Re: [PATCH] mac80211-hwsim: Don't enqueue pkts that do not want txstatus.

[Ben Greear <greearb@candelatech.com>]

On 02/24/2015 02:14 AM, Johannes Berg wrote:
> On Mon, 2015-02-23 at 09:38 -0800, Ben Greear wrote:
>
>>> This doesn't really seem right - essentially it means that whatever you
>>> just gave to userspace is now completely useless?
>>>
>>> It seems skb_orphan() could/should be put here.
>>
>> I don't understand your complaint, why is what I gave to user-space useless?
>
> userspace is supposed to give back the SKB pointer as a cookie when it
> reports whether or not it was transmitted correctly, and then we will
> free the SKB afterwards.

If there is no status to return, then why would user-space call back at all?

Should user-space *always* return a status even when not requested to?

Thanks,
Ben


> Note that I also just merged a patch from Bob in this area.
>
>> If we just orphan them, does that clean up the skb memory properly?
>
> No, of course not, but it removes it from socket accounting. This may be
> what you want, although I'm not really sure it's the right thing to do
> since it would make this behave differently than other drivers which
> also don't orphan the SKB (and shouldn't - you can consider the SKB on
> this queue as being on the HW DMA queue where it should still be
> accounted for correctly)
>
> I think perhaps you just want Bob's patch to fix the case of too slow
> userspace.
>
>> If not, what eventually frees the skb?
>
> The tx status path does.
>
> johannes
>

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com