lkml.org 
[lkml]   [2014]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [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@hp.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@hp.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



\
 
 \ /
  Last update: 2014-04-21 14:01    [W:0.039 / U:2.688 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site