Re: [PATCH] usbnet: fix skb traversing races during unlink

[Ming Lei <tom.leiming-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Sun, Apr 29, 2012 at 10:18 AM, David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> wrote:
> From: Ming Lei <tom.leiming-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Date: Fri, 27 Apr 2012 18:21:35 +0800
>
>> +/*The caller must hold list->lock*/
>
> Please put spaces in your comments, like this:
>
> /* The caller must hold list->lock */
>
>> +
>> +             /*speedup unlink by blocking resubmit*/
>
> Same here.

OK, will do it.

>>
>> -             entry = (struct skb_data *) skb->cb;
>> +             skb_queue_walk(q, skb) {
>> +                     entry = (struct skb_data *) skb->cb;
>> +                     if (entry->state != unlink_start)
>> +                             break;
>> +             }
>> +             if (skb == (struct sk_buff *)q)
>> +                     break;
>
> Please do not expose the internal details of SKB lists
> with a test like this.  Eventually this will all be
> converted to struct list_head and this kind of test
> will cause unnecessary pain for such a conversion.
>
> Instead, code it like this, as you would for a loop
> using list_for_each*() or similar:
>
>        skb_queue_walk(q, skb) {
>                if (condition)
>                        goto found;
>        }
>        /* No matching entry. */
>        break;
> found:

Good suggestion, will do it.


Thanks,
-- 
Ming Lei
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