From patchwork Tue Jun 27 11:39:57 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9811471 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 C4E836020A for ; Tue, 27 Jun 2017 11:42:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2BDCF2861D for ; Tue, 27 Jun 2017 11:42:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 209A328634; Tue, 27 Jun 2017 11:42:00 +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 C694B28639 for ; Tue, 27 Jun 2017 11:41:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753016AbdF0Lkx (ORCPT ); Tue, 27 Jun 2017 07:40:53 -0400 Received: from mga03.intel.com ([134.134.136.65]:5589 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752957AbdF0Lkr (ORCPT ); Tue, 27 Jun 2017 07:40:47 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Jun 2017 04:40:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,399,1493708400"; d="scan'208";a="872136629" Received: from elena-thinkpad-x230.fi.intel.com ([10.237.72.56]) by FMSMGA003.fm.intel.com with ESMTP; 27 Jun 2017 04:40:13 -0700 From: Elena Reshetova To: axboe@kernel.dk Cc: james.bottomley@hansenpartnership.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-btrfs@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, keescook@chromium.org, fujita.tomonori@lab.ntt.co.jp, mingo@redhat.com, clm@fb.com, jbacik@fb.com, dsterba@suse.com, Elena Reshetova , Hans Liljestrand , David Windsor Subject: [PATCH 2/5] block: convert blk_queue_tag.refcnt from atomic_t to refcount_t Date: Tue, 27 Jun 2017 14:39:57 +0300 Message-Id: <1498563601-10949-3-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1498563601-10949-1-git-send-email-elena.reshetova@intel.com> References: <1498563601-10949-1-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 1ddd36b..3efc8cf 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -26,6 +26,7 @@ #include #include #include +#include struct module; struct scsi_ioctl_command; @@ -293,7 +294,7 @@ 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 */ };