From df13cce53a7b28a81460e6bfc4857e9df4956141 Mon Sep 17 00:00:00 2001 From: Helmut Schaa Date: Wed, 24 Feb 2010 14:19:21 +0100 Subject: mac80211: Improve software scan timing The current software scan implemenation in mac80211 returns to the operating channel after each scanned channel. However, in some situations (e.g. no traffic) it would be nicer to scan a few channels in a row to speed up the scan itself. Hence, after scanning a channel, check if we have queued up any tx frames and return to the operating channel in that case. Unfortunately we don't know if the AP has buffered any frames for us. Hence, scan only as many channels in a row as the pm_qos latency and the negotiated listen interval allows us to. Signed-off-by: Helmut Schaa Signed-off-by: John W. Linville --- net/mac80211/scan.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 65 insertions(+), 6 deletions(-) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index b822dce..75a8597 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -14,6 +14,8 @@ #include #include +#include +#include #include #include "ieee80211_i.h" @@ -321,6 +323,7 @@ static int ieee80211_start_sw_scan(struct ieee80211_local *local) ieee80211_offchannel_stop_beaconing(local); + local->leave_oper_channel_time = 0; local->next_scan_state = SCAN_DECISION; local->scan_channel_idx = 0; @@ -425,11 +428,28 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, return rc; } +static unsigned long +ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) +{ + /* + * TODO: channel switching also consumes quite some time, + * add that delay as well to get a better estimation + */ + if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) + return IEEE80211_PASSIVE_CHANNEL_TIME; + return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; +} + static int ieee80211_scan_state_decision(struct ieee80211_local *local, unsigned long *next_delay) { bool associated = false; + bool tx_empty = true; + bool bad_latency; + bool listen_int_exceeded; + unsigned long min_beacon_int = 0; struct ieee80211_sub_if_data *sdata; + struct ieee80211_channel *next_chan; /* if no more bands/channels left, complete scan and advance to the idle state */ if (local->scan_channel_idx >= local->scan_req->n_channels) { @@ -437,7 +457,11 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local, return 1; } - /* check if at least one STA interface is associated */ + /* + * check if at least one STA interface is associated, + * check if at least one STA interface has pending tx frames + * and grab the lowest used beacon interval + */ mutex_lock(&local->iflist_mtx); list_for_each_entry(sdata, &local->interfaces, list) { if (!ieee80211_sdata_running(sdata)) @@ -446,7 +470,16 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local, if (sdata->vif.type == NL80211_IFTYPE_STATION) { if (sdata->u.mgd.associated) { associated = true; - break; + + if (sdata->vif.bss_conf.beacon_int < + min_beacon_int || min_beacon_int == 0) + min_beacon_int = + sdata->vif.bss_conf.beacon_int; + + if (!qdisc_all_tx_empty(sdata->dev)) { + tx_empty = false; + break; + } } } } @@ -455,11 +488,34 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local, if (local->scan_channel) { /* * we're currently scanning a different channel, let's - * switch back to the operating channel now if at least - * one interface is associated. Otherwise just scan the - * next channel + * see if we can scan another channel without interfering + * with the current traffic situation. + * + * Since we don't know if the AP has pending frames for us + * we can only check for our tx queues and use the current + * pm_qos requirements for rx. Hence, if no tx traffic occurs + * at all we will scan as many channels in a row as the pm_qos + * latency allows us to. Additionally we also check for the + * currently negotiated listen interval to prevent losing + * frames unnecessarily. + * + * Otherwise switch back to the operating channel. */ - if (associated) + next_chan = local->scan_req->channels[local->scan_channel_idx]; + + bad_latency = time_after(jiffies + + ieee80211_scan_get_channel_time(next_chan), + local->leave_oper_channel_time + + usecs_to_jiffies(pm_qos_requirement(PM_QOS_NETWORK_LATENCY))); + + listen_int_exceeded = time_after(jiffies + + ieee80211_scan_get_channel_time(next_chan), + local->leave_oper_channel_time + + usecs_to_jiffies(min_beacon_int * 1024) * + local->hw.conf.listen_interval); + + if (associated && ( !tx_empty || bad_latency || + listen_int_exceeded)) local->next_scan_state = SCAN_ENTER_OPER_CHANNEL; else local->next_scan_state = SCAN_SET_CHANNEL; @@ -491,6 +547,9 @@ static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *loca else *next_delay = HZ / 10; + /* remember when we left the operating channel */ + local->leave_oper_channel_time = jiffies; + /* advance to the next channel to be scanned */ local->next_scan_state = SCAN_SET_CHANNEL; } -- cgit v1.1 From b5878a2dc5e7e7f031a52c3e15b571224cb6b540 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 7 Apr 2010 16:48:40 +0200 Subject: mac80211: enhance tracing Enhance tracing by adding tracing for a variety of callbacks that the drivers call, and also for internal calls (currently limited to queue status). This can aid debugging what is going on in mac80211 in interaction with drivers, since we can now see what drivers call and not just what mac80211 calls in the driver. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/scan.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index 75a8597..eb86a5f 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -247,6 +247,8 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) struct ieee80211_local *local = hw_to_local(hw); bool was_hw_scan; + trace_api_scan_completed(local, aborted); + mutex_lock(&local->scan_mtx); /* -- cgit v1.1 From a060bbfe4ee95d115e8f9705a66894ac34e2c475 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 27 Apr 2010 11:59:34 +0200 Subject: mac80211: give virtual interface to hw_scan When scanning, it is somewhat important to scan on the correct virtual interface. All drivers that currently implement hw_scan only support a single virtual interface, but that may change and then we'd want to be ready. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/scan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index eb86a5f..2b1f1f3 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -410,7 +410,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, if (local->ops->hw_scan) { WARN_ON(!ieee80211_prep_hw_scan(local)); - rc = drv_hw_scan(local, local->hw_scan_req); + rc = drv_hw_scan(local, sdata, local->hw_scan_req); } else rc = ieee80211_start_sw_scan(local); @@ -654,7 +654,7 @@ void ieee80211_scan_work(struct work_struct *work) } if (local->hw_scan_req) { - int rc = drv_hw_scan(local, local->hw_scan_req); + int rc = drv_hw_scan(local, sdata, local->hw_scan_req); mutex_unlock(&local->scan_mtx); if (rc) ieee80211_scan_completed(&local->hw, true); -- cgit v1.1 From f0b058b61711ebf5be94d6865ca7b2c259b71d37 Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 28 Apr 2010 15:17:03 +0200 Subject: mac80211: do not wip out old supported rates Use old supported rates, if AP do not provide supported rates information element in a new managment frame. Signed-off-by: Stanislaw Gruszka Signed-off-by: John W. Linville --- net/mac80211/scan.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index 2b1f1f3..a9d4058 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -84,7 +84,7 @@ ieee80211_bss_info_update(struct ieee80211_local *local, { struct cfg80211_bss *cbss; struct ieee80211_bss *bss; - int clen; + int clen, srlen; s32 signal = 0; if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) @@ -113,23 +113,24 @@ ieee80211_bss_info_update(struct ieee80211_local *local, bss->dtim_period = tim_ie->dtim_period; } - bss->supp_rates_len = 0; + /* replace old supported rates if we get new values */ + srlen = 0; if (elems->supp_rates) { - clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len; + clen = IEEE80211_MAX_SUPP_RATES; if (clen > elems->supp_rates_len) clen = elems->supp_rates_len; - memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates, - clen); - bss->supp_rates_len += clen; + memcpy(bss->supp_rates, elems->supp_rates, clen); + srlen += clen; } if (elems->ext_supp_rates) { - clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len; + clen = IEEE80211_MAX_SUPP_RATES - srlen; if (clen > elems->ext_supp_rates_len) clen = elems->ext_supp_rates_len; - memcpy(&bss->supp_rates[bss->supp_rates_len], - elems->ext_supp_rates, clen); - bss->supp_rates_len += clen; + memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen); + srlen += clen; } + if (srlen) + bss->supp_rates_len = srlen; bss->wmm_used = elems->wmm_param || elems->wmm_info; bss->uapsd_supported = is_uapsd_supported(elems); -- cgit v1.1 From be4a4b6a5d2f76393f545a2545fbaa1b65577e13 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 3 May 2010 08:49:48 +0200 Subject: mac80211: improve IBSS scanning When IBSS is fixed to a frequency, it can still scan to try to find the right BSSID. This makes sense if the BSSID isn't also fixed, but it need not scan all channels -- just one is sufficient. Make it do that by moving the scan setup code to ieee80211_request_internal_scan() and include a channel variable setting. Note that this can be further improved to start the IBSS right away if both frequency and BSSID are fixed. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/scan.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index a9d4058..4146512 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -728,10 +728,12 @@ int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, } int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, - const u8 *ssid, u8 ssid_len) + const u8 *ssid, u8 ssid_len, + struct ieee80211_channel *chan) { struct ieee80211_local *local = sdata->local; int ret = -EBUSY; + enum nl80211_band band; mutex_lock(&local->scan_mtx); @@ -739,6 +741,30 @@ int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, if (local->scan_req) goto unlock; + /* fill internal scan request */ + if (!chan) { + int i, nchan = 0; + + for (band = 0; band < IEEE80211_NUM_BANDS; band++) { + if (!local->hw.wiphy->bands[band]) + continue; + for (i = 0; + i < local->hw.wiphy->bands[band]->n_channels; + i++) { + local->int_scan_req->channels[nchan] = + &local->hw.wiphy->bands[band]->channels[i]; + nchan++; + } + } + + local->int_scan_req->n_channels = nchan; + } else { + local->int_scan_req->channels[0] = chan; + local->int_scan_req->n_channels = 1; + } + + local->int_scan_req->ssids = &local->scan_ssid; + local->int_scan_req->n_ssids = 1; memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); local->int_scan_req->ssids[0].ssid_len = ssid_len; -- cgit v1.1