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Subject: Re: [RFCv3 3/3] nl80211: Send large new_wiphy events
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Denis Kenzior <denkenz@gmail.com>, linux-wireless@vger.kernel.org
Date:   Wed, 11 Sep 2019 11:47:53 +0200
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On Fri, 2019-09-06 at 10:43 -0500, Denis Kenzior wrote:
> 
> + *	There are no limits (outside of netlink protocol limits) on
> + *	message sizes that can be sent over the "config2" multicast group. It
> + *	is assumed that applications utilizing "config2" multicast group
> + *	utilize buffers that are inherently large enough or can utilize
> + *	MSG_PEEK/MSG_TRUNC in the netlink transport in order to allocate big
> + *	enough buffers.

I'm not sure I see how the applications could do buffers that are
"inherently" large enough, there's no practical message size limit, is
there (32-bits for the size).

I'd argue this should just say that applications should use large
buffers and still use MSG_PEEK/handle MSG_TRUNC, but I can also edit it
later.

> +	msg = nlmsg_new(alloc_size, GFP_KERNEL);
> +	if (!msg)
> +		goto legacy;
> +
> +	if (WARN_ON(nl80211_send_wiphy(rdev, cmd, msg, 0, 0, 0, &state) < 0)) {
> +		nlmsg_free(msg);
> +		goto legacy;
> +	}
> +
> +	genlmsg_multicast_netns(&nl80211_fam, wiphy_net(&rdev->wiphy), msg, 0,
> +				NL80211_MCGRP_CONFIG2, GFP_KERNEL);
> +
> +legacy:

nit: just use "else" instead of the goto?

johannes