Re: [PATCH v3 4/4] brcmfmac: Fix authentication latency caused by OBSS stats survey

[Arend Van Spriel <aspriel@gmail.com>]

On 9/29/2022 3:25 AM, Ian Lin wrote:
> From: Ramesh Rangavittal <ramesh.rangavittal@infineon.com>
> 
> Auto Channel Select feature of HostAP uses dump_survey to fetch
> OBSS statistics. When the device is in the middle of an authentication
> sequence or just at the end of authentication completion, running
> dump_survey would trigger a channel change. The channel change in-turn
> can cause packet loss, resulting in authentication delay. With this change,
> dump_survey won't be run when authentication or association is in progress,
> hence resolving the issue.

It does a bit more than that. It only allows survey when not connected. 
The description above suggests that it is possible when connection is 
completed, but the condition checked below is saying something else.

Regards,
Arend

> Signed-off-by: Ramesh Rangavittal <ramesh.rangavittal@infineon.com>
> Signed-off-by: Chung-Hsien Hsu <chung-hsien.hsu@infineon.com>
> Signed-off-by: Chi-hsien Lin <chi-hsien.lin@infineon.com>
> Signed-off-by: Ian Lin <ian.lin@infineon.com>
> ---
>   drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> index c13c4c559e6e..362d8fd0af4e 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> @@ -7697,6 +7697,12 @@ brcmf_cfg80211_dump_survey(struct wiphy *wiphy, struct net_device *ndev,
>   
>   	brcmf_dbg(TRACE, "Enter: channel idx=%d\n", idx);
>   
> +	/* Do not run survey when VIF in CONNECTING / CONNECTED states */
> +	if ((test_bit(BRCMF_VIF_STATUS_CONNECTING, &ifp->vif->sme_state)) ||
> +	    (test_bit(BRCMF_VIF_STATUS_CONNECTED, &ifp->vif->sme_state))) {
> +		return -EBUSY;
> +	}
> +
>   	band = wiphy->bands[NL80211_BAND_2GHZ];
>   	if (band && idx >= band->n_channels) {
>   		idx -= band->n_channels;