From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 Date: Thu, 5 Oct 2017 09:33:28 -0700 From: Christoph Hellwig Subject: Re: false positive lockdep splat with loop device Message-ID: <20171005163328.GA3562@infradead.org> References: <20170926042421.GP10955@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Amir Goldstein Cc: Dave Chinner , "Darrick J. Wong" , xfs , Peter Zijlstra , Byungchul Park , linux-kernel , linux-fsdevel , linux-block 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); -- 2.14.1