iwlwifi: mvm: Refactor and fix max probe len computation

Move iwl_mvm_max_scan_ie_len function to scan.c and fix the
implementation to conform with the LMAC scan API.
Since the correct implementation would leave us with unacceptably
tiny probes, add a workaround which returns a larger value.
In current implementation it's possible that unified_scan_lmac and
unified_sched_scan_lmac would return -ENOBUFS.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index 412a8a0..c7a73c6 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -279,14 +279,6 @@ static void iwl_mvm_reset_phy_ctxts(struct iwl_mvm *mvm)
        }
 }
 
-static int iwl_mvm_max_scan_ie_len(struct iwl_mvm *mvm)
-{
-       /* we create the 802.11 header and SSID element */
-       if (mvm->fw->ucode_capa.flags & IWL_UCODE_TLV_FLAGS_NO_BASIC_SSID)
-               return mvm->fw->ucode_capa.max_probe_length - 24 - 2;
-       return mvm->fw->ucode_capa.max_probe_length - 24 - 34;
-}
-
 int iwl_mvm_mac_setup_register(struct iwl_mvm *mvm)
 {
        struct ieee80211_hw *hw = mvm->hw;
@@ -379,7 +371,7 @@ int iwl_mvm_mac_setup_register(struct iwl_mvm *mvm)
 
        iwl_mvm_reset_phy_ctxts(mvm);
 
-       hw->wiphy->max_scan_ie_len = iwl_mvm_max_scan_ie_len(mvm);
+       hw->wiphy->max_scan_ie_len = iwl_mvm_max_scan_ie_len(mvm, false);
 
        hw->wiphy->max_scan_ssids = PROBE_OPTION_MAX;
 

diff --git a/drivers/net/wireless/iwlwifi/mvm/mvm.h b/drivers/net/wireless/iwlwifi/mvm/mvm.h
index 7d0194b..b153ced 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/iwlwifi/mvm/mvm.h
@@ -935,6 +935,7 @@ int iwl_mvm_rx_scan_response(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 int iwl_mvm_rx_scan_complete(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
                             struct iwl_device_cmd *cmd);
 int iwl_mvm_cancel_scan(struct iwl_mvm *mvm);
+int iwl_mvm_max_scan_ie_len(struct iwl_mvm *mvm, bool is_sched_scan);
 
 /* Scheduled scan */
 int iwl_mvm_rx_scan_offload_complete_notif(struct iwl_mvm *mvm,

diff --git a/drivers/net/wireless/iwlwifi/mvm/scan.c b/drivers/net/wireless/iwlwifi/mvm/scan.c
index 076fe1b..cb85e63 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/scan.c
+++ b/drivers/net/wireless/iwlwifi/mvm/scan.c
@@ -346,6 +346,48 @@ static inline bool iwl_mvm_rrm_scan_needed(struct iwl_mvm *mvm)
               IWL_UCODE_TLV_CAPA_DS_PARAM_SET_IE_SUPPORT;
 }
 
+static int iwl_mvm_max_scan_ie_fw_cmd_room(struct iwl_mvm *mvm,
+                                          bool is_sched_scan)
+{
+       int max_probe_len;
+
+       if (mvm->fw->ucode_capa.api[0] & IWL_UCODE_TLV_API_LMAC_SCAN)
+               max_probe_len = SCAN_OFFLOAD_PROBE_REQ_SIZE;
+       else
+               max_probe_len = mvm->fw->ucode_capa.max_probe_length;
+
+       /* we create the 802.11 header and SSID element */
+       max_probe_len -= 24 + 2;
+
+       /* basic ssid is added only for hw_scan with and old api */
+       if (!(mvm->fw->ucode_capa.flags & IWL_UCODE_TLV_FLAGS_NO_BASIC_SSID) &&
+           !(mvm->fw->ucode_capa.api[0] & IWL_UCODE_TLV_API_LMAC_SCAN) &&
+           !is_sched_scan)
+               max_probe_len -= 32;
+
+       return max_probe_len;
+}
+
+int iwl_mvm_max_scan_ie_len(struct iwl_mvm *mvm, bool is_sched_scan)
+{
+       int max_ie_len = iwl_mvm_max_scan_ie_fw_cmd_room(mvm, is_sched_scan);
+
+       if (!(mvm->fw->ucode_capa.api[0] & IWL_UCODE_TLV_API_LMAC_SCAN))
+               return max_ie_len;
+
+       /* TODO: [BUG] This function should return the maximum allowed size of
+        * scan IEs, however the LMAC scan api contains both 2GHZ and 5GHZ IEs
+        * in the same command. So the correct implementation of this function
+        * is just iwl_mvm_max_scan_ie_fw_cmd_room() / 2. Currently the scan
+        * command has only 512 bytes and it would leave us with about 240
+        * bytes for scan IEs, which is clearly not enough. So meanwhile
+        * we will report an incorrect value. This may result in a failure to
+        * issue a scan in unified_scan_lmac and unified_sched_scan_lmac
+        * functions with -ENOBUFS, if a large enough probe will be provided.
+        */
+       return max_ie_len;
+}
+
 int iwl_mvm_scan_request(struct iwl_mvm *mvm,
                         struct ieee80211_vif *vif,
                         struct cfg80211_scan_request *req)
@@ -1191,13 +1233,12 @@ int iwl_mvm_unified_scan_lmac(struct iwl_mvm *mvm,
        if (WARN_ON(mvm->scan_cmd == NULL))
                return -ENOMEM;
 
-       if (WARN_ON_ONCE(req->req.n_ssids > PROBE_OPTION_MAX ||
-                        req->ies.common_ie_len + req->ies.len[0] +
-                               req->ies.len[1] + 24 + 2 >
-                                       SCAN_OFFLOAD_PROBE_REQ_SIZE ||
-                        req->req.n_channels >
-                               mvm->fw->ucode_capa.n_scan_channels))
-               return -1;
+       if (req->req.n_ssids > PROBE_OPTION_MAX ||
+           req->ies.common_ie_len + req->ies.len[NL80211_BAND_2GHZ] +
+           req->ies.len[NL80211_BAND_5GHZ] >
+               iwl_mvm_max_scan_ie_fw_cmd_room(mvm, false) ||
+           req->req.n_channels > mvm->fw->ucode_capa.n_scan_channels)
+               return -ENOBUFS;
 
        mvm->scan_status = IWL_MVM_SCAN_OS;
 
@@ -1285,10 +1326,11 @@ int iwl_mvm_unified_sched_scan_lmac(struct iwl_mvm *mvm,
        if (WARN_ON(mvm->scan_cmd == NULL))
                return -ENOMEM;
 
-       if (WARN_ON_ONCE(req->n_ssids > PROBE_OPTION_MAX ||
-                        ies->common_ie_len + ies->len[0] + ies->len[1] + 24 + 2
-                               > SCAN_OFFLOAD_PROBE_REQ_SIZE ||
-                        req->n_channels > mvm->fw->ucode_capa.n_scan_channels))
+       if (req->n_ssids > PROBE_OPTION_MAX ||
+           ies->common_ie_len + ies->len[NL80211_BAND_2GHZ] +
+           ies->len[NL80211_BAND_5GHZ] >
+               iwl_mvm_max_scan_ie_fw_cmd_room(mvm, true) ||
+           req->n_channels > mvm->fw->ucode_capa.n_scan_channels)
                return -ENOBUFS;
 
        iwl_mvm_scan_calc_params(mvm, vif, req->n_ssids, 0, &params);