From patchwork Fri May 5 17:51:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13232931 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 E4150C7EE24 for ; Fri, 5 May 2023 17:53:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233249AbjEERxG (ORCPT ); Fri, 5 May 2023 13:53:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233207AbjEERwy (ORCPT ); Fri, 5 May 2023 13:52:54 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 426D13588; Fri, 5 May 2023 10:52:27 -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=lDMC1lrlYmdpYq8a/9apcmwTdFEQ6B63P/EyMNUb9bo=; b=KGOBjob5BNDZGN+OXEXxQ0zucA VfOTnXx25OzjOkrlEZkUgwRkGobiJy+pX2vjjSqrjumN5QZ2/hj5weuF3rAhp1rz8yYtX35y/Jw2v GiSNPxwJf1RHPkamgJ2fY9U+TVl/T485cC429b6EbtlV9J/qDn4OHiDwmm3lrLiM64h3Gi6AwRCH9 0n+Pa02rjkSqx3yhNwTtFBGthSuaC8nW8hzj7Kg3C4uxCc8L5YEjOo12QQn58YsYkqN2IkMRw61ck IQ0FaK/LMYUm9wrlYMi8M/ZUP99l7gDLDqr7rUvEnrwxt6djrJaiOkDk6KTOEglhAsT2ebq6lj1/E kiolEKtQ==; Received: from 66-46-223-221.dedicated.allstream.net ([66.46.223.221] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1puzax-00BSxb-23; Fri, 05 May 2023 17:51:51 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Al Viro , Christian Brauner , "Darrick J. Wong" , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org Subject: [PATCH 4/9] block: turn bdev_lock into a mutex Date: Fri, 5 May 2023 13:51:27 -0400 Message-Id: <20230505175132.2236632-5-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230505175132.2236632-1-hch@lst.de> References: <20230505175132.2236632-1-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 f2c7181b0bba7d..bad75f6cf8edcd 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) @@ -457,15 +457,14 @@ 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. */ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, void *holder) { + lockdep_assert_held(&bdev_lock); + if (bdev->bd_holder == holder) return true; /* already a holder */ else if (bdev->bd_holder != NULL) @@ -500,10 +499,10 @@ 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, whole, holder)) { - spin_unlock(&bdev_lock); + mutex_unlock(&bdev_lock); return -EBUSY; } @@ -513,7 +512,7 @@ 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; @@ -521,7 +520,7 @@ 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 */ @@ -547,7 +546,7 @@ 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, whole, holder)); /* * Note that for a whole device bd_holders will be incremented twice, @@ -558,7 +557,7 @@ 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); } /** @@ -572,9 +571,9 @@ 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); @@ -587,7 +586,7 @@ 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) { @@ -597,7 +596,7 @@ 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