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From:   Kalle Valo <kvalo@codeaurora.org>
To:     Wright Feng <Wright.Feng@cypress.com>
Cc:     Arend Van Spriel <arend.vanspriel@broadcom.com>,
        "linux-wireless\@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        "brcm80211-dev-list\@broadcom.com" <brcm80211-dev-list@broadcom.com>,
        brcm80211-dev-list <brcm80211-dev-list@cypress.com>,
        Franky Lin <franky.lin@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Chi-Hsien Lin <Chi-Hsien.Lin@cypress.com>
Subject: Re: [PATCH 1/4] brcmfmac: add change_bss to support AP isolation
References: <20200901063237.15549-1-wright.feng@cypress.com>
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        <0101017467cf4336-e8ed5107-762a-431d-9ef0-a2631dd090be-000000@us-west-2.amazonses.com>
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        <9c5de429-ff6f-cad2-39a7-d5812fd3df09@cypress.com>
Date:   Mon, 7 Sep 2020 15:29:28 +0000
In-Reply-To: <9c5de429-ff6f-cad2-39a7-d5812fd3df09@cypress.com> (Wright Feng's
        message of "Mon, 7 Sep 2020 10:09:17 +0000")
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Wright Feng <Wright.Feng@cypress.com> writes:

>>>>> +brcmf_cfg80211_change_bss(struct wiphy *wiphy, struct net_device *dev,
>>>>> +			  struct bss_parameters *params)
>>>>> +{
>>>>> +	struct brcmf_if *ifp;
>>>>> +	int ret = 0;
>>>>> +	u32 ap_isolate;
>>>>> +
>>>>> +	brcmf_dbg(TRACE, "Enter\n");
>>>>> +	ifp = netdev_priv(dev);
>>>>> +	if (params->ap_isolate >= 0) {
>>>>> +		ap_isolate = (u32)params->ap_isolate;
>>>>> +		ret = brcmf_fil_iovar_int_set(ifp, "ap_isolate", ap_isolate);
>>>>
>>>> Is the cast to u32 really necessary? Please avoid casts as much as
>>>> possible.
>>>
>>> It seems to me. struct bss_parameters::ap_isolate is typed as int. It
>>> is passed to brcmf_fil_iovar_int_set() which requires a u32 (maybe
>>> function name is causing the confusion).
>> 
>> What extra value does this explicit type casting bring here? I don't see
>> it. Implicit type casting would work the same, no?
>
> The value will be -1, 0 or 1.
> I will submit v2 patch that ignores doing iovar if getting 
> params->ap_isolate -1 and removes explicit type casting. Thanks for the 
> comment.

Oh, I didn't realise ap_isolate can be -1 as struct bss_parameters
didn't document that. Can someone submit a patch to fix that?

 * @ap_isolate: do not forward packets between connected stations

-- 
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches