[PATCH 3/3] wifi: iwlwifi: mld: skip TX when firmware is dead

[Cole Leavitt <cole@unwrap.rs>]

When firmware encounters an error, STATUS_FW_ERROR is set but the
mac80211 TX path continues pulling frames from TXQs. Each frame
fails at iwl_trans_tx() which checks STATUS_FW_ERROR and returns
-EIO, but iwl_mld_tx_from_txq() keeps looping over every queued
frame. This burns CPU in a tight loop on dead firmware and can
cause soft lockups during firmware error recovery.

Add a STATUS_FW_ERROR check at the top of iwl_mld_tx_from_txq()
to stop pulling frames from mac80211 TXQs when firmware is dead.
Also guard iwl_mld_mac80211_tx() which bypasses the TXQ path
entirely and would otherwise continue feeding frames to dead
firmware.

Once STATUS_FW_ERROR is cleared during firmware restart, TX
resumes naturally with no explicit wake needed.

Fixes: d1e879ec600f ("wifi: iwlwifi: add iwlmld sub-driver")
Signed-off-by: Cole Leavitt <cole@unwrap.rs>
---
 drivers/net/wireless/intel/iwlwifi/mld/mac80211.c | 4 ++++
 drivers/net/wireless/intel/iwlwifi/mld/tx.c       | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/mld/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mld/mac80211.c
index 71a9a72c9ac0..0df3be3089c3 100644
--- a/drivers/net/wireless/intel/iwlwifi/mld/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mld/mac80211.c
@@ -519,6 +519,10 @@ iwl_mld_mac80211_tx(struct ieee80211_hw *hw,
 	u32 link_id = u32_get_bits(info->control.flags,
 				   IEEE80211_TX_CTRL_MLO_LINK);
 
+	if (unlikely(test_bit(STATUS_FW_ERROR, &mld->trans->status))) {
+		ieee80211_free_txskb(hw, skb);
+		return;
+	}
 	/* In AP mode, mgmt frames are sent on the bcast station,
 	 * so the FW can't translate the MLD addr to the link addr. Do it here
 	 */
diff --git a/drivers/net/wireless/intel/iwlwifi/mld/tx.c b/drivers/net/wireless/intel/iwlwifi/mld/tx.c
index 8af58aabcd68..33bd2e336166 100644
--- a/drivers/net/wireless/intel/iwlwifi/mld/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/mld/tx.c
@@ -962,6 +962,9 @@ void iwl_mld_tx_from_txq(struct iwl_mld *mld, struct ieee80211_txq *txq)
 	struct sk_buff *skb = NULL;
 	u8 zero_addr[ETH_ALEN] = {};
 
+	if (unlikely(test_bit(STATUS_FW_ERROR, &mld->trans->status)))
+		return;
+
 	/*
 	 * No need for threads to be pending here, they can leave the first
 	 * taker all the work.
-- 
2.52.0