netdev - Re: [PATCH 1/3] net: bgmac: allocate struct bgmac just once & don't copy it

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Message-ID: <8bb6614b-a4af-d435-7db8-616cb1c1a56d@nbd.name>
Date:   Fri, 27 Jan 2017 17:02:33 +0100
From:   Felix Fietkau <nbd@....name>
To:     Rafał Miłecki <zajec5@...il.com>,
        "David S . Miller" <davem@...emloft.net>
Cc:     Jon Mason <jon.mason@...adcom.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Felix Fietkau <nbd@...nwrt.org>, netdev@...r.kernel.org,
        Rafał Miłecki <rafal@...ecki.pl>
Subject: Re: [PATCH 1/3] net: bgmac: allocate struct bgmac just once & don't
 copy it

On 2017-01-27 10:20, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@...ecki.pl>
> 
> To share as much code as possible in bgmac we call alloc_etherdev from
> bgmac.c which is used by both: platform and bcma code. The easiest
> solution was to use it for allocating whole struct bgmac but it doesn't
> work well as we already get early-filled struct bgmac as an argument.
> 
> So far we were solving this by copying received struct into newly
> allocated one. The problem is it means storing 2 allocated structs,
> using only 1 of them and non-shared code not having access to it.
> 
> This patch solves it by using alloc_etherdev to allocate *pointer* for
> the already allocated struct. The only downside of this is we have to be
> careful when using netdev_priv.
> 
> Another solution was to call alloc_etherdev in platform/bcma specific
> code but Jon advised against it due to sharing less code that way.
How does that lead to sharing less code?
I find this pointer indirection rather ugly and uncommon, and I think it
would be much cleaner to split the probe into bgmac_enet_alloc and
bgmac_enet_probe (with bgmac_enet_alloc calling alloc_etherdev and doing
basic setup).

- Felix