From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753277AbeDKNBo (ORCPT ); Wed, 11 Apr 2018 09:01:44 -0400 Received: from sesbmg22.ericsson.net ([193.180.251.48]:53792 "EHLO sesbmg22.ericsson.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753017AbeDKNBm (ORCPT ); Wed, 11 Apr 2018 09:01:42 -0400 X-AuditID: c1b4fb30-e6c349c000005e22-1c-5ace0734a050 From: Jon Maloy To: Ying Xue , Jia-Ju Bai , "davem@davemloft.net" CC: "netdev@vger.kernel.org" , "tipc-discussion@lists.sourceforge.net" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create Thread-Topic: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create Thread-Index: AQHT0X9aNgww/cwaY0uyVLV74ARKhaP7XCsAgAArH9A= Date: Wed, 11 Apr 2018 13:01:37 +0000 Message-ID: References: <1523442262-4823-1-git-send-email-baijiaju1990@gmail.com> <7bf48d79-54fe-421a-e04c-f2d6cd2c71e2@windriver.com> In-Reply-To: <7bf48d79-54fe-421a-e04c-f2d6cd2c71e2@windriver.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=jon.maloy@ericsson.com; 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Jon Maloy > ; davem@davemloft.net > Cc: netdev@vger.kernel.org; tipc-discussion@lists.sourceforge.net; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in > tipc_mon_create > > On 04/11/2018 06:24 PM, Jia-Ju Bai wrote: > > tipc_mon_create() is never called in atomic context. > > > > The call chain ending up at tipc_mon_create() is: > > [1] tipc_mon_create() <- tipc_enable_bearer() <- > > tipc_nl_bearer_enable() > > tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this > > function is not called in atomic context. > > > > Despite never getting called from atomic context, > > tipc_mon_create() calls kzalloc() with GFP_ATOMIC, which does not > > sleep for allocation. > > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, > which > > can sleep and improve the possibility of successful allocation. > > > > This is found by a static analysis tool named DCNS written by myself. > > And I also manually check it. > > > > Signed-off-by: Jia-Ju Bai > > Acked-by: Ying Xue Acked-by: Jon Maloy > > > --- > > v2: > > * Modify the description of GFP_ATOMIC in v1. > > Thank Eric for good advice. > > v3: > > * Modify wrong text in description in v2. > > Thank Ying for good advice. > > --- > > net/tipc/monitor.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c index > > 9e109bb..9714d80 100644 > > --- a/net/tipc/monitor.c > > +++ b/net/tipc/monitor.c > > @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id) > > if (tn->monitors[bearer_id]) > > return 0; > > > > - mon = kzalloc(sizeof(*mon), GFP_ATOMIC); > > - self = kzalloc(sizeof(*self), GFP_ATOMIC); > > - dom = kzalloc(sizeof(*dom), GFP_ATOMIC); > > + mon = kzalloc(sizeof(*mon), GFP_KERNEL); > > + self = kzalloc(sizeof(*self), GFP_KERNEL); > > + dom = kzalloc(sizeof(*dom), GFP_KERNEL); > > if (!mon || !self || !dom) { > > kfree(mon); > > kfree(self); > >