From patchwork Mon Feb 20 11:16:05 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9582625 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7B8486042F for ; Mon, 20 Feb 2017 11:25:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6C35C287FA for ; Mon, 20 Feb 2017 11:25:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5DC0428864; Mon, 20 Feb 2017 11:25:58 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable 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 DB564287FA for ; Mon, 20 Feb 2017 11:25:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753172AbdBTLZq (ORCPT ); Mon, 20 Feb 2017 06:25:46 -0500 Received: from mga05.intel.com ([192.55.52.43]:39427 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752672AbdBTLYY (ORCPT ); Mon, 20 Feb 2017 06:24:24 -0500 Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP; 20 Feb 2017 03:24:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,186,1484035200"; d="scan'208";a="50229458" Received: from elena-thinkpad-x230.fi.intel.com ([10.237.72.69]) by orsmga002.jf.intel.com with ESMTP; 20 Feb 2017 03:24:19 -0800 From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-btrfs@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, axboe@kernel.dk, fujita.tomonori@lab.ntt.co.jp, mingo@redhat.com, clm@fb.com, jbacik@fb.com, dsterba@suse.com, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 2/5] block: convert blk_queue_tag.refcnt from atomic_t to refcount_t Date: Mon, 20 Feb 2017 13:16:05 +0200 Message-Id: <1487589368-17666-3-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487589368-17666-1-git-send-email-elena.reshetova@intel.com> References: <1487589368-17666-1-git-send-email-elena.reshetova@intel.com> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- block/blk-tag.c | 8 ++++---- include/linux/blkdev.h | 3 ++- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/block/blk-tag.c b/block/blk-tag.c index 07cc329..d83555e 100644 --- a/block/blk-tag.c +++ b/block/blk-tag.c @@ -35,7 +35,7 @@ EXPORT_SYMBOL(blk_queue_find_tag); */ void blk_free_tags(struct blk_queue_tag *bqt) { - if (atomic_dec_and_test(&bqt->refcnt)) { + if (refcount_dec_and_test(&bqt->refcnt)) { BUG_ON(find_first_bit(bqt->tag_map, bqt->max_depth) < bqt->max_depth); @@ -130,7 +130,7 @@ static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q, if (init_tag_map(q, tags, depth)) goto fail; - atomic_set(&tags->refcnt, 1); + refcount_set(&tags->refcnt, 1); tags->alloc_policy = alloc_policy; tags->next_tag = 0; return tags; @@ -180,7 +180,7 @@ int blk_queue_init_tags(struct request_queue *q, int depth, queue_flag_set(QUEUE_FLAG_QUEUED, q); return 0; } else - atomic_inc(&tags->refcnt); + refcount_inc(&tags->refcnt); /* * assign it, all done @@ -225,7 +225,7 @@ int blk_queue_resize_tags(struct request_queue *q, int new_depth) * Currently cannot replace a shared tag map with a new * one, so error out if this is the case */ - if (atomic_read(&bqt->refcnt) != 1) + if (refcount_read(&bqt->refcnt) != 1) return -EBUSY; /* diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index aecca0e..95ef11c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -25,6 +25,7 @@ #include #include #include +#include struct module; struct scsi_ioctl_command; @@ -288,7 +289,7 @@ struct blk_queue_tag { unsigned long *tag_map; /* bit map of free/busy tags */ int max_depth; /* what we will send to device */ int real_max_depth; /* what the array can hold */ - atomic_t refcnt; /* map can be shared */ + refcount_t refcnt; /* map can be shared */ int alloc_policy; /* tag allocation policy */ int next_tag; /* next tag */ };