From: Kalle Valo <kvalo@kernel.org>
To: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Kang Yang <quic_kangyang@quicinc.com>,
<ath12k@lists.infradead.org>, <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH v6 04/11] wifi: ath12k: add P2P IE in beacon template
Date: Tue, 06 Feb 2024 11:52:35 +0200 [thread overview]
Message-ID: <8734u5syvw.fsf@kernel.org> (raw)
In-Reply-To: <efda8b8e-0257-4779-b0c9-0903164b58c1@quicinc.com> (Jeff Johnson's message of "Mon, 5 Feb 2024 08:35:07 -0800")
Jeff Johnson <quic_jjohnson@quicinc.com> writes:
> On 2/5/2024 8:17 AM, Kalle Valo wrote:
>> Kang Yang <quic_kangyang@quicinc.com> writes:
>>> + 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?
>
> I'm not a fan of typecasting either.
>
> However, the problem here is that from the perspective of
> cfg80211_find_vendor_ie() the buffer is const (not modified in any way
> by the function), but from the perspective of every caller the buffer is
> part of a message that is in RAM.
>
> So you have to decide if you want to change the prototype to remove the
> const from cfg80211_find_vendor_ie() or if you want to keep the current
> semantic to cast away the const.
>
> This is one of the rare cases where I think the typecast is ok.
Makes sense, thanks for the comment.
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
next prev parent reply other threads:[~2024-02-06 9:52 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 4:02 [PATCH v6 00/11] wifi: ath12k: P2P support for WCN7850 Kang Yang
2024-01-30 4:02 ` [PATCH v6 01/11] wifi: ath12k: fix broken structure wmi_vdev_create_cmd Kang Yang
2024-01-30 16:48 ` Jeff Johnson
2024-02-05 15:46 ` Kalle Valo
2024-02-07 15:07 ` Kalle Valo
2024-01-30 4:02 ` [PATCH v6 02/11] wifi: ath12k: fix incorrect logic of calculating vdev_stats_id Kang Yang
2024-01-30 16:51 ` Jeff Johnson
2024-02-05 15:33 ` Kalle Valo
2024-01-30 4:02 ` [PATCH v6 03/11] wifi: ath12k: change interface combination for P2P mode Kang Yang
2024-01-30 16:52 ` Jeff Johnson
2024-01-30 4:02 ` [PATCH v6 04/11] wifi: ath12k: add P2P IE in beacon template Kang Yang
2024-01-30 17:02 ` Jeff Johnson
2024-02-05 16:24 ` Kalle Valo
2024-02-05 16:17 ` Kalle Valo
2024-02-05 16:35 ` Jeff Johnson
2024-02-06 9:52 ` Kalle Valo [this message]
2024-01-30 4:02 ` [PATCH v6 05/11] wifi: ath12k: implement handling of P2P NoA event Kang Yang
2024-01-30 17:14 ` Jeff Johnson
2024-02-02 13:53 ` Kalle Valo
2024-02-02 16:25 ` Jeff Johnson
2024-02-06 2:21 ` Kang Yang
2024-02-06 9:56 ` Kalle Valo
2024-02-06 16:11 ` Kalle Valo
2024-02-06 18:17 ` Kalle Valo
2024-02-07 17:43 ` Jeff Johnson
2024-02-07 4:36 ` Kang Yang
2024-01-30 4:02 ` [PATCH v6 06/11] wifi: ath12k: implement remain on channel for P2P mode Kang Yang
2024-01-30 17:16 ` Jeff Johnson
2024-01-30 4:02 ` [PATCH v6 07/11] wifi: ath12k: change WLAN_SCAN_PARAMS_MAX_IE_LEN from 256 to 512 Kang Yang
2024-01-30 17:19 ` Jeff Johnson
2024-01-30 4:03 ` [PATCH v6 08/11] wifi: ath12k: allow specific mgmt frame tx while vdev is not up Kang Yang
2024-01-30 17:23 ` Jeff Johnson
2024-02-06 16:24 ` Kalle Valo
2024-02-07 4:44 ` Kang Yang
2024-03-07 9:46 ` Kang Yang
2024-01-30 4:03 ` [PATCH v6 09/11] wifi: ath12k: move peer delete after vdev stop of station for WCN7850 Kang Yang
2024-01-30 17:24 ` Jeff Johnson
2024-01-30 4:03 ` [PATCH v6 10/11] wifi: ath12k: designating channel frequency for ROC scan Kang Yang
2024-01-30 17:24 ` Jeff Johnson
2024-01-30 4:03 ` [PATCH v6 11/11] wifi: ath12k: advertise P2P dev support for WCN7850 Kang Yang
2024-01-30 17:25 ` Jeff Johnson
2024-02-05 15:40 ` [PATCH v6 00/11] wifi: ath12k: P2P " Kalle Valo
2024-02-07 6:50 ` Kang Yang
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