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 DB4F3C021B8 for ; Wed, 26 Feb 2025 16:21:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 60FBC28000A; Wed, 26 Feb 2025 11:21:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5C08A280001; Wed, 26 Feb 2025 11:21:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4AFB528000A; Wed, 26 Feb 2025 11:21:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 30F94280001 for ; Wed, 26 Feb 2025 11:21:55 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 1178CA4743 for ; Wed, 26 Feb 2025 16:21:53 +0000 (UTC) X-FDA: 83162612148.05.0CF01FB Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf18.hostedemail.com (Postfix) with ESMTP id C15541C0017 for ; Wed, 26 Feb 2025 16:21:50 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="Eb9L4/4r"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of djwong@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=djwong@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1740586911; a=rsa-sha256; cv=none; b=HWYAGK/i8trHq24tnNaKlz8O9kqbRGQMNAaEQlxlU884fHtJPyAPZaq3T2IzXIw15Nbru1 7NsZSzaEfmDa5IPdmsq3M6WipbyNQPJZO+MU23EX61p7KHxv2uMZrfD7YinZvqoQx8dqne 63ft7OYtGKulxqZa5tNqFkD+AN3KBrE= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="Eb9L4/4r"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of djwong@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=djwong@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1740586911; 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-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=6GXJ4UO9aFb7Np5SgXLJv11kNBkQdWHAjyKflIrfvE0=; b=s+wewbkNzXVgBnU0UpRR+ZYK1nbPCdbSLwVcqM6rCtzNL41YUVxvTZ/yrP6RnqMyV7+ZIw +QpcVQ7e1LhZtLnfnYJipkxUOXNh5XmSi0YbiOVFC6liz5S9XKQwpKyipcMS347xXB4oUY XefyZUvzzJ9LbHJ/3RSkix+cJW+g6Ks= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 9E4555C642D; Wed, 26 Feb 2025 16:21:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E20BC4CED6; Wed, 26 Feb 2025 16:21:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740586909; bh=joeQv285/J1l5VQPEP4BktUvhjdG3K+nqWq4ufXR1fE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Eb9L4/4r+StwOmEAlbB2c3kZz68F3AWEZGDCgAP7NRRP9waAbBEtU/Xe56HyI41B8 AmqOhgnj4JR/5O1nJNgSjkMjjPhahFoOLiTnUgCLMO6jLCLGzKkNMBt9hw0v2u/q4z o7e2QOsKYvdbP74994J/lf7JvHmH3hW6FwvqfW+rhGBSpidiRWBJKjC4MT8UISFxgJ TfNDJNiwWHNiXF1QQbn765xX6kI/+jBahVNyVmw+Y+nqOvolDMxsC9R3SD9OCv9NbT vA7tiTbiFJiBxe4+SAhmoEA9fZ40nkU8H7jbXHbnfETQPWhPWP+w53TTbZIHUxPBCF bJh955hr0oWug== Date: Wed, 26 Feb 2025 08:21:48 -0800 From: "Darrick J. Wong" To: "Matthew Wilcox (Oracle)" Cc: Andrew Morton , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] mm: Assert the folio is locked in folio_start_writeback() Message-ID: <20250226162148.GA6225@frogsfrogsfrogs> References: <20250226153614.3774896-1-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250226153614.3774896-1-willy@infradead.org> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C15541C0017 X-Stat-Signature: koqs6ttt99sknt5kt1jacmtfb3snhadc X-Rspam-User: X-HE-Tag: 1740586910-482530 X-HE-Meta: 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 QpOtRgPv oP952qQDnFpc4pVzFl6O0qA0GX63XmvRN8yT8drF0XW0hh5pv//l630dEVEcXDfSIDDVkKAZNAkxJB4O/PEz6XHCTE6tLpAaLbhkpQVy3l05NFXK4awcVXzpglBI8seheobqSuLwg7yt7vXlm5esEGGE8QeuDSh5PFCtxqaQoP1OLmWJGUaCCD3Gm6rGeSrGkvLK8l7yiowmfimvXUkgrIhvR0PzkXU7EBjNnmSkdS8pd/uUmYIDS7ko5xm8Nw3juR8CSmy1csxBsm+WTfWYLxcj36PKxwv4kGBCleyK69YOoKFUgRjpCt7SglsVGo+Tl1ZeTYzavP+QklpFHkjhN4CKX2jqw01r02NbLXwD0YZUxIOMJFxQz1DN4Kw85W8OszUGp 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: List-Subscribe: List-Unsubscribe: On Wed, Feb 26, 2025 at 03:36:12PM +0000, Matthew Wilcox (Oracle) wrote: > The folio must be locked when we start writeback in order to > prevent writeback from being started twice on the same folio. > I don't expect this to catch any problems, but it should be > good documentation. > > Signed-off-by: Matthew Wilcox (Oracle) LGTM Reviewed-by: "Darrick J. Wong" --D > --- > mm/page-writeback.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index eb55ece39c56..8b325aa525eb 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -3109,6 +3109,7 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) > int access_ret; > > VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); > + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); > > if (mapping && mapping_use_writeback_tags(mapping)) { > XA_STATE(xas, &mapping->i_pages, folio_index(folio)); > -- > 2.47.2 > >