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mac80211: fix PS-poll response, race 

When a station queries us for a PS-poll response, we wrongly
queue the frame on the virtual interface's queue rather than
the pending queue.

Additionally, fix a race condition where we could potentially
send multiple frames to the sleeping station due to using a
station flag rather than a packet flag. When converting to a
packet flag, we can also convert p54 and remove the filter
clearing we added for it.

(Also remove a now dead function)

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Reported-by: Bob Copeland <me@bobcopeland.com>
Tested-by: Bob Copeland <me@bobcopeland.com>
Cc: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg 2009-07-24 13:23:09 +02:00 committed by John W. Linville
parent 91a3bd7615
commit 3fa52056f3
5 changed files with 12 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/wireless/p54/txrx.c
View File

@ -614,7 +614,7 @@ static void p54_tx_80211_header(struct p54_common *priv, struct sk_buff *skb,
if (info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ)
*flags |= P54_HDR_FLAG_DATA_OUT_SEQNR;
if (info->flags & IEEE80211_TX_CTL_CLEAR_PS_FILT)
if (info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE)
*flags |= P54_HDR_FLAG_DATA_OUT_NOCANCEL;
*queue = skb_get_queue_mapping(skb) + P54_QUEUE_DATA;

4
include/net/mac80211.h
View File

@ -243,6 +243,9 @@ struct ieee80211_bss_conf {
* used to indicate that a frame was already retried due to PS
* @IEEE80211_TX_INTFL_DONT_ENCRYPT: completely internal to mac80211,
* used to indicate frame should not be encrypted
* @IEEE80211_TX_CTL_PSPOLL_RESPONSE: (internal?)
* This frame is a response to a PS-poll frame and should be sent
* although the station is in powersave mode.
*/
enum mac80211_tx_control_flags {
IEEE80211_TX_CTL_REQ_TX_STATUS = BIT(0),
@ -262,6 +265,7 @@ enum mac80211_tx_control_flags {
IEEE80211_TX_INTFL_NEED_TXPROCESSING = BIT(14),
IEEE80211_TX_INTFL_RETRIED = BIT(15),
IEEE80211_TX_INTFL_DONT_ENCRYPT = BIT(16),
IEEE80211_TX_CTL_PSPOLL_RESPONSE = BIT(17),
};
/**

11
net/mac80211/rx.c
View File

@ -783,7 +783,7 @@ static void ap_sta_ps_start(struct sta_info *sta)
struct ieee80211_local *local = sdata->local;
atomic_inc(&sdata->bss->num_sta_ps);
set_and_clear_sta_flags(sta, WLAN_STA_PS, WLAN_STA_PSPOLL);
set_sta_flags(sta, WLAN_STA_PS);
drv_sta_notify(local, &sdata->vif, STA_NOTIFY_SLEEP, &sta->sta);
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "%s: STA %pM aid %d enters power save mode\n",
@ -799,7 +799,7 @@ static int ap_sta_ps_end(struct sta_info *sta)
atomic_dec(&sdata->bss->num_sta_ps);
clear_sta_flags(sta, WLAN_STA_PS | WLAN_STA_PSPOLL);
clear_sta_flags(sta, WLAN_STA_PS);
drv_sta_notify(local, &sdata->vif, STA_NOTIFY_AWAKE, &sta->sta);
if (!skb_queue_empty(&sta->ps_tx_buf))
@ -1117,14 +1117,15 @@ ieee80211_rx_h_ps_poll(struct ieee80211_rx_data *rx)
skb_queue_empty(&rx->sta->ps_tx_buf);
if (skb) {
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr =
(struct ieee80211_hdr *) skb->data;
/*
* Tell TX path to send one frame even though the STA may
* Tell TX path to send this frame even though the STA may
* still remain is PS mode after this frame exchange.
*/
set_sta_flags(rx->sta, WLAN_STA_PSPOLL);
info->flags |= IEEE80211_TX_CTL_PSPOLL_RESPONSE;
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "STA %pM aid %d: PS Poll (entries after %d)\n",
@ -1139,7 +1140,7 @@ ieee80211_rx_h_ps_poll(struct ieee80211_rx_data *rx)
else
hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREDATA);
dev_queue_xmit(skb);
ieee80211_add_pending_skb(rx->local, skb);
if (no_pending_pkts)
sta_info_clear_tim_bit(rx->sta);

13
net/mac80211/sta_info.h
View File

@ -30,7 +30,6 @@
* @WLAN_STA_ASSOC_AP: We're associated to that station, it is an AP.
* @WLAN_STA_WME: Station is a QoS-STA.
* @WLAN_STA_WDS: Station is one of our WDS peers.
* @WLAN_STA_PSPOLL: Station has just PS-polled us.
* @WLAN_STA_CLEAR_PS_FILT: Clear PS filter in hardware (using the
* IEEE80211_TX_CTL_CLEAR_PS_FILT control flag) when the next
* frame to this station is transmitted.
@ -47,7 +46,6 @@ enum ieee80211_sta_info_flags {
WLAN_STA_ASSOC_AP = 1<<5,
WLAN_STA_WME = 1<<6,
WLAN_STA_WDS = 1<<7,
WLAN_STA_PSPOLL = 1<<8,
WLAN_STA_CLEAR_PS_FILT = 1<<9,
WLAN_STA_MFP = 1<<10,
WLAN_STA_SUSPEND = 1<<11
@ -359,17 +357,6 @@ static inline void clear_sta_flags(struct sta_info *sta, const u32 flags)
spin_unlock_irqrestore(&sta->flaglock, irqfl);
}
static inline void set_and_clear_sta_flags(struct sta_info *sta,
const u32 set, const u32 clear)
{
unsigned long irqfl;
spin_lock_irqsave(&sta->flaglock, irqfl);
sta->flags |= set;
sta->flags &= ~clear;
spin_unlock_irqrestore(&sta->flaglock, irqfl);
}
static inline u32 test_sta_flags(struct sta_info *sta, const u32 flags)
{
u32 ret;

19
net/mac80211/tx.c
View File

@ -373,7 +373,7 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
staflags = get_sta_flags(sta);
if (unlikely((staflags & WLAN_STA_PS) &&
!(staflags & WLAN_STA_PSPOLL))) {
!(info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE))) {
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "STA %pM aid %d: PS buffer (entries "
"before %d)\n",
@ -412,24 +412,7 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
sta->sta.addr);
}
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
if (test_and_clear_sta_flags(sta, WLAN_STA_PSPOLL)) {
/*
* The sleeping station with pending data is now snoozing.
* It queried us for its buffered frames and will go back
* to deep sleep once it got everything.
*
* inform the driver, in case the hardware does powersave
* frame filtering and keeps a station blacklist on its own
* (e.g: p54), so that frames can be delivered unimpeded.
*
* Note: It should be safe to disable the filter now.
* As, it is really unlikely that we still have any pending
* frame for this station in the hw's buffers/fifos left,
* that is not rejected with a unsuccessful tx_status yet.
*/
info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
}
return TX_CONTINUE;
}