Re: [PATCH net-next v2 03/10] net: ppp: Remove unnecessary (void*) conversions

[yunchuan]

On 2023/7/12 01:50, Simon Horman wrote:
> > -	struct sock *sk = (struct sock *)chan->private;
> > +	struct sock *sk = chan->private;
> >   	struct pppox_sock *po = pppox_sk(sk);
> >   	struct net_device *dev = po->pppoe_dev;
> Hi,
>
> Please don't break reverse xmas tree ordering - longest line to shortest -
> of local variable declarations in Networking code.

Hi,

This can't be reversed because it depends on the first declaration.
Should I change it like this?

-	struct sock *sk = (struct sock *)chan->private;
- 	struct pppox_sock *po = pppox_sk(sk);
+	struct pppox_sock *po = pppox_sk(chan->private);
 	struct net_device *dev = po->pppoe_dev;
+	struct sock *sk = chan->private;

But this seems to be bad. As the advice of Andrew[1] and Dan[2]:

"

When dealing with existing broken reverse Christmas tree, please don't
make it worse with a change. But actually fixing it should be in a
different patch.

We want patches to be obviously correct. By removing the cast and
moving variables around, it is less obvious it is correct, than having
two patches.

"

Wu Yunchuan

[1] 
https://lore.kernel.org/all/23e98085-8f07-4ee2-8487-8e3b439b69f4@xxxxxxx/
[2] 
https://lore.kernel.org/all/45519aec-6ec8-49e5-b5b2-1b52d336288c@kadam.mountain/
>