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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D715C4332B for ; Mon, 23 Mar 2020 14:04:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4AB622077D for ; Mon, 23 Mar 2020 14:04:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584972267; bh=s2NbQJjle+0OzIirrPM+TLR0bDT4Bsx1I69q/jCQKMY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=KkqRKD7kqL22xpcTlp62yvaoGFbnmksNga9eo5rhhJVIoQljKEn3WkQicXGw5Bi2a SbMxcNjE+yAInzoKuiu+22GeqwFqrqbwpFLqhxgWsxkHV8iRJLuq6jIATh5NWjYg2/ i8JS+vEIDtxiDK3nik6n6Dn8sKuWLxBseG0MJVUo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728501AbgCWOE0 (ORCPT ); Mon, 23 Mar 2020 10:04:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:36788 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728446AbgCWOE0 (ORCPT ); Mon, 23 Mar 2020 10:04:26 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DD2512076A; Mon, 23 Mar 2020 14:04:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584972264; bh=s2NbQJjle+0OzIirrPM+TLR0bDT4Bsx1I69q/jCQKMY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Y0JLIB8OTtTcgH+XZTnGtGS+5XCEF0ztyGqJtW8wr61SkA5In0i+4cekXFDZXJzF0 GcwQQNRsU5DczS2q9HjtUwmz23116PdLu5KEsRDBfGqQh2a4f5qmHa3vG8OAHlT+QU omIZbpEWtAgyWLKvvWPZRKzww5YGqxS6EpWcyBoI= Date: Mon, 23 Mar 2020 15:04:21 +0100 From: Greg KH To: Yufen Yu Cc: axboe@kernel.dk, linux-block@vger.kernel.org, tj@kernel.org, jack@suse.cz, bvanassche@acm.org, tytso@mit.edu Subject: Re: [PATCH v3 4/4] bdi: protect bdi->dev with spinlock Message-ID: <20200323140421.GA7976@kroah.com> References: <20200323132254.47157-1-yuyufen@huawei.com> <20200323132254.47157-5-yuyufen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200323132254.47157-5-yuyufen@huawei.com> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Mar 23, 2020 at 09:22:54PM +0800, Yufen Yu wrote: > diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h > index 82d2401fec37..1c0e2d0d6236 100644 > --- a/include/linux/backing-dev.h > +++ b/include/linux/backing-dev.h > @@ -525,12 +525,16 @@ static inline const char *bdi_dev_name(struct backing_dev_info *bdi) > static inline char *bdi_get_dev_name(struct backing_dev_info *bdi, > char *dname, int len) > { > + spin_lock_irq(&bdi->lock); > if (!bdi || !bdi->dev) { > + spin_unlock_irq(&bdi->lock); You can't test for (!bdi) right after you accessed bdi->lock :(