Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753081AbdF0LlD (ORCPT ); Tue, 27 Jun 2017 07:41:03 -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 S1751605AbdF0Lku (ORCPT ); Tue, 27 Jun 2017 07:40:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,399,1493708400"; d="scan'208";a="872136682" 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 4/5] block: convert io_context.active_ref from atomic_t to refcount_t Date: Tue, 27 Jun 2017 14:39:59 +0300 Message-Id: <1498563601-10949-5-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-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3560 Lines: 108 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/bfq-iosched.c | 2 +- block/blk-ioc.c | 4 ++-- block/cfq-iosched.c | 4 ++-- include/linux/iocontext.h | 6 +++--- 4 files changed, 8 insertions(+), 8 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index ed93da2..3a525ab 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -3988,7 +3988,7 @@ static void bfq_update_idle_window(struct bfq_data *bfqd, enable_idle = bfq_bfqq_idle_window(bfqq); - if (atomic_read(&bic->icq.ioc->active_ref) == 0 || + if (refcount_read(&bic->icq.ioc->active_ref) == 0 || bfqd->bfq_slice_idle == 0 || (bfqd->hw_tag && BFQQ_SEEKY(bfqq) && bfqq->wr_coeff == 1)) diff --git a/block/blk-ioc.c b/block/blk-ioc.c index 63898d2..69704d2 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -176,7 +176,7 @@ void put_io_context_active(struct io_context *ioc) unsigned long flags; struct io_cq *icq; - if (!atomic_dec_and_test(&ioc->active_ref)) { + if (!refcount_dec_and_test(&ioc->active_ref)) { put_io_context(ioc); return; } @@ -275,7 +275,7 @@ int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node) /* initialize */ atomic_long_set(&ioc->refcount, 1); atomic_set(&ioc->nr_tasks, 1); - atomic_set(&ioc->active_ref, 1); + refcount_set(&ioc->active_ref, 1); spin_lock_init(&ioc->lock); INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH); INIT_HLIST_HEAD(&ioc->icq_list); diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index b7e9c7f..07c416a 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2973,7 +2973,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) * task has exited, don't wait */ cic = cfqd->active_cic; - if (!cic || !atomic_read(&cic->icq.ioc->active_ref)) + if (!cic || !refcount_read(&cic->icq.ioc->active_ref)) return; /* @@ -3965,7 +3965,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfqq->next_rq && req_noidle(cfqq->next_rq)) enable_idle = 0; - else if (!atomic_read(&cic->icq.ioc->active_ref) || + else if (!refcount_read(&cic->icq.ioc->active_ref) || !cfqd->cfq_slice_idle || (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) enable_idle = 0; diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h index df38db2..e47b907 100644 --- a/include/linux/iocontext.h +++ b/include/linux/iocontext.h @@ -3,6 +3,7 @@ #include #include +#include #include enum { @@ -96,7 +97,7 @@ struct io_cq { */ struct io_context { atomic_long_t refcount; - atomic_t active_ref; + refcount_t active_ref; atomic_t nr_tasks; /* all the fields below are protected by this lock */ @@ -128,9 +129,8 @@ struct io_context { static inline void get_io_context_active(struct io_context *ioc) { WARN_ON_ONCE(atomic_long_read(&ioc->refcount) <= 0); - WARN_ON_ONCE(atomic_read(&ioc->active_ref) <= 0); atomic_long_inc(&ioc->refcount); - atomic_inc(&ioc->active_ref); + refcount_inc(&ioc->active_ref); } static inline void ioc_task_link(struct io_context *ioc) -- 2.7.4