Address scenarios where repeated entry and exit from EMLSR occur, such as
encountering missed beacons on a specific link,
while still discovering that link during a scan.
To mitigate this, introduce the EMLSR prevention mechanism, which operates
as follows:
- On each exit from EMLSR event, record the timestamp and the exit
reason.
- If two consecutive exits happen for the same reason within a
400-second window, enforce a 300-second EMLSR prevention.
- If a third exit for the same reason occurs within 400 seconds from the
second exit, enforce an extended EMLSR prevention of 600 seconds.
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@xxxxxxxxx>
Reviewed-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
drivers/net/wireless/intel/iwlwifi/mvm/link.c | 52 +++++++++++++++++++
.../net/wireless/intel/iwlwifi/mvm/mac80211.c | 25 +++++++++
drivers/net/wireless/intel/iwlwifi/mvm/mvm.h | 23 ++++++++
3 files changed, 100 insertions(+)
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/link.c b/drivers/net/wireless/intel/iwlwifi/mvm/link.c
index acbe8e6f14c8..4bb71a14ac3b 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/link.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/link.c
@@ -712,6 +712,55 @@ u8 iwl_mvm_get_other_link(struct ieee80211_vif *vif, u8 link_id)
}
}
+/* Reasons that can cause esr prevention */
+#define IWL_MVM_ESR_PREVENT_REASONS IWL_MVM_ESR_EXIT_MISSED_BEACON
+#define IWL_MVM_PREVENT_ESR_TIMEOUT (HZ * 400)
+#define IWL_MVM_ESR_PREVENT_SHORT (HZ * 300)
+#define IWL_MVM_ESR_PREVENT_LONG (HZ * 600)
+
+static void iwl_mvm_recalc_esr_prevention(struct iwl_mvm *mvm,
+ struct iwl_mvm_vif *mvmvif,
+ enum iwl_mvm_esr_state reason)
+{
+ unsigned long now = jiffies;
+ unsigned long delay;
+ bool timeout_expired =
+ time_after(now, mvmvif->last_esr_exit.ts +
+ IWL_MVM_PREVENT_ESR_TIMEOUT);
+
+ if (WARN_ON(!(IWL_MVM_ESR_PREVENT_REASONS & reason)))
+ return;
+
+ lockdep_assert_held(&mvm->mutex);
+
+ mvmvif->last_esr_exit.ts = now;
+
+ if (timeout_expired ||
+ mvmvif->last_esr_exit.reason != reason) {
+ mvmvif->last_esr_exit.reason = reason;
+ mvmvif->exit_same_reason_count = 1;
+ return;
+ }
+
+ mvmvif->exit_same_reason_count++;
+ if (WARN_ON(mvmvif->exit_same_reason_count < 2 ||
+ mvmvif->exit_same_reason_count > 3))
+ return;
+
+ mvmvif->esr_disable_reason |= IWL_MVM_ESR_BLOCKED_PREVENTION;
+
+ delay = mvmvif->exit_same_reason_count == 2 ?
+ IWL_MVM_ESR_PREVENT_SHORT :
+ IWL_MVM_ESR_PREVENT_LONG;
+
+ IWL_DEBUG_INFO(mvm,
+ "Preventing EMLSR for %ld seconds due to %u exits with the reason 0x%x\n",
+ delay / HZ, mvmvif->exit_same_reason_count, reason);
+
+ wiphy_delayed_work_queue(mvm->hw->wiphy,
+ &mvmvif->prevent_esr_done_wk, delay);
+}
+
/* API to exit eSR mode */
void iwl_mvm_exit_esr(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
enum iwl_mvm_esr_state reason,
@@ -738,6 +787,9 @@ void iwl_mvm_exit_esr(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
reason, vif->active_links, new_active_links);
ieee80211_set_active_links_async(vif, new_active_links);
+
+ if (IWL_MVM_ESR_PREVENT_REASONS & reason)
+ iwl_mvm_recalc_esr_prevention(mvm, mvmvif, reason);
}
void iwl_mvm_block_esr(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
index efe9205a7cf2..ddf27e6d2df2 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
@@ -1612,6 +1612,19 @@ static int iwl_mvm_alloc_bcast_mcast_sta(struct iwl_mvm *mvm,
IWL_STA_MULTICAST);
}
+static void iwl_mvm_prevent_esr_done_wk(struct wiphy *wiphy,
+ struct wiphy_work *wk)
+{
+ struct iwl_mvm_vif *mvmvif =
+ container_of(wk, struct iwl_mvm_vif, prevent_esr_done_wk.work);
+ struct iwl_mvm *mvm = mvmvif->mvm;
+ struct ieee80211_vif *vif = iwl_mvm_get_bss_vif(mvm);
+
+ mutex_lock(&mvm->mutex);
+ iwl_mvm_unblock_esr(mvm, vif, IWL_MVM_ESR_BLOCKED_PREVENTION);
+ mutex_unlock(&mvm->mutex);
+}
+
void iwl_mvm_mac_init_mvmvif(struct iwl_mvm *mvm, struct iwl_mvm_vif *mvmvif)
{
lockdep_assert_held(&mvm->mutex);
@@ -1621,6 +1634,9 @@ void iwl_mvm_mac_init_mvmvif(struct iwl_mvm *mvm, struct iwl_mvm_vif *mvmvif)
INIT_DELAYED_WORK(&mvmvif->csa_work,
iwl_mvm_channel_switch_disconnect_wk);
+
+ wiphy_delayed_work_init(&mvmvif->prevent_esr_done_wk,
+ iwl_mvm_prevent_esr_done_wk);
}
static int iwl_mvm_mac_add_interface(struct ieee80211_hw *hw,
@@ -1764,6 +1780,9 @@ void iwl_mvm_prepare_mac_removal(struct iwl_mvm *mvm,
flush_work(&mvm->roc_done_wk);
}
+ wiphy_delayed_work_cancel(mvm->hw->wiphy,
+ &mvmvif->prevent_esr_done_wk);
+
cancel_delayed_work_sync(&mvmvif->csa_work);
}
@@ -3906,6 +3925,9 @@ iwl_mvm_sta_state_assoc_to_authorized(struct iwl_mvm *mvm,
callbacks->mac_ctxt_changed(mvm, vif, false);
iwl_mvm_mei_host_associated(mvm, vif, mvm_sta);
+ memset(&mvmvif->last_esr_exit, 0,
+ sizeof(mvmvif->last_esr_exit));
+
/* Calculate eSR mode due to BT coex */
iwl_mvm_bt_coex_update_vif_esr(mvm, vif);
@@ -3962,6 +3984,9 @@ iwl_mvm_sta_state_authorized_to_assoc(struct iwl_mvm *mvm,
/* disable beacon filtering */
iwl_mvm_disable_beacon_filter(mvm, vif);
+
+ wiphy_delayed_work_cancel(mvm->hw->wiphy,
+ &mvmvif->prevent_esr_done_wk);
}
return 0;
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
index 3f13b346bfc6..920fd0afbb59 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
@@ -354,15 +354,29 @@ struct iwl_mvm_vif_link_info {
* reasons - use iwl_mvm_exit_esr().
*
* @IWL_MVM_ESR_BLOCKED_COEX: COEX is preventing the enablement of EMLSR
+ * @IWL_MVM_ESR_BLOCKED_PREVENTION: Prevent EMLSR to avoid entering and exiting
+ * in a loop.
* @IWL_MVM_ESR_EXIT_MISSED_BEACON: exited EMLSR due to missed beacons
*/
enum iwl_mvm_esr_state {
IWL_MVM_ESR_BLOCKED_COEX = 0x1,
+ IWL_MVM_ESR_BLOCKED_PREVENTION = 0x2,
IWL_MVM_ESR_EXIT_MISSED_BEACON = 0x10000,
};
#define IWL_MVM_BLOCK_ESR_REASONS 0xffff
+/**
+ * struct iwl_mvm_esr_exit - details of the last exit from EMLSR mode.
+ * @reason: The reason for the last exit from EMLSR.
+ * &iwl_mvm_prevent_esr_reasons. Will be 0 before exiting EMLSR.
+ * @ts: the time stamp of the last time we existed EMLSR.
+ */
+struct iwl_mvm_esr_exit {
+ unsigned long ts;
+ enum iwl_mvm_esr_state reason;
+};
+
/**
* struct iwl_mvm_vif - data per Virtual Interface, it is a MAC context
* @mvm: pointer back to the mvm struct
@@ -404,6 +418,11 @@ enum iwl_mvm_esr_state {
* @link_selection_primary: primary link selected by link selection
* @primary_link: primary link in eSR. Valid only for an associated MLD vif,
* and in eSR mode. Valid only for a STA.
+ * @last_esr_exit: Details of the last exit from EMLSR.
+ * @exit_same_reason_count: The number of times we exited due to the specified
+ * @last_esr_exit::reason, only counting exits due to
+ * &IWL_MVM_ESR_PREVENT_REASONS.
+ * @prevent_esr_done_wk: work that should be done when esr prevention ends.
*/
struct iwl_mvm_vif {
struct iwl_mvm *mvm;
@@ -497,6 +516,10 @@ struct iwl_mvm_vif {
u16 link_selection_res;
u8 link_selection_primary;
u8 primary_link;
+ struct iwl_mvm_esr_exit last_esr_exit;
+ u8 exit_same_reason_count;
+ struct wiphy_delayed_work prevent_esr_done_wk;
+
struct iwl_mvm_vif_link_info deflink;
struct iwl_mvm_vif_link_info *link[IEEE80211_MLD_MAX_NUM_LINKS];
};
--
2.34.1
