recvfrom(): Correct wait for new data when NET_UDP_READAHEAD is enabled. Fix size accounting when recvfrom_udpreadahead() sets state.rf_recvlen == -1. I have not checked if data are accumulated to the right position in the buffer however.

Signed-off-by: Pavel Pisa <ppisa@pikron.com>

ChangeLog

@@ -10842,3 +10842,15 @@
 	* arch/arm/src/lpc17/lpc17_irq.c: Set NVIC vector address so that
 	  code can execute with a bootloader or can execute from RAM.  From
 	  Pavel Pisa (2015-08-20).
+	* All ARMV7-M IRQ setup:  Always set the NVIC vector table address
+	  unconditionally.  This is needed in cases where the code is running
+	  with a bootload and when the code is running from RAM.  It is also
+	  needed by the logic of up_ramvec_initialize() which gets the vector
+	  base address from the NVIC.  Suggested by Pavel Pisa (2015-08-21).
+	* SAMV7 USBHS DCD: The device controller driver is (finally) functional
+	  (2015-08-21).
+	* recvfrom(): Correct wait for new data when NET_UDP_READAHEAD is
+	  enabled.  Fix size accounting when recvfrom_udpreadahead() sets
+	  state.rf_recvlen == -1.  I have not checked if data are accumulated
+	  to the right position in the buffer however. From Pavel Pisa
+	  (2015-08-15).

arch

@@ -1 +1 @@
-Subproject commit 76efd5e60a14c9e3b312b6f11c7c67de972a8299
+Subproject commit 94705f285e98a1ec5ca66027be01eff2e1189e27

net/socket/recvfrom.c

@@ -110,6 +110,39 @@ struct recvfrom_s
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Function: recvfrom_add_recvlen
+ *
+ * Description:
+ *   Update information about space available for new data and update size
+ *   of data in buffer,  This logic accounts for the case where
+ *   recvfrom_udpreadahead() sets state.rf_recvlen == -1 .
+ *
+ * Parameters:
+ *   pstate   recvfrom state structure
+ *   recvlen  size of new data appended to buffer
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_NET_UDP) || defined(CONFIG_NET_TCP) || defined(CONFIG_NET_PKT)
+
+static inline void recvfrom_add_recvlen(FAR struct recvfrom_s *pstate,
+                                        size_t recvlen)
+{
+  if (pstate->rf_recvlen < 0)
+    {
+      pstate->rf_recvlen = 0;
+    }
+
+  pstate->rf_recvlen += recvlen;
+  pstate->rf_buffer  += recvlen;
+  pstate->rf_buflen  -= recvlen;
+}
+#endif /* CONFIG_NET_UDP || CONFIG_NET_TCP || CONFIG_NET_PKT */
+
 /****************************************************************************
  * Function: recvfrom_newdata
  *
@@ -152,9 +185,7 @@ static size_t recvfrom_newdata(FAR struct net_driver_s *dev,
 
   /* Update the accumulated size of the data read */
 
-  pstate->rf_recvlen += recvlen;
+  recvfrom_add_recvlen(pstate, recvlen);
-  pstate->rf_buffer  += recvlen;
-  pstate->rf_buflen  -= recvlen;
 
   return recvlen;
 }
@@ -200,9 +231,7 @@ static void recvfrom_newpktdata(FAR struct net_driver_s *dev,
 
   /* Update the accumulated size of the data read */
 
-  pstate->rf_recvlen += recvlen;
+  recvfrom_add_recvlen(pstate, recvlen);
-  pstate->rf_buffer  += recvlen;
-  pstate->rf_buffer  -= recvlen;
 }
 #endif /* CONFIG_NET_PKT */
 
@@ -353,9 +382,7 @@ static inline void recvfrom_tcpreadahead(struct recvfrom_s *pstate)
 
       /* Update the accumulated size of the data read */
 
-      pstate->rf_recvlen += recvlen;
+      recvfrom_add_recvlen(pstate, recvlen);
-      pstate->rf_buffer  += recvlen;
-      pstate->rf_buflen  -= recvlen;
 
       /* If we took all of the ata from the I/O buffer chain is empty, then
        * release it.  If there is still data available in the I/O buffer
@@ -1501,9 +1528,11 @@ static ssize_t udp_recvfrom(FAR struct socket *psock, FAR void *buf, size_t len,
   /* It is okay to block if we need to.  If there is space to receive anything
    * more, then we will wait to receive the data.  Otherwise return the number
    * of bytes read from the read-ahead buffer (already in 'ret').
+   *
+   * NOTE: that recvfrom_udpreadahead() may set state.rf_recvlen == -1.
    */
 
-  else if (state.rf_recvlen == 0)
+  else if (state.rf_recvlen <= 0)
 #endif
     {
       /* Get the device that will handle the packet transfers.  This may be