qcacmn: Protect rx execution context for wmi events

wmi rx event context can be modified at runtime by
upper layers. Protect rx execution context for wmi events
to avoid race conditions.

Change-Id: I7eed7108d09f8f39432990b2ebfef29a41bfa9aa
CRs-Fixed: 983619

wmi_unified.c

@@ -967,7 +967,9 @@ int wmi_unified_register_event_handler(wmi_unified_t wmi_handle,
 	idx = wmi_handle->max_event_idx;
 	wmi_handle->event_handler[idx] = handler_func;
 	wmi_handle->event_id[idx] = event_id;
+	qdf_spin_lock_bh(&wmi_handle->ctx_lock);
 	wmi_handle->ctx[idx] = rx_ctx;
+	qdf_spin_unlock_bh(&wmi_handle->ctx_lock);
 	wmi_handle->max_event_idx++;
 
 	return 0;
@@ -1082,7 +1084,9 @@ void wmi_control_rx(void *ctx, HTC_PACKET *htc_packet)
 		qdf_nbuf_free(evt_buf);
 		return;
 	}
+	qdf_spin_lock_bh(&wmi_handle->ctx_lock);
 	exec_ctx = wmi_handle->ctx[idx];
+	qdf_spin_unlock_bh(&wmi_handle->ctx_lock);
 
 	if (exec_ctx == WMI_RX_WORK_CTX) {
 		wmi_process_fw_event_worker_thread_ctx
@@ -1282,6 +1286,7 @@ void *wmi_unified_attach(void *scn_handle,
 	/* Assign target cookie capablity */
 	wmi_handle->use_cookie = use_cookie;
 	wmi_handle->osdev = osdev;
+	qdf_spinlock_create(&wmi_handle->ctx_lock);
 
 	return wmi_handle;
 }
@@ -1305,6 +1310,7 @@ void wmi_unified_detach(struct wmi_unified *wmi_handle)
 		buf = qdf_nbuf_queue_remove(&wmi_handle->event_queue);
 	}
 	qdf_spin_unlock_bh(&wmi_handle->eventq_lock);
+	qdf_spinlock_destroy(&wmi_handle->ctx_lock);
 	if (wmi_handle != NULL) {
 		OS_FREE(wmi_handle);
 		wmi_handle = NULL;