfiwo2NmTX0Xxnvkc7+GrvnXe12Hb3Zqp9BhZS8ki76XZkX++53y4ilGsW GiHLpZYiZ5J0EWUQWZlJIqbcrZyLi4vFuHTJStJ3ofjQzEfim3lAfbxNyGwbluJ1Bekmx0jJJ3Y53 Ivf9rvLA==; Received: from [2001:4bb8:188:3dd5:c90:b13:29fb:f2b9] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1pzVAn-00BqNh-2v; Thu, 18 May 2023 04:23:30 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Al Viro , Christian Brauner , "Darrick J. Wong" , Jan Kara , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org Subject: [PATCH 02/13] block: refactor bd_may_claim Date: Thu, 18 May 2023 06:23:11 +0200 Message-Id: <20230518042323.663189-3-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230518042323.663189-1-hch@lst.de> References: <20230518042323.663189-1-hch@lst.de> 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 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The long if/else chain obsfucates the actual logic. Tidy it up to be more structured. Also drop the whole argument, as it can be trivially derived from bdev using bdev_whole, and having the bdev_whole in the function makes it easier to follow. Signed-off-by: Christoph Hellwig --- block/bdev.c | 40 ++++++++++++++++++++++------------------ 1 file changed, 22 insertions(+), 18 deletions(-) diff --git a/block/bdev.c b/block/bdev.c index 317bfd9cba40fa..080b5c83bfbc72 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -463,7 +463,6 @@ long nr_blockdev_pages(void) /** * bd_may_claim - test whether a block device can be claimed * @bdev: block device of interest - * @whole: whole block device containing @bdev, may equal @bdev * @holder: holder trying to claim @bdev * * Test whether @bdev can be claimed by @holder. @@ -474,22 +473,27 @@ long nr_blockdev_pages(void) * RETURNS: * %true if @bdev can be claimed, %false otherwise. */ -static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, - void *holder) +static bool bd_may_claim(struct block_device *bdev, void *holder) { - if (bdev->bd_holder == holder) - return true; /* already a holder */ - else if (bdev->bd_holder != NULL) - return false; /* held by someone else */ - else if (whole == bdev) - return true; /* is a whole device which isn't held */ - - else if (whole->bd_holder == bd_may_claim) - return true; /* is a partition of a device that is being partitioned */ - else if (whole->bd_holder != NULL) - return false; /* is a partition of a held device */ - else - return true; /* is a partition of an un-held device */ + struct block_device *whole = bdev_whole(bdev); + + if (bdev->bd_holder) { + /* + * The same holder can always re-claim. + */ + if (bdev->bd_holder == holder) + return true; + return false; + } + + /* + * If the whole devices holder is set to bd_may_claim, a partition on + * the device is claimed, but not the whole device. + */ + if (whole != bdev && + whole->bd_holder && whole->bd_holder != bd_may_claim) + return false; + return true; } /** @@ -513,7 +517,7 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder) retry: spin_lock(&bdev_lock); /* if someone else claimed, fail */ - if (!bd_may_claim(bdev, whole, holder)) { + if (!bd_may_claim(bdev, holder)) { spin_unlock(&bdev_lock); return -EBUSY; } @@ -559,7 +563,7 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder) struct block_device *whole = bdev_whole(bdev); spin_lock(&bdev_lock); - BUG_ON(!bd_may_claim(bdev, whole, holder)); + BUG_ON(!bd_may_claim(bdev, holder)); /* * Note that for a whole device bd_holders will be incremented twice, * and bd_holder will be set to bd_may_claim before being set to holder -- 2.39.2