[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <53550702.80807@cogentembedded.com>
Date: Mon, 21 Apr 2014 15:54:42 +0400
From: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To: "Li, ZhenHua" <zhen-hual@...com>
CC: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Veaceslav Falico <vfalico@...hat.com>,
Nicolas Dichtel <nicolas.dichtel@...nd.com>,
Jiri Pirko <jiri@...nulli.us>,
stephen hemminger <stephen@...workplumber.org>,
Jerry Chu <hkchu@...gle.com>,
Sathya Perla <sathya.perla@...lex.com>,
Subbu Seetharaman <subbu.seetharaman@...lex.com>,
Ajit Khaparde <ajit.khaparde@...lex.com>,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] net: Add rtnl_lock for netif_device_attach/detach
Hello.
On 21-04-2014 10:30, Li, ZhenHua wrote:
> The comment is trying to explain why add a lock here.
I can read, thanks. :-)
I was wondering about the kernel-doc comment style you've used; AFAIK,
it's only good for documenting functions and data structures. The normal
multi-line comment style in the networking code is this:
/* bla
* bla
*/
>>> From: "Li, Zhen-Hua" <zhen-hual@...com>
>>> As netif_running is called in netif_device_attach/detach. There should be
>>> rtnl_lock/unlock called, to avoid dev stat change during netif_device_attach
>>> and detach being called.
>>> I checked NIC some drivers, some of them have netif_device_attach/detach
>>> called between rtnl_lock/unlock, while some drivers do not.
>>> This patch is tring to find a generic way to fix this for all NIC drivers.
>>> Signed-off-by: Li, Zhen-Hua <zhen-hual@...com>
>>> ---
>>> net/core/dev.c | 18 ++++++++++++++++++
>>> 1 file changed, 18 insertions(+)
>>> diff --git a/net/core/dev.c b/net/core/dev.c
>>> index 5b3042e..795bbc5 100644
>>> --- a/net/core/dev.c
>>> +++ b/net/core/dev.c
>>> @@ -2190,10 +2190,19 @@ EXPORT_SYMBOL(__dev_kfree_skb_any);
>>> */
>>> void netif_device_detach(struct net_device *dev)
>>> {
>>> + /**
>> Hm, why kernel-doc style comment here?
>>> + * As netif_running is called , rtnl_lock and unlock are needed to
Space before comma not needed.
>>> + * avoid __LINK_STATE_START bit changes during this function call.
>>> + */
>>> + int need_unlock;
>>> +
>>> + need_unlock = rtnl_trylock();
>>> if (test_and_clear_bit(__LINK_STATE_PRESENT, &dev->state) &&
>>> netif_running(dev)) {
>>> netif_tx_stop_all_queues(dev);
>>> }
>>> + if (need_unlock)
>>> + rtnl_unlock();
>>> }
>>> EXPORT_SYMBOL(netif_device_detach);
>>>
>>> @@ -2205,11 +2214,20 @@ EXPORT_SYMBOL(netif_device_detach);
>>> */
>>> void netif_device_attach(struct net_device *dev)
>>> {
>>> + /**
>> ... and here?
>>> + * As netif_running is called , rtnl_lock and unlock are needed to
Space before comma not needed.
>>> + * avoid __LINK_STATE_START bit changes during this function call.
>>> + */
WBR, Sergei
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists