Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756584AbbEVINU (ORCPT ); Fri, 22 May 2015 04:13:20 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:54793 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754889AbbEVINL (ORCPT ); Fri, 22 May 2015 04:13:11 -0400 Message-ID: <1432282245.25585.6.camel@haakon3.risingtidesystems.com> Subject: Re: [PATCH 2/4] target: Drop lun_sep_lock for se_lun->lun_se_dev RCU usage From: "Nicholas A. Bellinger" To: Hannes Reinecke Cc: "Nicholas A. Bellinger" , target-devel , linux-scsi , linux-kernel , Christoph Hellwig In-Reply-To: <555EE165.3090709@suse.de> References: <1432278417-29994-1-git-send-email-nab@daterainc.com> <1432278417-29994-3-git-send-email-nab@daterainc.com> <555EE165.3090709@suse.de> Content-Type: text/plain; charset="UTF-8" Date: Fri, 22 May 2015 01:10:45 -0700 Mime-Version: 1.0 X-Mailer: Evolution 3.4.4-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3266 Lines: 86 On Fri, 2015-05-22 at 09:57 +0200, Hannes Reinecke wrote: > On 05/22/2015 09:06 AM, Nicholas A. Bellinger wrote: > > From: Nicholas Bellinger > > > > With se_port and t10_alua_tg_pt_gp_member being absored into se_lun, > > there is no need for an extra lock to protect se_lun->lun_se_dev > > assignment. > > > > Also, convert se_lun->lun_stats to use atomic_long_t within the > > target_complete_ok_work() completion callback. > > > > Reported-by: Christoph Hellwig > > Signed-off-by: Nicholas Bellinger > > --- > > drivers/target/target_core_device.c | 1 - > > drivers/target/target_core_stat.c | 65 +++++++++++++++++----------------- > > drivers/target/target_core_tpg.c | 8 ++--- > > drivers/target/target_core_transport.c | 22 ++++-------- > > include/target/target_core_base.h | 9 +++-- > > 5 files changed, 46 insertions(+), 59 deletions(-) > > > > [ .. ] > > > diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c > > index 8764f1c..f60b74e 100644 > > --- a/drivers/target/target_core_tpg.c > > +++ b/drivers/target/target_core_tpg.c > > @@ -601,7 +601,6 @@ struct se_lun *core_tpg_alloc_lun( > > lun->lun_link_magic = SE_LUN_LINK_MAGIC; > > lun->lun_status = TRANSPORT_LUN_STATUS_FREE; > > atomic_set(&lun->lun_acl_count, 0); > > - spin_lock_init(&lun->lun_sep_lock); > > init_completion(&lun->lun_ref_comp); > > INIT_LIST_HEAD(&lun->lun_deve_list); > > INIT_LIST_HEAD(&lun->lun_dev_link); > > @@ -638,10 +637,7 @@ int core_tpg_add_lun( > > target_attach_tg_pt_gp(lun, dev->t10_alua.default_tg_pt_gp); > > > > mutex_lock(&tpg->tpg_lun_mutex); > > - > > - spin_lock(&lun->lun_sep_lock); > > - lun->lun_se_dev = dev; > > - spin_unlock(&lun->lun_sep_lock); > > + rcu_assign_pointer(lun->lun_se_dev, dev); > > > > spin_lock(&dev->se_port_lock); > > dev->export_count++; > > @@ -683,7 +679,7 @@ void core_tpg_remove_lun( > > dev->export_count--; > > spin_unlock(&dev->se_port_lock); > > > > - lun->lun_se_dev = NULL; > > + rcu_assign_pointer(lun->lun_se_dev, NULL); > > } > > > > lun->lun_status = TRANSPORT_LUN_STATUS_FREE; > Doesn't this need to go under 'dev->se_port_lock' like in > core_tgp_add_lun() ? Yes, of course. Adding the following change, and will squash into the original patch soon. Thanks for reviewing Hannes! diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index aa08d6b..a3c9121 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -641,9 +641,9 @@ int core_tpg_add_lun( target_attach_tg_pt_gp(lun, dev->t10_alua.default_tg_pt_gp); mutex_lock(&tpg->tpg_lun_mutex); - rcu_assign_pointer(lun->lun_se_dev, dev); spin_lock(&dev->se_port_lock); + rcu_assign_pointer(lun->lun_se_dev, dev); dev->export_count++; list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list); spin_unlock(&dev->se_port_lock); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/