Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964878AbaKMXiU (ORCPT ); Thu, 13 Nov 2014 18:38:20 -0500 Received: from mail-oi0-f49.google.com ([209.85.218.49]:37696 "EHLO mail-oi0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934432AbaKMXiR (ORCPT ); Thu, 13 Nov 2014 18:38:17 -0500 MIME-Version: 1.0 In-Reply-To: <20141113152247.GB1408@swordfish> References: <1415885857-5283-1-git-send-email-opensource.ganesh@gmail.com> <20141113152247.GB1408@swordfish> Date: Fri, 14 Nov 2014 07:38:16 +0800 Message-ID: Subject: Re: [PATCH 1/3] mm/zsmalloc: avoid unregister a NOT-registered zsmalloc zpool driver From: Ganesh Mahendran To: Sergey Senozhatsky Cc: Minchan Kim , Nitin Gupta , ddstreet@ieee.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello 2014-11-13 23:22 GMT+08:00 Sergey Senozhatsky : > On (11/13/14 21:37), Mahendran Ganesh wrote: >> Now zsmalloc can be registered as a zpool driver into zpool when >> CONFIG_ZPOOL is enabled. During the init of zsmalloc, when error happens, >> we need to do cleanup. But in current code, it will unregister a not yet >> registered zsmalloc zpool driver(*zs_zpool_driver*). >> >> This patch puts the cleanup in zs_init() instead of calling zs_exit() >> where it will unregister a not-registered zpool driver. >> >> Signed-off-by: Mahendran Ganesh >> --- >> mm/zsmalloc.c | 12 ++++++++---- >> 1 file changed, 8 insertions(+), 4 deletions(-) >> >> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c >> index 839a48c..3d2bb36 100644 >> --- a/mm/zsmalloc.c >> +++ b/mm/zsmalloc.c >> @@ -907,10 +907,8 @@ static int zs_init(void) >> __register_cpu_notifier(&zs_cpu_nb); >> for_each_online_cpu(cpu) { >> ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu); >> - if (notifier_to_errno(ret)) { >> - cpu_notifier_register_done(); >> + if (notifier_to_errno(ret)) >> goto fail; >> - } >> } >> >> cpu_notifier_register_done(); >> @@ -920,8 +918,14 @@ static int zs_init(void) >> #endif >> >> return 0; >> + >> fail: >> - zs_exit(); >> + for_each_online_cpu(cpu) >> + zs_cpu_notifier(NULL, CPU_UP_CANCELED, (void *)(long)cpu); >> + __unregister_cpu_notifier(&zs_cpu_nb); >> + >> + cpu_notifier_register_done(); >> + >> return notifier_to_errno(ret); > > so we duplicate same code, and there is a bit confusing part > now: zs_cpu_notifier(CPU_UP_CANCELED) and zs_cpu_notifier(CPU_DEAD) > calls. Thanks for your review. CPU_UP_CANCELED and CPU_DEAD have different scenario. CPU_UP_CANCELED is better for fail to complete initialization. While CPU_DEAD is better for exit(such as removing module) Thanks. > > how about something like this? > > Factor out zsmalloc cpu notifier unregistration code and call > it from both zs_exit() and zs_init() error path. > > Signed-off-by: Sergey Senozhatsky > > --- > > mm/zsmalloc.c | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index b3b57ef..c4d2d60 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -881,14 +881,10 @@ static struct notifier_block zs_cpu_nb = { > .notifier_call = zs_cpu_notifier > }; > > -static void zs_exit(void) > +static inline void zs_unregister_cpu_notifier() > { > int cpu; > > -#ifdef CONFIG_ZPOOL > - zpool_unregister_driver(&zs_zpool_driver); > -#endif > - > cpu_notifier_register_begin(); > > for_each_online_cpu(cpu) > @@ -898,6 +894,14 @@ static void zs_exit(void) > cpu_notifier_register_done(); > } > > +static void zs_exit(void) > +{ > +#ifdef CONFIG_ZPOOL > + zpool_unregister_driver(&zs_zpool_driver); > +#endif > + zs_unregister_cpu_notifier(); > +} > + > static int zs_init(void) > { > int cpu, ret; > @@ -907,10 +911,8 @@ static int zs_init(void) > __register_cpu_notifier(&zs_cpu_nb); > for_each_online_cpu(cpu) { > ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu); > - if (notifier_to_errno(ret)) { > - cpu_notifier_register_done(); > + if (notifier_to_errno(ret)) > goto fail; > - } > } > > cpu_notifier_register_done(); > @@ -921,7 +923,7 @@ static int zs_init(void) > > return 0; > fail: > - zs_exit(); > + zs_unregister_cpu_notifier(); > return notifier_to_errno(ret); > } > -- 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/