mq_timedsend(): Do check for time errors if the message queue is not full. Noted by Freddie Chopin

TODO

@@ -12,7 +12,7 @@ nuttx/
   (1)  Memory Managment (mm/)
   (3)  Signals (sched/signal, arch/)
   (2)  pthreads (sched/pthread)
-  (1)  Message Queues (sched/mqueue)
+  (0)  Message Queues (sched/mqueue)
   (4)  C++ Support
   (6)  Binary loaders (binfmt/)
  (12)  Network (net/, drivers/net)
@@ -393,25 +393,9 @@ o pthreads (sched/pthreads)
                solution. So I discarded a few hours of programming. Not a
                big loss from the experience I gained."
 
-Message Queues (sched/mqueue)
+o Message Queues (sched/mqueue)
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-  Title:       mq_timedsend() ERROR DETECTION
-  Description: mq_timedsend() will always return an error an invalid time is
-               provided.  However, OpenGroup.org says:
-
-               "Under no circumstance shall the operation fail with a timeout
-                if there is sufficient room in the queue to add the message
-                immediately. The validity of the abstime parameter need not be
-                checked when there is sufficient room in the queue."
-
-  Status:       Open
-  Priority:     Low.  This is a valid POSIX compliance issue, but not thought
-                to be really important in real work programming.  It could
-                be used to conditionally block like O_NONBLOCK by providing a
-                bad time to the function.  That seeks hokey and I can't think
-                of any other real world use case the demands this functionality.
-
 o Kernel/Protected Build
   ^^^^^^^^^^^^^^^^^^^^^^
 

configs/samv71-xult/README.txt

@@ -233,7 +233,11 @@ Configurations
     Configures the NuttShell (nsh) located at examples/nsh.
     NOTES:
 
-    1. Default stack sizes are large and should really be tuned to reduce
+    1. The serial console is configured by default for use with and Arduino
+       serial shield (UART3).  You will need to reconfigure if you will
+       to use a different U[S]ART.
+
+    2. Default stack sizes are large and should really be tuned to reduce
        the RAM footprint:
 
          CONFIG_ARCH_INTERRUPTSTACK=2048
@@ -242,10 +246,18 @@ Configurations
          CONFIG_PTHREAD_STACK_DEFAULT=2048
          ... and others ...
 
-    2. NSH built-in applications are supported.
+    3. NSH built-in applications are supported.
 
        Binary Formats:
          CONFIG_BUILTIN=y                    : Enable support for built-in programs
 
        Application Configuration:
          CONFIG_NSH_BUILTIN_APPS=y           : Enable starting apps from NSH command line
+
+    4. Performance-related Configuration settings:
+
+       # CONFIG_ARMV7M_ICACHE is not set     : Can be enabled, not verified
+       # CONFIG_ARMV7M_DCACHE is not set     : Can be enabled, not verified
+       # CONFIG_ARCH_FPU is not set          : Can be enabled, not verified
+       # CONFIG_ARMV7M_ITCM is not set       : Support not yet in place
+       # CONFIG_ARMV7M_DTCM is not set       : Support not yet in place

configs/samv71-xult/nsh/defconfig

@@ -212,10 +212,10 @@ CONFIG_SAMV7_HAVE_USART2=y
 # CONFIG_SAMV7_TWIM0 is not set
 # CONFIG_SAMV7_TWIM1 is not set
 # CONFIG_SAMV7_TWIM2 is not set
-CONFIG_SAMV7_UART0=y
+# CONFIG_SAMV7_UART0 is not set
 # CONFIG_SAMV7_UART1 is not set
 # CONFIG_SAMV7_UART2 is not set
-# CONFIG_SAMV7_UART3 is not set
+CONFIG_SAMV7_UART3=y
 # CONFIG_SAMV7_UART4 is not set
 # CONFIG_SAMV7_USBDEVHS is not set
 # CONFIG_SAMV7_USBHOSTHS is not set
@@ -480,10 +480,10 @@ CONFIG_SERIAL=y
 # CONFIG_DEV_LOWCONSOLE is not set
 # CONFIG_16550_UART is not set
 # CONFIG_ARCH_HAVE_UART is not set
-CONFIG_ARCH_HAVE_UART0=y
+# CONFIG_ARCH_HAVE_UART0 is not set
 # CONFIG_ARCH_HAVE_UART1 is not set
 # CONFIG_ARCH_HAVE_UART2 is not set
-# CONFIG_ARCH_HAVE_UART3 is not set
+CONFIG_ARCH_HAVE_UART3=y
 # CONFIG_ARCH_HAVE_UART4 is not set
 # CONFIG_ARCH_HAVE_UART5 is not set
 # CONFIG_ARCH_HAVE_UART6 is not set
@@ -511,21 +511,22 @@ CONFIG_STANDARD_SERIAL=y
 # CONFIG_SERIAL_OFLOWCONTROL is not set
 CONFIG_ARCH_HAVE_SERIAL_TERMIOS=y
 # CONFIG_SERIAL_TERMIOS is not set
-CONFIG_UART0_SERIAL_CONSOLE=y
+# CONFIG_UART0_SERIAL_CONSOLE is not set
+CONFIG_UART3_SERIAL_CONSOLE=y
 # CONFIG_OTHER_SERIAL_CONSOLE is not set
 # CONFIG_NO_SERIAL_CONSOLE is not set
 
 #
-# UART0 Configuration
+# UART3 Configuration
 #
-CONFIG_UART0_RXBUFSIZE=256
+CONFIG_UART3_RXBUFSIZE=256
-CONFIG_UART0_TXBUFSIZE=256
+CONFIG_UART3_TXBUFSIZE=256
-CONFIG_UART0_BAUD=115200
+CONFIG_UART3_BAUD=115200
-CONFIG_UART0_BITS=8
+CONFIG_UART3_BITS=8
-CONFIG_UART0_PARITY=0
+CONFIG_UART3_PARITY=0
-CONFIG_UART0_2STOP=0
+CONFIG_UART3_2STOP=0
-# CONFIG_UART0_IFLOWCONTROL is not set
+# CONFIG_UART3_IFLOWCONTROL is not set
-# CONFIG_UART0_OFLOWCONTROL is not set
+# CONFIG_UART3_OFLOWCONTROL is not set
 # CONFIG_USBDEV is not set
 # CONFIG_USBHOST is not set
 # CONFIG_WIRELESS is not set

sched/mqueue/mq_send.c

@@ -180,4 +180,3 @@ int mq_send(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio)
   sched_unlock();
   return ret;
 }
-

sched/mqueue/mq_sndinternal.c

@@ -306,7 +306,7 @@ int mq_waitsend(mqd_t mqdes)
  *
  * Description:
  *   This is internal, common logic shared by both mq_send and mq_timesend.
- *   This function adds the specificied message (msg) to the message queue
+ *   This function adds the specified message (msg) to the message queue
  *   (mqdes).  Then it notifies any tasks that were waiting for message
  *   queue notifications setup by mq_notify.  And, finally, it awakens any
  *   tasks that were waiting for the message not empty event.

sched/mqueue/mq_timedsend.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  *  sched/mqueue/mq_timedsend.c
  *
- *   Copyright (C) 2007-2009, 2011, 2013-2014 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011, 2013-2015 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -187,6 +187,8 @@ int mq_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio,
   FAR struct mqueue_inode_s *msgq;
   FAR struct mqueue_msg_s *mqmsg = NULL;
   irqstate_t saved_state;
+  int ticks;
+  int result;
   int ret = ERROR;
 
   DEBUGASSERT(up_interrupt_context() == false && rtcb->waitdog == NULL);
@@ -200,16 +202,42 @@ int mq_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio,
       return ERROR;
     }
 
-  if (!abstime || abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
-    {
-      set_errno(EINVAL);
-      return ERROR;
-    }
-
   /* Get a pointer to the message queue */
 
   msgq = mqdes->msgq;
 
+  /* OpenGroup.org: "Under no circumstance shall the operation fail with a
+   * timeout if there is sufficient room in the queue to add the message
+   * immediately. The validity of the abstime parameter need not be checked
+   * when there is sufficient room in the queue."
+   *
+   * Also ignore the time value if for some crazy reason we were called from
+   * an interrupt handler.  This probably really should be an assertion.
+   */
+
+  sched_lock();
+  if (msgq->nmsgs < msgq->maxmsgs || up_interrupt_context())
+    {
+      /* The message queue is not full... Ignore the time parameter and
+       * let mq_send do the work.
+       */
+
+      ret = mq_send(mqdes, msg, msglen, prio);
+      sched_unlock();
+      return ret;
+    }
+
+  /* The message queue is full... We are going to wait.  Now we must have a
+   * valid time value.
+   */
+
+  if (!abstime || abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+    {
+      set_errno(EINVAL);
+      sched_unlock();
+      return ERROR;
+    }
+
   /* Create a watchdog.  We will not actually need this watchdog
    * unless the queue is full, but we will reserve it up front
    * before we enter the following critical section.
@@ -219,36 +247,19 @@ int mq_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio,
   if (!rtcb->waitdog)
     {
       set_errno(EINVAL);
+      sched_unlock();
       return ERROR;
     }
 
-  /* Allocate a message structure:
+  /* We are not in an interrupt handler and the message queue is full.
-   * - If we are called from an interrupt handler, or
+   * Set up a timed wait for the message queue to become non-full.
-   * - If the message queue is not full, or
-   */
-
-  sched_lock();
-  saved_state = irqsave();
-  if (up_interrupt_context()      || /* In an interrupt handler */
-      msgq->nmsgs < msgq->maxmsgs)   /* OR Message queue not full */
-    {
-      /* Allocate the message */
-
-      irqrestore(saved_state);
-      mqmsg = mq_msgalloc();
-    }
-  else
-    {
-      int ticks;
-
-      /* We are not in an interupt handler and the message queue is full.
-       * set up a timed wait for the message queue to become non-full.
    *
    * Convert the timespec to clock ticks.  We must have interrupts
    * disabled here so that this time stays valid until the wait begins.
    */
 
-      int result = clock_abstime2ticks(CLOCK_REALTIME, abstime, &ticks);
+  saved_state = irqsave();
+  result = clock_abstime2ticks(CLOCK_REALTIME, abstime, &ticks);
 
   /* If the time has already expired and the message queue is empty,
    * return immediately.
@@ -269,7 +280,7 @@ int mq_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio,
 
   /* Start the watchdog and begin the wait for MQ not full */
 
-      if (result == OK)
+  else
     {
       /* Start the watchdog */
 
@@ -298,20 +309,20 @@ int mq_timedsend(mqd_t mqdes, FAR const char *msg, size_t msglen, int prio,
   if (ret == OK)
     {
       mqmsg = mq_msgalloc();
-        }
+      if (!mqmsg)
-    }
-
-  /* Check if we were able to get a message structure -- this can fail
-   * either because we cannot send the message (and didn't bother trying
-   * to allocate it) or because the allocation failed.
-   */
-
-  if (mqmsg)
         {
-      /* Yes, peform the message send. */
+          /* Failed to allocate the message */
+
+          set_errno(ENOMEM);
+          ret = ERROR;
+        }
+      else
+        {
+          /* Perform the message send. */
 
           ret = mq_dosend(mqdes, mqmsg, msg, msglen, prio);
         }
+    }
 
   sched_unlock();
   wd_delete(rtcb->waitdog);