wqueue: optimize work_s structure

Change-Id: I908ac2fcead3a6fed3078b2339392ed93d2e4809
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>

include/nuttx/wqueue.h

@@ -245,14 +245,17 @@ typedef CODE void (*worker_t)(FAR void *arg);
 
 struct work_s
 {
-  struct sq_entry_s sq;  /* Implements a single linked list */
   union
   {
-    struct wdog_s timer; /* Delay expiry timer */
-    clock_t qtime;       /* Time work queued */
+    struct
+    {
+      struct sq_entry_s sq; /* Implements a single linked list */
+      clock_t qtime;        /* Time work queued */
+    } s;
+    struct wdog_s timer;    /* Delay expiry timer */
   } u;
-  worker_t  worker;      /* Work callback */
-  FAR void *arg;         /* Callback argument */
+  worker_t  worker;         /* Work callback */
+  FAR void *arg;            /* Callback argument */
 };
 
 /* This is an enumeration of the various events that may be

libs/libc/wqueue/work_cancel.c

@@ -87,7 +87,7 @@ static int work_qcancel(FAR struct usr_wqueue_s *wqueue,
        */
 
       curr = wqueue->q.head;
-      while (curr && curr != &work->sq)
+      while (curr && curr != &work->u.s.sq)
         {
           prev = curr;
           curr = curr->flink;

libs/libc/wqueue/work_queue.c

@@ -86,9 +86,9 @@ static int work_qqueue(FAR struct usr_wqueue_s *wqueue,
 
   /* Initialize the work structure */
 
-  work->worker = worker;           /* Work callback. non-NULL means queued */
-  work->arg    = arg;              /* Callback argument */
-  work->u.qtime = clock() + delay; /* Delay until work performed */
+  work->worker = worker;             /* Work callback. non-NULL means queued */
+  work->arg    = arg;                /* Callback argument */
+  work->u.s.qtime = clock() + delay; /* Delay until work performed */
 
   /* Do the easy case first -- when the work queue is empty. */
 
@@ -96,7 +96,7 @@ static int work_qqueue(FAR struct usr_wqueue_s *wqueue,
     {
       /* Add the watchdog to the head == tail of the queue. */
 
-      sq_addfirst(&work->sq, &wqueue->q);
+      sq_addfirst(&work->u.s.sq, &wqueue->q);
       _SEM_POST(&wqueue->wake);
     }
 
@@ -110,7 +110,7 @@ static int work_qqueue(FAR struct usr_wqueue_s *wqueue,
 
       do
         {
-          delta = work->u.qtime - ((FAR struct work_s *)curr)->u.qtime;
+          delta = work->u.s.qtime - ((FAR struct work_s *)curr)->u.s.qtime;
           if (delta < 0)
             {
               break;
@@ -127,7 +127,7 @@ static int work_qqueue(FAR struct usr_wqueue_s *wqueue,
         {
           /* Insert the watchdog at the head of the list */
 
-          sq_addfirst(&work->sq, &wqueue->q);
+          sq_addfirst(&work->u.s.sq, &wqueue->q);
           _SEM_GETVALUE(&wqueue->wake, &semcount);
           if (semcount < 1)
             {
@@ -138,7 +138,7 @@ static int work_qqueue(FAR struct usr_wqueue_s *wqueue,
         {
           /* Insert the watchdog in mid- or end-of-queue */
 
-          sq_addafter(prev, &work->sq, &wqueue->q);
+          sq_addafter(prev, &work->u.s.sq, &wqueue->q);
         }
     }
 

libs/libc/wqueue/work_usrthread.c

@@ -118,7 +118,7 @@ static void work_process(FAR struct usr_wqueue_s *wqueue)
        * zero will always execute immediately.
        */
 
-      elapsed = clock() - work->u.qtime;
+      elapsed = clock() - work->u.s.qtime;
 
       /* Is this delay work ready? */
 
@@ -173,7 +173,7 @@ static void work_process(FAR struct usr_wqueue_s *wqueue)
         }
       else
         {
-          next = work->u.qtime - clock();
+          next = work->u.s.qtime - clock();
           break;
         }
     }