From patchwork Thu Oct 5 16:33:28 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 9987537 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 39080602B8 for ; Thu, 5 Oct 2017 16:33:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2BD7F28A58 for ; Thu, 5 Oct 2017 16:33:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 20C4928CF0; Thu, 5 Oct 2017 16:33:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AF95728A58 for ; Thu, 5 Oct 2017 16:33:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751443AbdJEQdf (ORCPT ); Thu, 5 Oct 2017 12:33:35 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:49831 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751144AbdJEQdd (ORCPT ); Thu, 5 Oct 2017 12:33:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=6d8bLhaR2bcHvVFmIxCWHtlmQYYnFWciGKQ/i5k7Wkc=; b=qjgX7gylMdFmEGaBOPAc561Pt 8nv8x8dbuaI2U/XEFnkQ43nj8T3quA9bXGxjlinilD1Y7CPpWdyC6rDqDIEQ252lQ5oVeZolXQjI2 liSfWVWYciQ79yIansMef2Owj/PEoPFhibJcvTBor9jf04Ie2WVrKVyteY2DvD66MTs4vq/IKcacs kaTwFxMtFjZDygeJgHOtQ6TKxyvDpN4hxELEluSxX3OByCPnH6jcVOaw23X6Nh7MBFYUAJlM5fZoQ UAYJStNl9X8fyV17FeSQiDDGcdSET5bs/RdEDDPyMJxetvPMKHF0LpiyzflhrAgXtrDkrk23lP3u1 IzyomwDow==; Received: from hch by bombadil.infradead.org with local (Exim 4.87 #1 (Red Hat Linux)) id 1e095U-00017y-UO; Thu, 05 Oct 2017 16:33:28 +0000 Date: Thu, 5 Oct 2017 09:33:28 -0700 From: Christoph Hellwig To: Amir Goldstein Cc: Dave Chinner , "Darrick J. Wong" , xfs , Peter Zijlstra , Byungchul Park , linux-kernel , linux-fsdevel , linux-block Subject: Re: false positive lockdep splat with loop device Message-ID: <20171005163328.GA3562@infradead.org> References: <20170926042421.GP10955@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.3 (2017-05-23) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Does the patch below fix the warning for you? --- From 28aae7104425433d39e6142adcd5b88dc5b0ad5f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 5 Oct 2017 18:31:02 +0200 Subject: block: use DECLARE_COMPLETION_ONSTACK in submit_bio_wait This way we get our lockdep annotations right in case multiple layers in the stack use submit_bio_wait. It also happens to simplify the code by getting rid of the submit_bio_ret structure. Signed-off-by: Christoph Hellwig --- block/bio.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) diff --git a/block/bio.c b/block/bio.c index 8338304ea256..4e18e959fc0a 100644 --- a/block/bio.c +++ b/block/bio.c @@ -917,17 +917,9 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) } EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages); -struct submit_bio_ret { - struct completion event; - int error; -}; - static void submit_bio_wait_endio(struct bio *bio) { - struct submit_bio_ret *ret = bio->bi_private; - - ret->error = blk_status_to_errno(bio->bi_status); - complete(&ret->event); + complete(bio->bi_private); } /** @@ -943,16 +935,15 @@ static void submit_bio_wait_endio(struct bio *bio) */ int submit_bio_wait(struct bio *bio) { - struct submit_bio_ret ret; + DECLARE_COMPLETION_ONSTACK(done); - init_completion(&ret.event); - bio->bi_private = &ret; + bio->bi_private = &done; bio->bi_end_io = submit_bio_wait_endio; bio->bi_opf |= REQ_SYNC; submit_bio(bio); - wait_for_completion_io(&ret.event); + wait_for_completion_io(&done); - return ret.error; + return blk_status_to_errno(bio->bi_status); } EXPORT_SYMBOL(submit_bio_wait);