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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 2839AC3815B for ; Thu, 16 Apr 2020 16:55:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F27182222D for ; Thu, 16 Apr 2020 16:55:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="TtpFsDnd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733074AbgDPQzP (ORCPT ); Thu, 16 Apr 2020 12:55:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728132AbgDPQzJ (ORCPT ); Thu, 16 Apr 2020 12:55:09 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2CA09C061A0C; Thu, 16 Apr 2020 09:55:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=yvc/LqWGsJQoZlzdhGNWD1srRYLVYt4uaD0vPdNMB/k=; b=TtpFsDndFzKEeaCi+FfFKf3vIS 4e3tsEwhHvzFrELaNwGr9SuEzMjm8fvlAqYdy8nS7Aom0GITGft2woimjU3pCuW7TLSB0ixSnvleO uYZ7OYH6Ma2hIHuH/rBFX2+aUuy1z2qiqXRG2B3HcIuDwswvkWiF6nIxUkNtUBVIcxMadOovqqLtX C59E0nu5bXctij3iLddqbWVK6NIijgrIjSvBkrD0ZcIcbG1UnkyC48SoubF0kTwYBtyBUh6mW6CVM EFyUg++lyPnL7dmYgB9bjKwXrY7TrREkzJLtRcaG6VAmIVNvDVkK7hWOI9kcquhsh2vfoU1nSimVo S9w3qwOw==; Received: from [2001:4bb8:184:4aa1:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jP7n5-00021E-9m; Thu, 16 Apr 2020 16:55:03 +0000 From: Christoph Hellwig To: axboe@kernel.dk Cc: yuyufen@huawei.com, tj@kernel.org, jack@suse.cz, bvanassche@acm.org, tytso@mit.edu, gregkh@linuxfoundation.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/8] bdi: add a ->dev_name field to struct backing_dev_info Date: Thu, 16 Apr 2020 18:54:48 +0200 Message-Id: <20200416165453.1080463-4-hch@lst.de> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200416165453.1080463-1-hch@lst.de> References: <20200416165453.1080463-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Cache a copy of the name for the life time of the backing_dev_info structure so that we can reference it even after unregistering. Fixes: 68f23b89067f ("memcg: fix a crash in wb_workfn when a device disappears") Reported-by: Yufen Yu Signed-off-by: Christoph Hellwig --- include/linux/backing-dev-defs.h | 1 + mm/backing-dev.c | 5 +++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 4fc87dee005a..2849bdbb3acb 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -220,6 +220,7 @@ struct backing_dev_info { wait_queue_head_t wb_waitq; struct device *dev; + char dev_name[64]; struct device *owner; struct timer_list laptop_mode_wb_timer; diff --git a/mm/backing-dev.c b/mm/backing-dev.c index c2c44c89ee5d..efc5b83acd2d 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -938,7 +938,8 @@ int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args) if (bdi->dev) /* The driver needs to use separate queues per device */ return 0; - dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args); + vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args); + dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name); if (IS_ERR(dev)) return PTR_ERR(dev); @@ -1047,7 +1048,7 @@ const char *bdi_dev_name(struct backing_dev_info *bdi) { if (!bdi || !bdi->dev) return bdi_unknown_name; - return dev_name(bdi->dev); + return bdi->dev_name; } EXPORT_SYMBOL_GPL(bdi_dev_name); -- 2.25.1