linux-kernel - [PATCH 3.16 046/192] iwlwifi: mvm: fix the recovery flow while connecting

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Message-ID: <lsq.1507553064.997518943@decadent.org.uk>
Date:   Mon, 09 Oct 2017 13:44:24 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Luca Coelho" <luciano.coelho@...el.com>,
        "Emmanuel Grumbach" <emmanuel.grumbach@...el.com>
Subject: [PATCH 3.16 046/192] iwlwifi: mvm: fix the recovery flow while
 connecting

3.16.49-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Emmanuel Grumbach <emmanuel.grumbach@...el.com>

commit 6b28f9784c394f0692e160f81b07c82cb64af160 upstream.

In BSS mode in the disconnection flow, mac80211 removes
the AP station before the vif is set to unassociated.
Our firmware wants it the other way around: first set
the vif as unassociated, and then remove the AP station.

In order to bridge between those two different behaviors,
iwlmvm doesn't remove the station from the firmware when
mac80211 removes it, but only after the vif is set to
unassociated. The implementation is in
iwl_mvm_bss_info_changed_station:

if (assoc state was modified && mvmvif->ap_sta_id is VALID
    && assoc state is now UNASSC)
	remove_the_station_from_the_firmware()

During the recovery flow, mac80211 re-adds the AP station
and then reconfigures the vif. Since the vif is not
associated, and then, we enter the if above (which was
intended to be taken in the disconnection flow only) and
remove the station we just added. This defeats the
recovery flow.

Fix this by not removing the AP station in this flow if
we are in recovery flow.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@...el.com>
Signed-off-by: Luca Coelho <luciano.coelho@...el.com>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/net/wireless/iwlwifi/mvm/mac80211.c | 32 ++++++++++++++++++-----
 1 file changed, 25 insertions(+), 7 deletions(-)

--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -1315,14 +1315,32 @@ static void iwl_mvm_bss_info_changed_sta
 			WARN_ONCE(iwl_mvm_sf_update(mvm, vif, false),
 				  "Failed to update SF upon disassociation\n");
 
-			/* remove AP station now that the MAC is unassoc */
-			ret = iwl_mvm_rm_sta_id(mvm, vif, mvmvif->ap_sta_id);
-			if (ret)
-				IWL_ERR(mvm, "failed to remove AP station\n");
+			/*
+			 * If we get an assert during the connection (after the
+			 * station has been added, but before the vif is set
+			 * to associated), mac80211 will re-add the station and
+			 * then configure the vif. Since the vif is not
+			 * associated, we would remove the station here and
+			 * this would fail the recovery.
+			 */
+			if (!test_bit(IWL_MVM_STATUS_IN_HW_RESTART,
+				      &mvm->status)) {
+				/*
+				 * Remove AP station now that
+				 * the MAC is unassoc
+				 */
+				ret = iwl_mvm_rm_sta_id(mvm, vif,
+							mvmvif->ap_sta_id);
+				if (ret)
+					IWL_ERR(mvm,
+						"failed to remove AP station\n");
+
+				if (mvm->d0i3_ap_sta_id == mvmvif->ap_sta_id)
+					mvm->d0i3_ap_sta_id =
+						IWL_MVM_STATION_COUNT;
+				mvmvif->ap_sta_id = IWL_MVM_STATION_COUNT;
+			}
 
-			if (mvm->d0i3_ap_sta_id == mvmvif->ap_sta_id)
-				mvm->d0i3_ap_sta_id = IWL_MVM_STATION_COUNT;
-			mvmvif->ap_sta_id = IWL_MVM_STATION_COUNT;
 			/* remove quota for this interface */
 			ret = iwl_mvm_update_quotas(mvm, NULL);
 			if (ret)