Re: [PATCH net-next] tcp: introduce tcp_try_coalesce

[Eric Dumazet <eric.dumazet@gmail.com>]

On Mon, 2012-04-23 at 22:46 -0400, David Miller wrote:

> Applied, thanks Eric.
> 
> Although I'd like to ask you to clean up tcp_try_coalesce() a bit.
> 
> It effectively returns a boolean, but you've clouded this up by
> returning an int and defining it in the comment to return "> 0" or
> not.
> 
> Just make it return a real bool.
> 
> I know why you did this, it makes the "eaten" code somewhat simpler in
> tcp_data_queue(), but overall it's more confusing how it is now.
> 
> People look at how the tcp_try_coalesce() return value is interpreted
> and say "in what cases can it return a negative value?"  We both know
> it can't, but you have to read the entire function to figure that out.
> 
> And that's by definition not intuitive.
> 
> Thanks.

Sure I'll do the cleanup. You guessed correctly why I did that ;)

In the beginning I did a "return len;" instead of "return 1;" and felt a
bit uncomfortable in case we merged a zero length message.

Then I added the !th->fin test inside tcp_try_coalesce()

(my initial patch allowed the fin being set for the tcp_data_queue()
case since tcp_fin() was called anyway)

Thanks