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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 551DCC64E8A for ; Mon, 30 Nov 2020 09:10:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09CB5207BC for ; Mon, 30 Nov 2020 09:10:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726671AbgK3JKH (ORCPT ); Mon, 30 Nov 2020 04:10:07 -0500 Received: from mx2.suse.de ([195.135.220.15]:38752 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726345AbgK3JKH (ORCPT ); Mon, 30 Nov 2020 04:10:07 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 84675AC6A; Mon, 30 Nov 2020 09:09:25 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 0D4011E131B; Mon, 30 Nov 2020 10:09:25 +0100 (CET) Date: Mon, 30 Nov 2020 10:09:25 +0100 From: Jan Kara To: Christoph Hellwig Cc: Jens Axboe , Tejun Heo , Josef Bacik , Coly Li , Mike Snitzer , Greg Kroah-Hartman , Jan Kara , Johannes Thumshirn , dm-devel@redhat.com, Jan Kara , linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 16/45] block: switch bdgrab to use igrab Message-ID: <20201130090925.GB11250@quack2.suse.cz> References: <20201128161510.347752-1-hch@lst.de> <20201128161510.347752-17-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201128161510.347752-17-hch@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Sat 28-11-20 17:14:41, Christoph Hellwig wrote: > All of the current callers already have a reference, but to prepare for > additional users ensure bdgrab returns NULL if the block device is beeing ^^^ being > freed. > > Signed-off-by: Christoph Hellwig Otherwise looks good. Feel free to add: Reviewed-by: Jan Kara Honza > --- > fs/block_dev.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index d707ab376da86e..962fabe8a67b83 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -894,10 +894,14 @@ static struct block_device *bdget(dev_t dev) > /** > * bdgrab -- Grab a reference to an already referenced block device > * @bdev: Block device to grab a reference to. > + * > + * Returns the block_device with an additional reference when successful, > + * or NULL if the inode is already beeing freed. > */ > struct block_device *bdgrab(struct block_device *bdev) > { > - ihold(bdev->bd_inode); > + if (!igrab(bdev->bd_inode)) > + return NULL; > return bdev; > } > EXPORT_SYMBOL(bdgrab); > -- > 2.29.2 > -- Jan Kara SUSE Labs, CR