From patchwork Mon Aug 27 18:33:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Pittman X-Patchwork-Id: 10577465 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 19B95139B for ; Mon, 27 Aug 2018 18:33:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0B94029F11 for ; Mon, 27 Aug 2018 18:33:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F3ABB29FE1; Mon, 27 Aug 2018 18:33:14 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham 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 90B5629F11 for ; Mon, 27 Aug 2018 18:33:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727136AbeH0WU5 (ORCPT ); Mon, 27 Aug 2018 18:20:57 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57550 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726895AbeH0WU5 (ORCPT ); Mon, 27 Aug 2018 18:20:57 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C4FC88011059; Mon, 27 Aug 2018 18:33:12 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-121-244.rdu2.redhat.com [10.10.121.244]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9146A2026E18; Mon, 27 Aug 2018 18:33:12 +0000 (UTC) From: John Pittman To: axboe@kernel.dk Cc: linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, John Pittman Subject: [PATCH] block: bsg: move atomic_t ref_count variable to refcount API Date: Mon, 27 Aug 2018 14:33:05 -0400 Message-Id: <20180827183305.27722-1-jpittman@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 27 Aug 2018 18:33:12 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 27 Aug 2018 18:33:12 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jpittman@redhat.com' RCPT:'' Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, variable ref_count within the bsg_device struct is of type atomic_t. For variables being used as reference counters, the refcount API should be used instead of atomic. The newer refcount API works to prevent counter overflows and use-after-free bugs. So, move this varable from the atomic API to refcount, potentially avoiding the issues mentioned. Signed-off-by: John Pittman --- block/bsg.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/block/bsg.c b/block/bsg.c index db588add6ba6..9a442c23a715 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -37,7 +37,7 @@ struct bsg_device { struct request_queue *queue; spinlock_t lock; struct hlist_node dev_list; - atomic_t ref_count; + refcount_t ref_count; char name[20]; int max_queue; }; @@ -252,7 +252,7 @@ static int bsg_put_device(struct bsg_device *bd) mutex_lock(&bsg_mutex); - if (!atomic_dec_and_test(&bd->ref_count)) { + if (!refcount_dec_and_test(&bd->ref_count)) { mutex_unlock(&bsg_mutex); return 0; } @@ -290,7 +290,7 @@ static struct bsg_device *bsg_add_device(struct inode *inode, bd->queue = rq; - atomic_set(&bd->ref_count, 1); + refcount_set(&bd->ref_count, 1); hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); @@ -308,7 +308,7 @@ static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { if (bd->queue == q) { - atomic_inc(&bd->ref_count); + refcount_inc(&bd->ref_count); goto found; } }