wifi: iwlwifi: mvm: simplify the reorder buffer

The firmware / hardware of devices supporting RSS is able to report
duplicates and packets that time out inside the reoder buffer. We can
now remove all the complex logic that was implemented to keep all the Rx
queues more the less synchronized: we used to send a message to all the
queues through the firmware to teach the different queues about what is
the current SSN every 2048 packets.

Now that we rely on the firmware / hardware to detect duplicates, we can
completely remove the code that did that in the driver and it has been
reported that this code was spuriously dropping legit packets.
Suggested-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20231017115047.54cf4d3d5956.Ic06a08c9fb1e1ec315a4b49d632b78b8474dab79@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

@@ -647,18 +647,9 @@ struct iwl_mvm_tcm {
  * @queue: queue of this reorder buffer
  * @last_amsdu: track last ASMDU SN for duplication detection
  * @last_sub_index: track ASMDU sub frame index for duplication detection
- * @reorder_timer: timer for frames are in the reorder buffer. For AMSDU
- *	it is the time of last received sub-frame
- * @removed: prevent timer re-arming
  * @valid: reordering is valid for this queue
  * @lock: protect reorder buffer internal state
  * @mvm: mvm pointer, needed for frame timer context
- * @consec_oldsn_drops: consecutive drops due to old SN
- * @consec_oldsn_ampdu_gp2: A-MPDU GP2 timestamp to track
- *	when to apply old SN consecutive drop workaround
- * @consec_oldsn_prev_drop: track whether or not an MPDU
- *	that was single/part of the previous A-MPDU was
- *	dropped due to old SN
  */
 struct iwl_mvm_reorder_buffer {
 	u16 head_sn;
@@ -667,33 +658,21 @@ struct iwl_mvm_reorder_buffer {
 	int queue;
 	u16 last_amsdu;
 	u8 last_sub_index;
-	struct timer_list reorder_timer;
-	bool removed;
 	bool valid;
 	spinlock_t lock;
 	struct iwl_mvm *mvm;
-	unsigned int consec_oldsn_drops;
-	u32 consec_oldsn_ampdu_gp2;
-	unsigned int consec_oldsn_prev_drop:1;
 } ____cacheline_aligned_in_smp;
 
 /**
- * struct _iwl_mvm_reorder_buf_entry - reorder buffer entry per-queue/per-seqno
+ * struct iwl_mvm_reorder_buf_entry - reorder buffer entry per-queue/per-seqno
  * @frames: list of skbs stored
- * @reorder_time: time the packet was stored in the reorder buffer
  */
-struct _iwl_mvm_reorder_buf_entry {
-	struct sk_buff_head frames;
-	unsigned long reorder_time;
-};
-
-/* make this indirection to get the aligned thing */
 struct iwl_mvm_reorder_buf_entry {
-	struct _iwl_mvm_reorder_buf_entry e;
+	struct sk_buff_head frames;
 }
 #ifndef __CHECKER__
 /* sparse doesn't like this construct: "bad integer constant expression" */
-__aligned(roundup_pow_of_two(sizeof(struct _iwl_mvm_reorder_buf_entry)))
+__aligned(roundup_pow_of_two(sizeof(struct sk_buff_head)))
 #endif
 ;
 
@@ -2335,7 +2314,6 @@ void iwl_mvm_sync_rx_queues_internal(struct iwl_mvm *mvm,
 				     enum iwl_mvm_rxq_notif_type type,
 				     bool sync,
 				     const void *data, u32 size);
-void iwl_mvm_reorder_timer_expired(struct timer_list *t);
 struct ieee80211_vif *iwl_mvm_get_bss_vif(struct iwl_mvm *mvm);
 struct ieee80211_vif *iwl_mvm_get_vif_by_macid(struct iwl_mvm *mvm, u32 macid);
 bool iwl_mvm_is_vif_assoc(struct iwl_mvm *mvm);

drivers/net/wireless/intel/iwlwifi/mvm/sta.c

@@ -2719,18 +2719,9 @@ static void iwl_mvm_free_reorder(struct iwl_mvm *mvm,
 		WARN_ON(1);
 
 		for (j = 0; j < reorder_buf->buf_size; j++)
-			__skb_queue_purge(&entries[j].e.frames);
-		/*
-		 * Prevent timer re-arm. This prevents a very far fetched case
-		 * where we timed out on the notification. There may be prior
-		 * RX frames pending in the RX queue before the notification
-		 * that might get processed between now and the actual deletion
-		 * and we would re-arm the timer although we are deleting the
-		 * reorder buffer.
-		 */
-		reorder_buf->removed = true;
+			__skb_queue_purge(&entries[j].frames);
+
 		spin_unlock_bh(&reorder_buf->lock);
-		del_timer_sync(&reorder_buf->reorder_timer);
 	}
 }
 
@@ -2750,15 +2741,12 @@ static void iwl_mvm_init_reorder_buffer(struct iwl_mvm *mvm,
 		reorder_buf->num_stored = 0;
 		reorder_buf->head_sn = ssn;
 		reorder_buf->buf_size = buf_size;
-		/* rx reorder timer */
-		timer_setup(&reorder_buf->reorder_timer,
-			    iwl_mvm_reorder_timer_expired, 0);
 		spin_lock_init(&reorder_buf->lock);
 		reorder_buf->mvm = mvm;
 		reorder_buf->queue = i;
 		reorder_buf->valid = false;
 		for (j = 0; j < reorder_buf->buf_size; j++)
-			__skb_queue_head_init(&entries[j].e.frames);
+			__skb_queue_head_init(&entries[j].frames);
 	}
 }
 

drivers/net/wireless/intel/iwlwifi/mvm/sta.h

@@ -286,12 +286,10 @@ struct iwl_mvm_key_pn {
  *
  * @IWL_MVM_RXQ_EMPTY: empty sync notification
  * @IWL_MVM_RXQ_NOTIF_DEL_BA: notify RSS queues of delBA
- * @IWL_MVM_RXQ_NSSN_SYNC: notify all the RSS queues with the new NSSN
  */
 enum iwl_mvm_rxq_notif_type {
 	IWL_MVM_RXQ_EMPTY,
 	IWL_MVM_RXQ_NOTIF_DEL_BA,
-	IWL_MVM_RXQ_NSSN_SYNC,
 };
 
 /**
@@ -315,11 +313,6 @@ struct iwl_mvm_delba_data {
 	u32 baid;
 } __packed;
 
-struct iwl_mvm_nssn_sync_data {
-	u32 baid;
-	u32 nssn;
-} __packed;
-
 /**
  * struct iwl_mvm_rxq_dup_data - per station per rx queue data
  * @last_seq: last sequence per tid for duplicate packet detection