Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751787AbdCXNtg (ORCPT ); Fri, 24 Mar 2017 09:49:36 -0400 Received: from mail-vk0-f68.google.com ([209.85.213.68]:35723 "EHLO mail-vk0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751477AbdCXNt1 (ORCPT ); Fri, 24 Mar 2017 09:49:27 -0400 MIME-Version: 1.0 In-Reply-To: <1489752646-8749-6-git-send-email-elena.reshetova@intel.com> References: <1489752646-8749-1-git-send-email-elena.reshetova@intel.com> <1489752646-8749-6-git-send-email-elena.reshetova@intel.com> From: Ilya Dryomov Date: Fri, 24 Mar 2017 14:49:24 +0100 Message-ID: Subject: Re: [PATCH 05/23] net, ceph: convert ceph_osd.o_ref from atomic_t to refcount_t To: Elena Reshetova Cc: netdev , "linux-kernel@vger.kernel.org" , linux-rdma@vger.kernel.org, "David S. Miller" , linux-x25@vger.kernel.org, linux-sctp@vger.kernel.org, vyasevich@gmail.com, nhorman@tuxdriver.com, linux-hams@vger.kernel.org, linux-nfs@vger.kernel.org, Ceph Development , "Yan, Zheng" , Sage Weil , bfields@fieldses.org, Jeff Layton , steffen.klassert@secunet.com, Herbert Xu , santosh.shilimkar@oracle.com, jreuter@yaina.de, ralf@linux-mips.org, peterz@infradead.org, Kees Cook , Hans Liljestrand , David Windsor Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3475 Lines: 92 On Fri, Mar 17, 2017 at 1:10 PM, Elena Reshetova wrote: > 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 > --- > include/linux/ceph/osd_client.h | 3 ++- > net/ceph/osd_client.c | 16 ++++++++-------- > 2 files changed, 10 insertions(+), 9 deletions(-) > > diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h > index 2ea0c28..5ce0cd6 100644 > --- a/include/linux/ceph/osd_client.h > +++ b/include/linux/ceph/osd_client.h > @@ -5,6 +5,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -27,7 +28,7 @@ typedef void (*ceph_osdc_callback_t)(struct ceph_osd_request *); > > /* a given osd we're communicating with */ > struct ceph_osd { > - atomic_t o_ref; > + refcount_t o_ref; > struct ceph_osd_client *o_osdc; > int o_osd; > int o_incarnation; > diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c > index b65bbf9..99a51f0 100644 > --- a/net/ceph/osd_client.c > +++ b/net/ceph/osd_client.c > @@ -1005,7 +1005,7 @@ static bool osd_registered(struct ceph_osd *osd) > */ > static void osd_init(struct ceph_osd *osd) > { > - atomic_set(&osd->o_ref, 1); > + refcount_set(&osd->o_ref, 1); > RB_CLEAR_NODE(&osd->o_node); > osd->o_requests = RB_ROOT; > osd->o_linger_requests = RB_ROOT; > @@ -1050,9 +1050,9 @@ static struct ceph_osd *create_osd(struct ceph_osd_client *osdc, int onum) > > static struct ceph_osd *get_osd(struct ceph_osd *osd) > { > - if (atomic_inc_not_zero(&osd->o_ref)) { > - dout("get_osd %p %d -> %d\n", osd, atomic_read(&osd->o_ref)-1, > - atomic_read(&osd->o_ref)); > + if (refcount_inc_not_zero(&osd->o_ref)) { > + dout("get_osd %p %d -> %d\n", osd, refcount_read(&osd->o_ref)-1, > + refcount_read(&osd->o_ref)); > return osd; > } else { > dout("get_osd %p FAIL\n", osd); > @@ -1062,9 +1062,9 @@ static struct ceph_osd *get_osd(struct ceph_osd *osd) > > static void put_osd(struct ceph_osd *osd) > { > - dout("put_osd %p %d -> %d\n", osd, atomic_read(&osd->o_ref), > - atomic_read(&osd->o_ref) - 1); > - if (atomic_dec_and_test(&osd->o_ref)) { > + dout("put_osd %p %d -> %d\n", osd, refcount_read(&osd->o_ref), > + refcount_read(&osd->o_ref) - 1); > + if (refcount_dec_and_test(&osd->o_ref)) { > osd_cleanup(osd); > kfree(osd); > } > @@ -4092,7 +4092,7 @@ void ceph_osdc_stop(struct ceph_osd_client *osdc) > close_osd(osd); > } > up_write(&osdc->lock); > - WARN_ON(atomic_read(&osdc->homeless_osd.o_ref) != 1); > + WARN_ON(refcount_read(&osdc->homeless_osd.o_ref) != 1); > osd_cleanup(&osdc->homeless_osd); > > WARN_ON(!list_empty(&osdc->osd_lru)); Applied. Thanks, Ilya