5 files changed, 229 insertions, 216 deletions

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 9fe1f937e0b4..25ff583612ef 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -432,15 +432,7 @@ static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
         printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
                "IBSS networks with same SSID (merge)\n", sdata->dev->name);
 
-        /* XXX maybe racy? */
-        if (sdata->local->scan_req)
-                return;
-
-        memcpy(sdata->local->int_scan_req.ssids[0].ssid,
-               ifibss->ssid, IEEE80211_MAX_SSID_LEN);
-        sdata->local->int_scan_req.ssids[0].ssid_len = ifibss->ssid_len;
-        if (ieee80211_request_scan(sdata, &sdata->local->int_scan_req))
-                ieee80211_scan_failed(sdata->local);
+        ieee80211_request_internal_scan(sdata, ifibss->ssid, ifibss->ssid_len);
 }
 
 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
@@ -553,16 +545,8 @@ static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
                 printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
                        "join\n", sdata->dev->name);
 
-                /* XXX maybe racy? */
-                if (local->scan_req)
-                        return;
-
-                memcpy(local->int_scan_req.ssids[0].ssid,
-                       ifibss->ssid, IEEE80211_MAX_SSID_LEN);
-                local->int_scan_req.ssids[0].ssid_len =
-                        ifibss->ssid_len;
-                if (ieee80211_request_scan(sdata, &local->int_scan_req))
-                        ieee80211_scan_failed(local);
+                ieee80211_request_internal_scan(sdata, ifibss->ssid,
+                                                ifibss->ssid_len);
         } else if (ifibss->state != IEEE80211_IBSS_MLME_JOINED) {
                 int interval = IEEE80211_SCAN_INTERVAL;
 
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 1579bc92c88d..e6fd4bcf1c3c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -659,6 +659,7 @@ struct ieee80211_local {
 
 
         /* Scanning and BSS list */
+        struct mutex scan_mtx;
         bool sw_scanning, hw_scanning;
         struct cfg80211_ssid scan_ssid;
         struct cfg80211_scan_request int_scan_req;
@@ -947,6 +948,8 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata);
 
 /* scan/BSS handling */
 void ieee80211_scan_work(struct work_struct *work);
+int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
+                                    const u8 *ssid, u8 ssid_len);
 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
                            struct cfg80211_scan_request *req);
 int ieee80211_scan_results(struct ieee80211_local *local,
@@ -960,9 +963,6 @@ int ieee80211_sta_set_extra_ie(struct ieee80211_sub_if_data *sdata,
                                const char *ie, size_t len);
 
 void ieee80211_mlme_notify_scan_completed(struct ieee80211_local *local);
-void ieee80211_scan_failed(struct ieee80211_local *local);
-int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
-                         struct cfg80211_scan_request *req);
 struct ieee80211_bss *
 ieee80211_bss_info_update(struct ieee80211_local *local,
                           struct ieee80211_rx_status *rx_status,
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 5ca62ea15079..e00d124e4ef7 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -783,6 +783,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 
         INIT_LIST_HEAD(&local->interfaces);
         mutex_init(&local->iflist_mtx);
+        mutex_init(&local->scan_mtx);
 
         spin_lock_init(&local->key_lock);
 
@@ -1126,6 +1127,7 @@ void ieee80211_free_hw(struct ieee80211_hw *hw)
         struct ieee80211_local *local = hw_to_local(hw);
 
         mutex_destroy(&local->iflist_mtx);
+        mutex_destroy(&local->scan_mtx);
 
         wiphy_free(local->hw.wiphy);
 }
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index f8925ca7c8f0..a2f5e6223059 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2072,19 +2072,15 @@ static int ieee80211_sta_config_auth(struct ieee80211_sub_if_data *sdata)
                 return 0;
         } else {
                 if (ifmgd->assoc_scan_tries < IEEE80211_ASSOC_SCANS_MAX_TRIES) {
+                        u8 ssid_len = 0;
+
+                        if (!(ifmgd->flags & IEEE80211_STA_AUTO_SSID_SEL))
+                                ssid_len = ifmgd->ssid_len;
+
                         ifmgd->assoc_scan_tries++;
-                        /* XXX maybe racy? */
-                        if (local->scan_req)
-                                return -1;
-                        memcpy(local->int_scan_req.ssids[0].ssid,
-                               ifmgd->ssid, IEEE80211_MAX_SSID_LEN);
-                        if (ifmgd->flags & IEEE80211_STA_AUTO_SSID_SEL)
-                                local->int_scan_req.ssids[0].ssid_len = 0;
-                        else
-                                local->int_scan_req.ssids[0].ssid_len = ifmgd->ssid_len;
 
-                        if (ieee80211_start_scan(sdata, &local->int_scan_req))
-                                ieee80211_scan_failed(local);
+                        ieee80211_request_internal_scan(sdata, ifmgd->ssid,
+                                                        ssid_len);
 
                         ifmgd->state = IEEE80211_STA_MLME_AUTHENTICATE;
                         set_bit(IEEE80211_STA_REQ_AUTH, &ifmgd->request);
@@ -2122,14 +2118,8 @@ static void ieee80211_sta_work(struct work_struct *work)
             ifmgd->state != IEEE80211_STA_MLME_AUTHENTICATE &&
             ifmgd->state != IEEE80211_STA_MLME_ASSOCIATE &&
             test_and_clear_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request)) {
-                /*
-                 * The call to ieee80211_start_scan can fail but ieee80211_request_scan
-                 * (which queued ieee80211_sta_work) did not return an error. Thus, call
-                 * ieee80211_scan_failed here if ieee80211_start_scan fails in order to
-                 * notify the scan requester.
-                 */
-                if (ieee80211_start_scan(sdata, local->scan_req))
-                        ieee80211_scan_failed(local);
+                queue_delayed_work(local->hw.workqueue, &local->scan_work,
+                                   round_jiffies_relative(0));
                 return;
         }
 
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index f25b07feabf9..086d21645cbc 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -202,18 +202,6 @@ ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
         return RX_QUEUED;
 }
 
-void ieee80211_scan_failed(struct ieee80211_local *local)
-{
-        if (WARN_ON(!local->scan_req))
-                return;
-
-        /* notify cfg80211 about the failed scan */
-        if (local->scan_req != &local->int_scan_req)
-                cfg80211_scan_done(local->scan_req, true);
-
-        local->scan_req = NULL;
-}
-
 /*
  * inform AP that we will go to sleep so that it will buffer the frames
  * while we scan
@@ -274,29 +262,46 @@ static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata)
         }
 }
 
+static void ieee80211_restore_scan_ies(struct ieee80211_local *local)
+{
+        kfree(local->scan_req->ie);
+        local->scan_req->ie = local->orig_ies;
+        local->scan_req->ie_len = local->orig_ies_len;
+}
+
 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 {
         struct ieee80211_local *local = hw_to_local(hw);
         struct ieee80211_sub_if_data *sdata;
+        bool was_hw_scan;
 
-        if (WARN_ON(!local->hw_scanning && !local->sw_scanning))
-                return;
+        mutex_lock(&local->scan_mtx);
 
-        if (WARN_ON(!local->scan_req))
+        if (WARN_ON(!local->hw_scanning && !local->sw_scanning)) {
+                mutex_unlock(&local->scan_mtx);
                 return;
+        }
 
-        if (local->hw_scanning) {
-                kfree(local->scan_req->ie);
-                local->scan_req->ie = local->orig_ies;
-                local->scan_req->ie_len = local->orig_ies_len;
+        if (WARN_ON(!local->scan_req)) {
+                mutex_unlock(&local->scan_mtx);
+                return;
         }
 
+        if (local->hw_scanning)
+                ieee80211_restore_scan_ies(local);
+
         if (local->scan_req != &local->int_scan_req)
                 cfg80211_scan_done(local->scan_req, aborted);
         local->scan_req = NULL;
 
-        if (local->hw_scanning) {
-                local->hw_scanning = false;
+        was_hw_scan = local->hw_scanning;
+        local->hw_scanning = false;
+        local->sw_scanning = false;
+
+        /* we only have to protect scan_req and hw/sw scan */
+        mutex_unlock(&local->scan_mtx);
+
+        if (was_hw_scan) {
                 /*
                  * Somebody might have requested channel change during scan
                  * that we won't have acted upon, try now. ieee80211_hw_config
@@ -306,7 +311,6 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
                 goto done;
         }
 
-        local->sw_scanning = false;
         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 
         netif_tx_lock_bh(local->mdev);
@@ -354,6 +358,146 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 }
 EXPORT_SYMBOL(ieee80211_scan_completed);
 
+static int ieee80211_start_sw_scan(struct ieee80211_local *local)
+{
+        struct ieee80211_sub_if_data *sdata;
+
+        /*
+         * Hardware/driver doesn't support hw_scan, so use software
+         * scanning instead. First send a nullfunc frame with power save
+         * bit on so that AP will buffer the frames for us while we are not
+         * listening, then send probe requests to each channel and wait for
+         * the responses. After all channels are scanned, tune back to the
+         * original channel and send a nullfunc frame with power save bit
+         * off to trigger the AP to send us all the buffered frames.
+         *
+         * Note that while local->sw_scanning is true everything else but
+         * nullfunc frames and probe requests will be dropped in
+         * ieee80211_tx_h_check_assoc().
+         */
+        if (local->ops->sw_scan_start)
+                local->ops->sw_scan_start(local_to_hw(local));
+
+        mutex_lock(&local->iflist_mtx);
+        list_for_each_entry(sdata, &local->interfaces, list) {
+                if (!netif_running(sdata->dev))
+                        continue;
+
+                /* disable beaconing */
+                if (sdata->vif.type == NL80211_IFTYPE_AP ||
+                    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
+                    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
+                        ieee80211_if_config(sdata,
+                                            IEEE80211_IFCC_BEACON_ENABLED);
+
+                if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+                        if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
+                                netif_tx_stop_all_queues(sdata->dev);
+                                ieee80211_scan_ps_enable(sdata);
+                        }
+                } else
+                        netif_tx_stop_all_queues(sdata->dev);
+        }
+        mutex_unlock(&local->iflist_mtx);
+
+        local->scan_state = SCAN_SET_CHANNEL;
+        local->scan_channel_idx = 0;
+
+        netif_addr_lock_bh(local->mdev);
+        local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
+        local->ops->configure_filter(local_to_hw(local),
+                                     FIF_BCN_PRBRESP_PROMISC,
+                                     &local->filter_flags,
+                                     local->mdev->mc_count,
+                                     local->mdev->mc_list);
+        netif_addr_unlock_bh(local->mdev);
+
+        /* TODO: start scan as soon as all nullfunc frames are ACKed */
+        queue_delayed_work(local->hw.workqueue, &local->scan_work,
+                           IEEE80211_CHANNEL_TIME);
+
+        return 0;
+}
+
+
+static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
+                                  struct cfg80211_scan_request *req)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+        int rc;
+
+        if (local->scan_req)
+                return -EBUSY;
+
+        if (local->ops->hw_scan) {
+                u8 *ies;
+                int ielen;
+
+                ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN +
+                              local->scan_ies_len + req->ie_len, GFP_KERNEL);
+                if (!ies)
+                        return -ENOMEM;
+
+                ielen = ieee80211_build_preq_ies(local, ies,
+                                                 req->ie, req->ie_len);
+                local->orig_ies = req->ie;
+                local->orig_ies_len = req->ie_len;
+                req->ie = ies;
+                req->ie_len = ielen;
+        }
+
+        local->scan_req = req;
+        local->scan_sdata = sdata;
+
+        if (req != &local->int_scan_req &&
+            sdata->vif.type == NL80211_IFTYPE_STATION &&
+            (ifmgd->state == IEEE80211_STA_MLME_DIRECT_PROBE ||
+             ifmgd->state == IEEE80211_STA_MLME_AUTHENTICATE ||
+             ifmgd->state == IEEE80211_STA_MLME_ASSOCIATE)) {
+                /* actually wait for the assoc to finish/time out */
+                set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
+                return 0;
+        }
+
+        if (local->ops->hw_scan)
+                local->hw_scanning = true;
+        else
+                local->sw_scanning = true;
+        /*
+         * Kicking off the scan need not be protected,
+         * only the scan variable stuff, since now
+         * local->scan_req is assigned and other callers
+         * will abort their scan attempts.
+         *
+         * This avoids getting a scan_mtx -> iflist_mtx
+         * dependency, so that the scan completed calls
+         * have more locking freedom.
+         */
+        mutex_unlock(&local->scan_mtx);
+
+        if (local->ops->hw_scan)
+                rc = local->ops->hw_scan(local_to_hw(local),
+                                         local->scan_req);
+        else
+                rc = ieee80211_start_sw_scan(local);
+
+        mutex_lock(&local->scan_mtx);
+
+        if (rc) {
+                if (local->ops->hw_scan) {
+                        local->hw_scanning = false;
+                        ieee80211_restore_scan_ies(local);
+                } else
+                        local->sw_scanning = false;
+
+                local->scan_req = NULL;
+                local->scan_sdata = NULL;
+        }
+
+        return rc;
+}
+
 void ieee80211_scan_work(struct work_struct *work)
 {
         struct ieee80211_local *local =
@@ -363,17 +507,41 @@ void ieee80211_scan_work(struct work_struct *work)
         int skip, i;
         unsigned long next_delay = 0;
 
+        mutex_lock(&local->scan_mtx);
+        if (!sdata || !local->scan_req) {
+                mutex_unlock(&local->scan_mtx);
+                return;
+        }
+
+        if (local->scan_req && !(local->sw_scanning || local->hw_scanning)) {
+                struct cfg80211_scan_request *req = local->scan_req;
+                int rc;
+
+                local->scan_req = NULL;
+
+                rc = __ieee80211_start_scan(sdata, req);
+                mutex_unlock(&local->scan_mtx);
+
+                if (rc)
+                        ieee80211_scan_completed(&local->hw, true);
+                return;
+        }
+
+        mutex_unlock(&local->scan_mtx);
+
         /*
          * Avoid re-scheduling when the sdata is going away.
          */
-        if (!netif_running(sdata->dev))
+        if (!netif_running(sdata->dev)) {
+                ieee80211_scan_completed(&local->hw, true);
                 return;
+        }
 
         switch (local->scan_state) {
         case SCAN_SET_CHANNEL:
                 /* if no more bands/channels left, complete scan */
                 if (local->scan_channel_idx >= local->scan_req->n_channels) {
-                        ieee80211_scan_completed(local_to_hw(local), false);
+                        ieee80211_scan_completed(&local->hw, false);
                         return;
                 }
                 skip = 0;
@@ -422,166 +590,35 @@ void ieee80211_scan_work(struct work_struct *work)
                            next_delay);
 }
 
-
-int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
-                         struct cfg80211_scan_request *req)
+int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
+                           struct cfg80211_scan_request *req)
 {
-        struct ieee80211_local *local = scan_sdata->local;
-        struct ieee80211_sub_if_data *sdata;
-
-        if (!req)
-                return -EINVAL;
-
-        if (local->scan_req && local->scan_req != req)
-                return -EBUSY;
-
-        local->scan_req = req;
-
-        /* MLME-SCAN.request (page 118)  page 144 (11.1.3.1)
-         * BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS
-         * BSSID: MACAddress
-         * SSID
-         * ScanType: ACTIVE, PASSIVE
-         * ProbeDelay: delay (in microseconds) to be used prior to transmitting
-         *    a Probe frame during active scanning
-         * ChannelList
-         * MinChannelTime (>= ProbeDelay), in TU
-         * MaxChannelTime: (>= MinChannelTime), in TU
-         */
-
-         /* MLME-SCAN.confirm
-          * BSSDescriptionSet
-          * ResultCode: SUCCESS, INVALID_PARAMETERS
-         */
-
-        if (local->sw_scanning || local->hw_scanning) {
-                if (local->scan_sdata == scan_sdata)
-                        return 0;
-                return -EBUSY;
-        }
-
-        if (local->ops->hw_scan) {
-                u8 *ies;
-                int rc, ielen;
-
-                ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN +
-                              local->scan_ies_len + req->ie_len, GFP_KERNEL);
-                if (!ies)
-                        return -ENOMEM;
+        int res;
 
-                ielen = ieee80211_build_preq_ies(local, ies,
-                                                 req->ie, req->ie_len);
-                local->orig_ies = req->ie;
-                local->orig_ies_len = req->ie_len;
-                req->ie = ies;
-                req->ie_len = ielen;
-
-                local->hw_scanning = true;
-                rc = local->ops->hw_scan(local_to_hw(local), req);
-                if (rc) {
-                        local->hw_scanning = false;
-                        kfree(ies);
-                        req->ie_len = local->orig_ies_len;
-                        req->ie = local->orig_ies;
-                        return rc;
-                }
-                local->scan_sdata = scan_sdata;
-                return 0;
-        }
+        mutex_lock(&sdata->local->scan_mtx);
+        res = __ieee80211_start_scan(sdata, req);
+        mutex_unlock(&sdata->local->scan_mtx);
 
-        /*
-         * Hardware/driver doesn't support hw_scan, so use software
-         * scanning instead. First send a nullfunc frame with power save
-         * bit on so that AP will buffer the frames for us while we are not
-         * listening, then send probe requests to each channel and wait for
-         * the responses. After all channels are scanned, tune back to the
-         * original channel and send a nullfunc frame with power save bit
-         * off to trigger the AP to send us all the buffered frames.
-         *
-         * Note that while local->sw_scanning is true everything else but
-         * nullfunc frames and probe requests will be dropped in
-         * ieee80211_tx_h_check_assoc().
-         */
-        local->sw_scanning = true;
-        if (local->ops->sw_scan_start)
-                local->ops->sw_scan_start(local_to_hw(local));
-
-        mutex_lock(&local->iflist_mtx);
-        list_for_each_entry(sdata, &local->interfaces, list) {
-                if (!netif_running(sdata->dev))
-                        continue;
-
-                /* disable beaconing */
-                if (sdata->vif.type == NL80211_IFTYPE_AP ||
-                    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
-                    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
-                        ieee80211_if_config(sdata,
-                                            IEEE80211_IFCC_BEACON_ENABLED);
-
-                if (sdata->vif.type == NL80211_IFTYPE_STATION) {
-                        if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
-                                netif_tx_stop_all_queues(sdata->dev);
-                                ieee80211_scan_ps_enable(sdata);
-                        }
-                } else
-                        netif_tx_stop_all_queues(sdata->dev);
-        }
-        mutex_unlock(&local->iflist_mtx);
-
-        local->scan_state = SCAN_SET_CHANNEL;
-        local->scan_channel_idx = 0;
-        local->scan_sdata = scan_sdata;
-        local->scan_req = req;
-
-        netif_addr_lock_bh(local->mdev);
-        local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
-        local->ops->configure_filter(local_to_hw(local),
-                                     FIF_BCN_PRBRESP_PROMISC,
-                                     &local->filter_flags,
-                                     local->mdev->mc_count,
-                                     local->mdev->mc_list);
-        netif_addr_unlock_bh(local->mdev);
-
-        /* TODO: start scan as soon as all nullfunc frames are ACKed */
-        queue_delayed_work(local->hw.workqueue, &local->scan_work,
-                           IEEE80211_CHANNEL_TIME);
-
-        return 0;
+        return res;
 }
 
-
-int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
-                           struct cfg80211_scan_request *req)
+int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
+                                    const u8 *ssid, u8 ssid_len)
 {
         struct ieee80211_local *local = sdata->local;
-        struct ieee80211_if_managed *ifmgd;
-
-        if (!req)
-                return -EINVAL;
-
-        if (local->scan_req && local->scan_req != req)
-                return -EBUSY;
-
-        local->scan_req = req;
+        int ret = -EBUSY;
 
-        if (sdata->vif.type != NL80211_IFTYPE_STATION)
-                return ieee80211_start_scan(sdata, req);
+        mutex_lock(&local->scan_mtx);
 
-        /*
-         * STA has a state machine that might need to defer scanning
-         * while it's trying to associate/authenticate, therefore we
-         * queue it up to the state machine in that case.
-         */
+        /* busy scanning */
+        if (local->scan_req)
+                goto unlock;
 
-        if (local->sw_scanning || local->hw_scanning) {
-                if (local->scan_sdata == sdata)
-                        return 0;
-                return -EBUSY;
-        }
-
-        ifmgd = &sdata->u.mgd;
-        set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
-        queue_work(local->hw.workqueue, &ifmgd->work);
+        memcpy(local->int_scan_req.ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
+        local->int_scan_req.ssids[0].ssid_len = ssid_len;
 
-        return 0;
+        ret = __ieee80211_start_scan(sdata, &sdata->local->int_scan_req);
+ unlock:
+        mutex_unlock(&local->scan_mtx);
+        return ret;
 }