Re: [PATCH] net: caif: Don't act on notification for non-caif devices

From: Sjur BrÃndeland
Date: Tue Jan 24 2012 - 10:06:32 EST


Hi Sasha,

>> Nack, we have to handle other device types than just ARPHDR_CAIF after
>> introducing CAIF over USB/NCM.
> What my patch did was simply move the type check to above the net_generic call,
> it didn't add any new checks - which according to what you said, you'll need to do anyway.

As I said I, don't think your patch would work. Try to see what happens if
dev->type != ARPHDR_CAIF and caifd != NULL. Then the statement:

if (caifd == NULL && dev->type != ARPHRD_CAIF)
return 0;
is very different from:

if (dev->type != ARPHRD_CAIF)
return 0;
...
if (caifd == NULL)
return 0;

Anyway, another option could be to explicitly check if name space is
initialized,
similar to what net_generic() does,e.g. something like:

diff --git a/net/caif/caif_dev.c b/net/caif/caif_dev.c
index 673728a..3197bc2 100644
--- a/net/caif/caif_dev.c
+++ b/net/caif/caif_dev.c
@@ -371,6 +371,13 @@ static int caif_device_notify(struct notifier_block *me, un
struct cflayer *layer, *link_support;
int head_room = 0;
struct caif_device_entry_list *caifdevs;
+ int len;
+
+ rcu_read_lock();
+ len = rcu_dereference(dev_net(dev)->gen)->len;
+ rcu_read_unlock();
+ if (caif_net_id > len)
+ return 0;

cfg = get_cfcnfg(dev_net(dev));
caifdevs = caif_device_list(dev_net(dev));
--

Regards,
Sjur
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