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Date: Thu, 6 Feb 2025 17:41:38 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Joe Damato <jdamato@fastly.com>
Cc: netdev@vger.kernel.org, Donald Hunter <donald.hunter@gmail.com>, "David
 S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Paolo
 Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>, Andrew Lunn
 <andrew+netdev@lunn.ch>, Xuan Zhuo <xuanzhuo@linux.alibaba.com>, Stanislav
 Fomichev <sdf@fomichev.me>, Mina Almasry <almasrymina@google.com>, Daniel
 Jurgens <danielj@nvidia.com>, Martin Karsten <mkarsten@uwaterloo.ca>, open
 list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net-next v3 1/2] netdev-genl: Add an XSK attribute to
 queues
Message-ID: <20250206174138.7de4580d@kernel.org>
In-Reply-To: <Z6Vig04c-a46WScr@LQ3V64L9R2>
References: <20250204191108.161046-1-jdamato@fastly.com>
	<20250204191108.161046-2-jdamato@fastly.com>
	<20250206165746.7cf392b6@kernel.org>
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On Thu, 6 Feb 2025 17:31:47 -0800 Joe Damato wrote:
> > nla_nest_start() can fail, you gotta nul-check the return value.
> > You could possibly add an nla_put_empty_nest() helper in netlink.h
> > to make this less awkward? I think the iouring guys had the same bug  
> 
> Ah, right.
> 
> I'll see what a helper looks like. Feels like maybe overkill?

Yeah, not sure either. Technically nla_nest_end() isn't required here,
but that's not very obvious to a casual reader. So a helper that hides
that fact could be useful:

static inline int nla_put_empty_nest(struct sk_buff *skb, int attrtype)
{
	return nla_nest_start(skb, attrtype) ? 0 : -EMSGSIZE;
}

But totally unsure whether it's worthwhile. Just don't want for someone
to suggest this on v4 and make you respin once again.