From ee32bdc3360cb5a73f9e491252bc0f0931a911c6 Mon Sep 17 00:00:00 2001
From: Chen Wen <chenwen@espressif.com>
Date: Fri, 9 Nov 2018 17:42:53 +0800
Subject: [PATCH] feat(lwip): Add to prevent switch to tcpip thread between
 mbox post and sem wait

---
 components/lwip/lwip/src/api/tcpip.c           |  9 +++++++++
 .../lwip/port/esp8266/freertos/sys_arch.c      | 10 ++++++++++
 .../lwip/port/esp8266/include/arch/sys_arch.h  | 18 ++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/components/lwip/lwip/src/api/tcpip.c b/components/lwip/lwip/src/api/tcpip.c
index 1f3fb61c..e229f333 100644
--- a/components/lwip/lwip/src/api/tcpip.c
+++ b/components/lwip/lwip/src/api/tcpip.c
@@ -344,8 +344,17 @@ tcpip_send_msg_wait_sem(tcpip_callback_fn fn, void *apimsg, sys_sem_t* sem)
   TCPIP_MSG_VAR_REF(msg).type = TCPIP_MSG_API;
   TCPIP_MSG_VAR_REF(msg).msg.api_msg.function = fn;
   TCPIP_MSG_VAR_REF(msg).msg.api_msg.msg = apimsg;
+#if ESP_LWIP
+  u8_t prio = sys_thread_priority_get(NULL); 	  // add to prevent switch to tcpip thread between mbox post and sem wait
+  if((TCPIP_THREAD_PRIO + 1) > prio) {
+    sys_thread_priority_set(NULL, TCPIP_THREAD_PRIO + 1);  // set priority higher than tcpip thread
+  }
+#endif
   sys_mbox_post(&mbox, &TCPIP_MSG_VAR_REF(msg));
   sys_arch_sem_wait(sem, 0);
+#if ESP_LWIP
+  sys_thread_priority_set(NULL, prio);  
+#endif
   TCPIP_MSG_VAR_FREE(msg);
   return ERR_OK;
 #endif /* LWIP_TCPIP_CORE_LOCKING */
diff --git a/components/lwip/port/esp8266/freertos/sys_arch.c b/components/lwip/port/esp8266/freertos/sys_arch.c
index e3bc1b4c..c4718b79 100644
--- a/components/lwip/port/esp8266/freertos/sys_arch.c
+++ b/components/lwip/port/esp8266/freertos/sys_arch.c
@@ -438,6 +438,16 @@ sys_arch_msleep(int ms)
 	vTaskDelay(ms / portTICK_RATE_MS);
 }
 
+u8_t sys_thread_priority_get(sys_thread_t thread_handle)
+{
+    return (u8_t)uxTaskPriorityGet(thread_handle);
+}
+
+void sys_thread_priority_set(sys_thread_t thread_handle, u8_t priority)
+{
+    vTaskPrioritySet(thread_handle, (UBaseType_t)priority);
+}
+
 #if LWIP_NETCONN_SEM_PER_THREAD
 
 static void sys_thread_sem_free(int index, void *data) // destructor for TLS semaphore
diff --git a/components/lwip/port/esp8266/include/arch/sys_arch.h b/components/lwip/port/esp8266/include/arch/sys_arch.h
index 4b3bd8a8..a1a5c3bf 100644
--- a/components/lwip/port/esp8266/include/arch/sys_arch.h
+++ b/components/lwip/port/esp8266/include/arch/sys_arch.h
@@ -48,6 +48,24 @@ typedef xTaskHandle sys_thread_t;
 #define sys_sem_valid( x ) ( ( ( *x ) == NULL) ? pdFALSE : pdTRUE )
 #define sys_sem_set_invalid( x ) ( ( *x ) = NULL )
 
+/**
+ * Get thread priority througth thread_handle
+ *
+ * @param task_handle
+ *
+ * @return thread priority
+ */
+u8_t sys_thread_priority_get(sys_thread_t thread_handle);
+
+/**
+ * Set thread priority througth thread_handle
+ *
+ * @param task_handle
+ *
+ * @param priority
+ */
+void sys_thread_priority_set(sys_thread_t thread_handle, u8_t priority);
+
 #define LWIP_COMPAT_MUTEX 0
 
 #if LWIP_NETCONN_SEM_PER_THREAD