Re: [PATCH v2 3/4] station: knownnetworks: limit quick scans to 5 freqs per network

[Denis Kenzior <denkenz@gmail.com>]

Hi James,

On 1/24/24 07:40, James Prestwood wrote:
> In very large network deployments there could be a vast amount of APs
> which could create a large known frequency list after some time once
> all the APs are seen in scan results. This then increases the quick
> scan time significantly, in the very worst case (but unlikely) just
> as long as a full scan.
> 
> To help with this support in knownnetworks was added to limit the
> number of frequencies per network. Station will now only get 5
> recent frequencies per network making the maximum frequencies 25
> in the worst case (~2.5s scan).
> 
> The magic values are now defines, and the recent roam frequencies
> was also changed to use this define as well.

Yep, I like it.

> ---
>   src/knownnetworks.c |  9 ++++++---
>   src/knownnetworks.h |  3 ++-
>   src/station.c       | 10 ++++++++--
>   3 files changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/src/knownnetworks.c b/src/knownnetworks.c
> index 6e549e02..fe0fce09 100644
> --- a/src/knownnetworks.c
> +++ b/src/knownnetworks.c
> @@ -518,7 +518,8 @@ struct network_info *known_networks_find(const char *ssid,
>   }
>   
>   struct scan_freq_set *known_networks_get_recent_frequencies(
> -						uint8_t num_networks_tosearch)
> +						uint8_t num_networks_tosearch,
> +						uint8_t freqs_per_network)
>   {
>   	/*
>   	 * This search function assumes that the known networks are always
> @@ -530,7 +531,7 @@ struct scan_freq_set *known_networks_get_recent_frequencies(
>   	const struct l_queue_entry *freq_entry;
>   	struct scan_freq_set *set;
>   
> -	if (!num_networks_tosearch)
> +	if (!num_networks_tosearch || !freqs_per_network)
>   		return NULL;
>   
>   	set = scan_freq_set_new();
> @@ -540,10 +541,12 @@ struct scan_freq_set *known_networks_get_recent_frequencies(
>   				network_entry = network_entry->next,
>   						num_networks_tosearch--) {
>   		const struct network_info *network = network_entry->data;
> +		uint8_t freqs_found = 0;
>   
>   		for (freq_entry = l_queue_get_entries(
>   						network->known_frequencies);
> -				freq_entry; freq_entry = freq_entry->next) {
> +				freq_entry && freqs_found < freqs_per_network;
> +				freq_entry = freq_entry->next, freqs_found++) {

This is getting a bit unreadable.  Maybe a while loop makes this look better?

freq_entry = l_queue_get_entries();

while (freq_entry && freqs_found < freq_per_network) {
	...
	freqs_found += 1;
	freq_entry = freq_entry->next;
}

>   			const struct known_frequency *known_freq =
>   							freq_entry->data;
>   

Regards,
-Denis