From: Helmut Schaa <helmut.schaa@googlemail.com>
To: greearb@candelatech.com
Cc: linux-wireless@vger.kernel.org
Subject: Re: [PATCH] mac80211: Optimize scans on current operating channel.
Date: Fri, 21 Jan 2011 09:19:13 +0100 [thread overview]
Message-ID: <201101210919.13673.helmut.schaa@googlemail.com> (raw)
In-Reply-To: <1295588389-10860-1-git-send-email-greearb@candelatech.com>
Am Freitag, 21. Januar 2011 schrieb greearb@candelatech.com:
> From: Ben Greear <greearb@candelatech.com>
>
> This should decrease un-necessary flushes, on/off channel work,
> and channel changes in cases where the only scanned channel is
> the current operating channel.
>
> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
> :100644 100644 c47d7c0... 59fe5e7... M net/mac80211/ieee80211_i.h
> :100644 100644 1236710... e6de0e7... M net/mac80211/rx.c
> :100644 100644 3e660db... 5804fbb... M net/mac80211/scan.c
> net/mac80211/ieee80211_i.h | 5 +++++
> net/mac80211/rx.c | 11 ++++++++---
> net/mac80211/scan.c | 41 +++++++++++++++++++++++++----------------
> 3 files changed, 38 insertions(+), 19 deletions(-)
>
> diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
> index c47d7c0..59fe5e7 100644
> --- a/net/mac80211/ieee80211_i.h
> +++ b/net/mac80211/ieee80211_i.h
> @@ -660,6 +660,10 @@ struct tpt_led_trigger {
> * that the scan completed.
> * @SCAN_ABORTED: Set for our scan work function when the driver reported
> * a scan complete for an aborted scan.
> + * @SCAN_LEFT_OPER_CHANNEL: Set this flag if the scan process leaves the
> + * operating channel at any time. If scanning ONLY the current operating
> + * channel this flag should not be set, and this will allow fewer
> + * offchannel changes.
> */
> enum {
> SCAN_SW_SCANNING,
> @@ -667,6 +671,7 @@ enum {
> SCAN_OFF_CHANNEL,
> SCAN_COMPLETED,
> SCAN_ABORTED,
> + SCAN_LEFT_OPER_CHANNEL,
> };
>
> /**
> diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
> index 1236710..e6de0e7 100644
> --- a/net/mac80211/rx.c
> +++ b/net/mac80211/rx.c
> @@ -388,6 +388,7 @@ ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
> struct ieee80211_local *local = rx->local;
> struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
> struct sk_buff *skb = rx->skb;
> + int ret;
>
> if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN)))
> return RX_CONTINUE;
> @@ -396,10 +397,14 @@ ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
> return ieee80211_scan_rx(rx->sdata, skb);
>
> if (test_bit(SCAN_SW_SCANNING, &local->scanning)) {
> - /* drop all the other packets during a software scan anyway */
> - if (ieee80211_scan_rx(rx->sdata, skb) != RX_QUEUED)
> + ret = ieee80211_scan_rx(rx->sdata, skb);
> + /* drop all the other packets while scanning off channel */
> + if (ret != RX_QUEUED &&
> + test_bit(SCAN_OFF_CHANNEL, &local->scanning)) {
> dev_kfree_skb(skb);
> - return RX_QUEUED;
> + return RX_QUEUED;
> + }
> + return ret;
> }
>
> /* scanning finished during invoking of handlers */
> diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
> index 3e660db..5804fbb 100644
> --- a/net/mac80211/scan.c
> +++ b/net/mac80211/scan.c
> @@ -293,11 +293,14 @@ static void __ieee80211_scan_completed_finish(struct ieee80211_hw *hw,
> {
> struct ieee80211_local *local = hw_to_local(hw);
>
> - ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
> + if (test_bit(SCAN_LEFT_OPER_CHANNEL, &local->scanning) || was_hw_scan)
> + ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
> +
Why not
if (!test_bit(SCAN_OFF_CHANNEL, &local->scanning) || was_hw_scan)
instead? If the last scanned channel was a off channel scan this bit will
still be set. And that way you don't need this new flag.
> if (!was_hw_scan) {
> ieee80211_configure_filter(local);
> drv_sw_scan_complete(local);
> - ieee80211_offchannel_return(local, true);
> + if (test_bit(SCAN_LEFT_OPER_CHANNEL, &local->scanning))
> + ieee80211_offchannel_return(local, true);
Same here.
> }
>
> mutex_lock(&local->mtx);
> @@ -397,13 +400,10 @@ static int ieee80211_start_sw_scan(struct ieee80211_local *local)
>
> drv_sw_scan_start(local);
>
> - ieee80211_offchannel_stop_beaconing(local);
> -
You could split that out in a second patch since this change might also make sense
on its own.
> local->leave_oper_channel_time = 0;
> local->next_scan_state = SCAN_DECISION;
> local->scan_channel_idx = 0;
> -
> - drv_flush(local, false);
> + __clear_bit(SCAN_LEFT_OPER_CHANNEL, &local->scanning);
>
> ieee80211_configure_filter(local);
>
> @@ -543,7 +543,18 @@ static void ieee80211_scan_state_decision(struct ieee80211_local *local,
> }
> mutex_unlock(&local->iflist_mtx);
>
> - if (local->scan_channel) {
> + next_chan = local->scan_req->channels[local->scan_channel_idx];
> +
> + if (local->oper_channel == local->hw.conf.channel) {
Isn't that equivalent to !test_bit(SCAN_OFF_CHANNEL, ...)?
> + if (next_chan == local->oper_channel)
> + local->next_scan_state = SCAN_SET_CHANNEL;
> + else
> + /*
> + * we're on the operating channel currently, let's
> + * leave that channel now to scan another one
> + */
> + local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
> + } else {
> /*
> * we're currently scanning a different channel, let's
> * see if we can scan another channel without interfering
> @@ -559,7 +570,6 @@ static void ieee80211_scan_state_decision(struct ieee80211_local *local,
> *
> * Otherwise switch back to the operating channel.
> */
> - next_chan = local->scan_req->channels[local->scan_channel_idx];
>
> bad_latency = time_after(jiffies +
> ieee80211_scan_get_channel_time(next_chan),
> @@ -577,12 +587,6 @@ static void ieee80211_scan_state_decision(struct ieee80211_local *local,
> local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
> else
> local->next_scan_state = SCAN_SET_CHANNEL;
> - } else {
> - /*
> - * we're on the operating channel currently, let's
> - * leave that channel now to scan another one
> - */
> - local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
> }
>
> *next_delay = 0;
> @@ -591,9 +595,12 @@ static void ieee80211_scan_state_decision(struct ieee80211_local *local,
> static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
> unsigned long *next_delay)
> {
> + ieee80211_offchannel_stop_beaconing(local);
> +
> ieee80211_offchannel_stop_station(local);
>
> __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
> + __set_bit(SCAN_LEFT_OPER_CHANNEL, &local->scanning);
>
> /*
> * What if the nullfunc frames didn't arrive?
> @@ -640,8 +647,10 @@ static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
> chan = local->scan_req->channels[local->scan_channel_idx];
>
> local->scan_channel = chan;
> - if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
> - skip = 1;
> +
> + if (chan != local->hw.conf.channel)
> + if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
> + skip = 1;
>
> /* advance state machine to next channel/band */
> local->scan_channel_idx++;
>
next prev parent reply other threads:[~2011-01-21 8:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-21 5:39 [PATCH] mac80211: Optimize scans on current operating channel greearb
2011-01-21 8:19 ` Helmut Schaa [this message]
2011-01-21 13:59 ` Ben Greear
2011-01-21 14:27 ` Ben Greear
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