wifi: ath12k: fix mac id extraction when MSDU spillover in rx error path

Currently, in the rx error data path, mac id is extracted from the
last 64bits of MSDU end description tag for each entry received in
the WBM error ring. Then, each entry will be updated into the MSDU
list for further processing. The extracted mac id is valid when a
single MSDU is not fragmented and received in the WBM error ring.

In scenarios where the size of a single MSDU received exceeds the
descriptor buffer size, resulting in fragmented or spillover MSDU
entries into the WBM error ring. In this case, the extracted mac id
from each spillover entry is invalid except the last spillover entry
of the MSDU. This invalid mac id leads to packet rejection.

To address this issue, check if the MSDU continuation flag is set,
then extract the valid mac id from the last spillover entry.
Propagate the valid mac id to all the spillover entries of the single
MSDU in the temporary MSDU list(scatter_msdu_list). Then, update this
into the MSDU list (msdu_list) for further processing.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Signed-off-by: Nithyanantham Paramasivam <quic_nithp@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240404141538.1277258-1-quic_nithp@quicinc.com

drivers/net/wireless/ath/ath12k/dp_rx.c

@@ -239,6 +239,14 @@ static inline u8 ath12k_dp_rx_get_msdu_src_link(struct ath12k_base *ab,
 	return ab->hal_rx_ops->rx_desc_get_msdu_src_link_id(desc);
 }
 
+static void ath12k_dp_clean_up_skb_list(struct sk_buff_head *skb_list)
+{
+	struct sk_buff *skb;
+
+	while ((skb = __skb_dequeue(skb_list)))
+		dev_kfree_skb_any(skb);
+}
+
 static int ath12k_dp_purge_mon_ring(struct ath12k_base *ab)
 {
 	int i, reaped = 0;
@@ -3742,19 +3750,20 @@ int ath12k_dp_rx_process_wbm_err(struct ath12k_base *ab,
 	struct hal_rx_wbm_rel_info err_info;
 	struct hal_srng *srng;
 	struct sk_buff *msdu;
-	struct sk_buff_head msdu_list;
+	struct sk_buff_head msdu_list, scatter_msdu_list;
 	struct ath12k_skb_rxcb *rxcb;
 	void *rx_desc;
 	u8 mac_id;
 	int num_buffs_reaped = 0;
 	struct ath12k_rx_desc_info *desc_info;
 	int ret, pdev_id;
+	struct hal_rx_desc *msdu_data;
 
 	__skb_queue_head_init(&msdu_list);
+	__skb_queue_head_init(&scatter_msdu_list);
 
 	srng = &ab->hal.srng_list[dp->rx_rel_ring.ring_id];
 	rx_ring = &dp->rx_refill_buf_ring;
-
 	spin_lock_bh(&srng->lock);
 
 	ath12k_hal_srng_access_begin(ab, srng);
@@ -3807,17 +3816,53 @@ int ath12k_dp_rx_process_wbm_err(struct ath12k_base *ab,
 			continue;
 		}
 
+		msdu_data = (struct hal_rx_desc *)msdu->data;
 		rxcb->err_rel_src = err_info.err_rel_src;
 		rxcb->err_code = err_info.err_code;
-		rxcb->rx_desc = (struct hal_rx_desc *)msdu->data;
-
-		__skb_queue_tail(&msdu_list, msdu);
-
 		rxcb->is_first_msdu = err_info.first_msdu;
 		rxcb->is_last_msdu = err_info.last_msdu;
 		rxcb->is_continuation = err_info.continuation;
+		rxcb->rx_desc = msdu_data;
+
+		if (err_info.continuation) {
+			__skb_queue_tail(&scatter_msdu_list, msdu);
+			continue;
+		}
+
+		mac_id = ath12k_dp_rx_get_msdu_src_link(ab,
+							msdu_data);
+		if (mac_id >= MAX_RADIOS) {
+			dev_kfree_skb_any(msdu);
+
+			/* In any case continuation bit is set
+			 * in the previous record, cleanup scatter_msdu_list
+			 */
+			ath12k_dp_clean_up_skb_list(&scatter_msdu_list);
+			continue;
+		}
+
+		if (!skb_queue_empty(&scatter_msdu_list)) {
+			struct sk_buff *msdu;
+
+			skb_queue_walk(&scatter_msdu_list, msdu) {
+				rxcb = ATH12K_SKB_RXCB(msdu);
+				rxcb->mac_id = mac_id;
+			}
+
+			skb_queue_splice_tail_init(&scatter_msdu_list,
+						   &msdu_list);
+		}
+
+		rxcb = ATH12K_SKB_RXCB(msdu);
+		rxcb->mac_id = mac_id;
+		__skb_queue_tail(&msdu_list, msdu);
 	}
 
+	/* In any case continuation bit is set in the
+	 * last record, cleanup scatter_msdu_list
+	 */
+	ath12k_dp_clean_up_skb_list(&scatter_msdu_list);
+
 	ath12k_hal_srng_access_end(ab, srng);
 
 	spin_unlock_bh(&srng->lock);
@@ -3830,8 +3875,9 @@ int ath12k_dp_rx_process_wbm_err(struct ath12k_base *ab,
 
 	rcu_read_lock();
 	while ((msdu = __skb_dequeue(&msdu_list))) {
-		mac_id = ath12k_dp_rx_get_msdu_src_link(ab,
-							(struct hal_rx_desc *)msdu->data);
+		rxcb = ATH12K_SKB_RXCB(msdu);
+		mac_id = rxcb->mac_id;
+
 		pdev_id = ath12k_hw_mac_id_to_pdev_id(ab->hw_params, mac_id);
 		ar = ab->pdevs[pdev_id].ar;