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From: Kalle Valo <kvalo@kernel.org>
To: Kang Yang <quic_kangyang@quicinc.com>
Cc: <ath12k@lists.infradead.org>,  <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH v6 04/11] wifi: ath12k: add P2P IE in beacon template
References: <20240130040303.370590-1-quic_kangyang@quicinc.com>
	<20240130040303.370590-5-quic_kangyang@quicinc.com>
Date: Mon, 05 Feb 2024 18:17:14 +0200
In-Reply-To: <20240130040303.370590-5-quic_kangyang@quicinc.com> (Kang Yang's
	message of "Tue, 30 Jan 2024 12:02:56 +0800")
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Kang Yang <quic_kangyang@quicinc.com> writes:

> P2P Element is a necessary component of P2P protocol communication.
> It contains the Vendor Specific Information Element which includes
> the WFA OUI and an OUI Type indicating P2P.
>
> Add P2P IE in beacon template, and implement WMI interface for it.
>
> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
>
> Signed-off-by: Kang Yang <quic_kangyang@quicinc.com>

[...]

> +static int ath12k_mac_remove_vendor_ie(struct sk_buff *skb, unsigned int oui,
> +				       u8 oui_type, size_t ie_offset)
> +{
> +	size_t len;
> +	const u8 *next;
> +	const u8 *end;
> +	u8 *ie;

Reverse xmas tree and you can merge next and end:

const u8 *next, *end;
size_t len;
u8 *ie;

I changed that in the pending branch.

> +	if (WARN_ON(skb->len < ie_offset))
> +		return -EINVAL;
> +
> +	ie = (u8 *)cfg80211_find_vendor_ie(oui, oui_type,
> +					   skb->data + ie_offset,
> +					   skb->len - ie_offset);

So cfg80211_find_vendor_ie() returns:

static inline const u8 *
cfg80211_find_vendor_ie(unsigned int oui, int oui_type,
			const u8 *ies, unsigned int len)

You are casting away the const here. I see that other drivers do the
same as the assumption is that the pointer points to the same buffer,
but I still don't really like casting away const. Thoughts?

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