qcacld-3.0: Fix HDD IPA stability issues

SKBs received through IPA exception path are not allocate by WLAN
driver and we should not pass these SKBs to driver SKB debug hash
infrastructure(for free clean up). So use kfree_skb instead of
qdf_nbuf_free for IPA exception data path.
Add ssr protection and wlan_hdd_validate_context in hdd_ipa_w2i_cb.

Change-Id: I593efad97cbe2629bf0b96cbde587d092b81babb
CRs-Fixed: 1076635

core/hdd/src/wlan_hdd_ipa.c

@@ -952,7 +952,7 @@ void hdd_ipa_uc_stat_query(hdd_context_t *pHddCtx,
 		(false == hdd_ipa->resource_loading)) {
 		*ipa_tx_diff = hdd_ipa->ipa_tx_packets_diff;
 		*ipa_rx_diff = hdd_ipa->ipa_rx_packets_diff;
-		HDD_IPA_LOG(LOG1, "STAT Query TX DIFF %d, RX DIFF %d",
+		HDD_IPA_LOG(LOGOFF, "STAT Query TX DIFF %d, RX DIFF %d",
 			    *ipa_tx_diff, *ipa_rx_diff);
 	}
 	qdf_mutex_release(&hdd_ipa->ipa_lock);
@@ -2482,13 +2482,13 @@ static void hdd_ipa_send_skb_to_network(qdf_nbuf_t skb,
 		HDD_IPA_LOG(QDF_TRACE_LEVEL_INFO_LOW, "Invalid adapter: 0x%p",
 			    adapter);
 		HDD_IPA_INCREASE_INTERNAL_DROP_COUNT(hdd_ipa);
-		qdf_nbuf_free(skb);
+		kfree_skb(skb);
 		return;
 	}
 
 	if (cds_is_driver_unloading()) {
 		HDD_IPA_INCREASE_INTERNAL_DROP_COUNT(hdd_ipa);
-		qdf_nbuf_free(skb);
+		kfree_skb(skb);
 		return;
 	}
 
@@ -2510,7 +2510,7 @@ static void hdd_ipa_send_skb_to_network(qdf_nbuf_t skb,
 }
 
 /**
- * hdd_ipa_w2i_cb() - WLAN to IPA callback handler
+ * __hdd_ipa_w2i_cb() - WLAN to IPA callback handler
  * @priv: pointer to private data registered with IPA (we register a
  *	pointer to the global IPA context)
  * @evt: the IPA event which triggered the callback
@@ -2518,7 +2518,7 @@ static void hdd_ipa_send_skb_to_network(qdf_nbuf_t skb,
  *
  * Return: None
  */
-static void hdd_ipa_w2i_cb(void *priv, enum ipa_dp_evt_type evt,
+static void __hdd_ipa_w2i_cb(void *priv, enum ipa_dp_evt_type evt,
 			   unsigned long data)
 {
 	struct hdd_ipa_priv *hdd_ipa = NULL;
@@ -2530,12 +2530,27 @@ static void hdd_ipa_w2i_cb(void *priv, enum ipa_dp_evt_type evt,
 	qdf_nbuf_t copy;
 	uint8_t fw_desc;
 	int ret;
+	QDF_STATUS status = QDF_STATUS_SUCCESS;
 
 	hdd_ipa = (struct hdd_ipa_priv *)priv;
 
 	switch (evt) {
 	case IPA_RECEIVE:
 		skb = (qdf_nbuf_t) data;
+
+		/*
+		 * When SSR is going on or driver is unloading,
+		 * just drop the packets.
+		 */
+		status = wlan_hdd_validate_context(hdd_ipa->hdd_ctx);
+		if (0 != status) {
+			HDD_IPA_LOG(QDF_TRACE_LEVEL_ERROR,
+					"Invalid context: drop packet");
+			HDD_IPA_INCREASE_INTERNAL_DROP_COUNT(hdd_ipa);
+			kfree_skb(skb);
+			return;
+		}
+
 		if (hdd_ipa_uc_is_enabled(hdd_ipa->hdd_ctx)) {
 			session_id = (uint8_t)skb->cb[0];
 			iface_id = vdev_to_iface[session_id];
@@ -2553,7 +2568,7 @@ static void hdd_ipa_w2i_cb(void *priv, enum ipa_dp_evt_type evt,
 			HDD_IPA_DBG_DUMP(QDF_TRACE_LEVEL_INFO_HIGH,
 				"w2i -- skb", skb->data, 8);
 			HDD_IPA_INCREASE_INTERNAL_DROP_COUNT(hdd_ipa);
-			qdf_nbuf_free(skb);
+			kfree_skb(skb);
 			return;
 		}
 
@@ -2613,7 +2628,7 @@ static void hdd_ipa_w2i_cb(void *priv, enum ipa_dp_evt_type evt,
 			if (fw_desc & HDD_IPA_FW_RX_DESC_DISCARD_M) {
 				HDD_IPA_INCREASE_INTERNAL_DROP_COUNT(hdd_ipa);
 				hdd_ipa->ipa_rx_discard++;
-				qdf_nbuf_free(skb);
+				kfree_skb(skb);
 				break;
 			}
 
@@ -2632,6 +2647,23 @@ static void hdd_ipa_w2i_cb(void *priv, enum ipa_dp_evt_type evt,
 	}
 }
 
+/**
+ * hdd_ipa_w2i_cb() - SSR wrapper for __hdd_ipa_w2i_cb
+ * @priv: pointer to private data registered with IPA (we register a
+ *	pointer to the global IPA context)
+ * @evt: the IPA event which triggered the callback
+ * @data: data associated with the event
+ *
+ * Return: None
+ */
+static void hdd_ipa_w2i_cb(void *priv, enum ipa_dp_evt_type evt,
+			   unsigned long data)
+{
+	cds_ssr_protect(__func__);
+	__hdd_ipa_w2i_cb(priv, evt, data);
+	cds_ssr_unprotect(__func__);
+}
+
 /**
  * hdd_ipa_nbuf_cb() - IPA TX complete callback
  * @skb: packet buffer which was transmitted