From patchwork Thu May 18 04:23:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13246114 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 D523CC77B7A for ; Thu, 18 May 2023 04:23:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230029AbjEREXj (ORCPT ); Thu, 18 May 2023 00:23:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230030AbjEREXh (ORCPT ); Thu, 18 May 2023 00:23:37 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17A2D127; Wed, 17 May 2023 21:23:36 -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=0gTLAUlFe0DX2eUG/rV5llfv74gR91AkuRTXQ7aAQuQ=; b=vpKun/M7D8fB+iq2ZKgwFAQ4p2 pNP3Tg+9axrBNEubJQg3m+gmQmpPnkfnQcFCOYA2sHZsQgFMQ4t2ghibVnovVdw2HwaFSoa7SCQgD pumoqJ5nIqTSGrI6nhZ6dsFy53+HlFvD5VhoTB7dGw69iuHd0CuWYsrueshMbxjc9gDjsolAL93Ae LG4FApY/eymdtrqH8djMeWvw87kx7FL/kcQD4Zb9Z3Azz7zgliDMcXEJGLMJjnFlZfrqFxvHSAzDg iDjIwQeRFDCx0goyiNikg5LfXTottVh1GWPLUj7wamvbiDY0GocUY0vaUtiFlCRpbQaw8Mk3SbQfO fUKMkKrg==; 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 1pzVAq-00BqNr-2V; Thu, 18 May 2023 04:23:33 +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 03/13] block: turn bdev_lock into a mutex Date: Thu, 18 May 2023 06:23:12 +0200 Message-Id: <20230518042323.663189-4-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 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 There is no reason for this lock to spin, and being able to sleep under it will come in handy soon. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Acked-by: Christian Brauner --- block/bdev.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) diff --git a/block/bdev.c b/block/bdev.c index 080b5c83bfbc72..f5ffcac762e0cd 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -308,7 +308,7 @@ EXPORT_SYMBOL(thaw_bdev); * pseudo-fs */ -static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); +static __cacheline_aligned_in_smp DEFINE_MUTEX(bdev_lock); static struct kmem_cache * bdev_cachep __read_mostly; static struct inode *bdev_alloc_inode(struct super_block *sb) @@ -467,9 +467,6 @@ long nr_blockdev_pages(void) * * Test whether @bdev can be claimed by @holder. * - * CONTEXT: - * spin_lock(&bdev_lock). - * * RETURNS: * %true if @bdev can be claimed, %false otherwise. */ @@ -477,6 +474,8 @@ static bool bd_may_claim(struct block_device *bdev, void *holder) { struct block_device *whole = bdev_whole(bdev); + lockdep_assert_held(&bdev_lock); + if (bdev->bd_holder) { /* * The same holder can always re-claim. @@ -515,10 +514,10 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder) if (WARN_ON_ONCE(!holder)) return -EINVAL; retry: - spin_lock(&bdev_lock); + mutex_lock(&bdev_lock); /* if someone else claimed, fail */ if (!bd_may_claim(bdev, holder)) { - spin_unlock(&bdev_lock); + mutex_unlock(&bdev_lock); return -EBUSY; } @@ -528,7 +527,7 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder) DEFINE_WAIT(wait); prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); - spin_unlock(&bdev_lock); + mutex_unlock(&bdev_lock); schedule(); finish_wait(wq, &wait); goto retry; @@ -536,7 +535,7 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder) /* yay, all mine */ whole->bd_claiming = holder; - spin_unlock(&bdev_lock); + mutex_unlock(&bdev_lock); return 0; } EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */ @@ -562,7 +561,7 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder) { struct block_device *whole = bdev_whole(bdev); - spin_lock(&bdev_lock); + mutex_lock(&bdev_lock); BUG_ON(!bd_may_claim(bdev, holder)); /* * Note that for a whole device bd_holders will be incremented twice, @@ -573,7 +572,7 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder) bdev->bd_holders++; bdev->bd_holder = holder; bd_clear_claiming(whole, holder); - spin_unlock(&bdev_lock); + mutex_unlock(&bdev_lock); } /** @@ -587,9 +586,9 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder) */ void bd_abort_claiming(struct block_device *bdev, void *holder) { - spin_lock(&bdev_lock); + mutex_lock(&bdev_lock); bd_clear_claiming(bdev_whole(bdev), holder); - spin_unlock(&bdev_lock); + mutex_unlock(&bdev_lock); } EXPORT_SYMBOL(bd_abort_claiming); @@ -602,7 +601,7 @@ static void bd_end_claim(struct block_device *bdev) * Release a claim on the device. The holder fields are protected with * bdev_lock. open_mutex is used to synchronize disk_holder unlinking. */ - spin_lock(&bdev_lock); + mutex_lock(&bdev_lock); WARN_ON_ONCE(--bdev->bd_holders < 0); WARN_ON_ONCE(--whole->bd_holders < 0); if (!bdev->bd_holders) { @@ -612,7 +611,7 @@ static void bd_end_claim(struct block_device *bdev) } if (!whole->bd_holders) whole->bd_holder = NULL; - spin_unlock(&bdev_lock); + mutex_unlock(&bdev_lock); /* * If this was the last claim, remove holder link and unblock evpoll if