From: Ying Xue <ying.xue@windriver.com>
To: Jia-Ju Bai <baijiaju1990@gmail.com>, <jon.maloy@ericsson.com>,
<davem@davemloft.net>
Cc: <netdev@vger.kernel.org>, <tipc-discussion@lists.sourceforge.net>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create
Date: Wed, 11 Apr 2018 18:11:40 +0800 [thread overview]
Message-ID: <73c0b7cb-5148-9c38-d45b-750f711b5570@windriver.com> (raw)
In-Reply-To: <1523323053-28127-1-git-send-email-baijiaju1990@gmail.com>
On 04/10/2018 09:17 AM, Jia-Ju Bai wrote:
> tipc_mon_create() is never called in atomic context.
>
> The call chain ending up at dn_route_init() is:
Sorry, I don't think there is any relationship between the following
call chain with dn_route_init().
> [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 sucessful allocation.
s/sucessful/successful
>
> 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 <baijiaju1990@gmail.com>> ---
> v2:
> * Modify the description of GFP_ATOMIC in v1.
> Thank Eric 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);
>
next prev parent reply other threads:[~2018-04-11 11:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-10 1:17 [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create Jia-Ju Bai
2018-04-11 10:11 ` Ying Xue [this message]
2018-04-11 10:18 ` Jia-Ju Bai
-- strict thread matches above, loose matches on Subject: below --
2018-04-10 1:16 Jia-Ju Bai
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