On 10/29/2018 07:41 PM, Cong Wang wrote:
> On Mon, Oct 29, 2018 at 7:25 PM Eric Dumazet <eric.duma...@gmail.com> wrote:
>>
>>
>>
>> On 10/29/2018 07:21 PM, Cong Wang wrote:
>>> On Mon, Oct 29, 2018 at 7:14 PM Eric Dumazet <eric.duma...@gmail.com> wrote:
>>>>
>>>> Would not it be simpler to set ip_summed to CHECKSUM_NONE (no need to save
>>>> old_csum) ?
>>>
>>> For !CHECKSUM_COMPLETE, ip_summed should be untouched, right?
>>>
>>> If you mean only setting to CHECKSUM_NONE for CHECKSUM_COMPLETE case,
>>> the end result may not be simpler.
>>
>> I meant to reinstate what was there before my patch in this error case
>>
>> if (skb->ip_summed == CHECKSUM_COMPLETE)
>> skb->ip_summed = CHECKSUM_NONE;
>>
>> That would only be run in error (quite unlikely) path, instead of saving
>> old_csum in all cases.
>
> I know your point, however, I am not sure that is a desired behavior.
>
> On failure, I think the whole skb should be restored to its previous state
> before entering this function, changing it to CHECKSUM_NONE on failure
> is inconsistent with success case.
>
Before my patch, we were changing skb->ip_summed to CHECKSUM_NONE,
so why suddenly we need to be consistent ?
In any case, ip_check_defrag() should really drop this skb, as for other
allocation
failures (like skb_share_check()), if really we want consistency.
