wqueue: wqueue remove csection

reason:
We decouple semcount from business logic
by using an independent counting variable,
which allows us to remove critical sections in many cases.

Signed-off-by: hujun5 <[email protected]>

Author: hujun260

arch/arm/src/sama5/sam_hsmci.c

@@ -3213,8 +3213,6 @@ static void sam_callback(void *arg)
       ret = work_cancel(LPWORK, &priv->cbwork);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_cancel only returns success */
-
           lcderr("ERROR: Failed to cancel work: %d\n", ret);
         }
 
@@ -3223,8 +3221,6 @@ static void sam_callback(void *arg)
                        priv->cbarg, 0);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_queue only returns success */
-
           lcderr("ERROR: Failed to schedule work: %d\n", ret);
         }
     }

arch/arm/src/samv7/sam_hsmci.c

@@ -3353,8 +3353,6 @@ static void sam_callback(void *arg)
       ret = work_cancel(LPWORK, &priv->cbwork);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_cancel only returns success */
-
           mcerr("ERROR: Failed to cancel work: %d\n", ret);
         }
 
@@ -3363,8 +3361,6 @@ static void sam_callback(void *arg)
                        priv->cbarg, 0);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_queue only returns success */
-
           mcerr("ERROR: Failed to schedule work: %d\n", ret);
         }
     }

fs/mount/fs_automount.c

@@ -658,8 +658,6 @@ static void automount_timeout(wdparm_t arg)
   ret = work_queue(LPWORK, &priv->work, automount_worker, priv, 0);
   if (ret < 0)
     {
-      /* NOTE: Currently, work_queue only returns success */
-
       ferr("ERROR: Failed to schedule work: %d\n", ret);
     }
 }
@@ -771,8 +769,6 @@ static int automount_interrupt(FAR const struct automount_lower_s *lower,
                    priv->lower->ddelay);
   if (ret < 0)
     {
-      /* NOTE: Currently, work_queue only returns success */
-
       ferr("ERROR: Failed to schedule work: %d\n", ret);
     }
   else
@@ -840,8 +836,6 @@ FAR void *automount_initialize(FAR const struct automount_lower_s *lower)
                    priv->lower->ddelay);
   if (ret < 0)
     {
-      /* NOTE: Currently, work_queue only returns success */
-
       ferr("ERROR: Failed to schedule work: %d\n", ret);
     }
 

sched/wqueue/kwork_cancel.c

@@ -58,23 +58,20 @@ static int work_qcancel(FAR struct kwork_wqueue_s *wqueue, bool sync,
    * new work is typically added to the work queue from interrupt handlers.
    */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_wqueue_lock);
   if (work->worker != NULL)
     {
       /* Remove the entry from the work queue and make sure that it is
        * marked as available (i.e., the worker field is nullified).
        */
 
-      if (WDOG_ISACTIVE(&work->u.timer))
-        {
-          wd_cancel(&work->u.timer);
-        }
-      else
+      work->worker = NULL;
+      wd_cancel(&work->u.timer);
+      if (dq_inqueue((FAR dq_entry_t *)work, &wqueue->q))
         {
           dq_rem((FAR dq_entry_t *)work, &wqueue->q);
         }
 
-      work->worker = NULL;
       ret = OK;
     }
   else if (!up_interrupt_context() && !sched_idletask() && sync)
@@ -86,14 +83,15 @@ static int work_qcancel(FAR struct kwork_wqueue_s *wqueue, bool sync,
           if (wqueue->worker[wndx].work == work &&
               wqueue->worker[wndx].pid != nxsched_gettid())
             {
+              wqueue->worker[wndx].wait_count--;
+              spin_unlock_irqrestore(&g_wqueue_lock, flags);
               nxsem_wait_uninterruptible(&wqueue->worker[wndx].wait);
-              ret = 1;
-              break;
+              return 1;
             }
         }
     }
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_wqueue_lock, flags);
   return ret;
 }
 

sched/wqueue/kwork_notifier.c

@@ -87,6 +87,8 @@ static dq_queue_t g_notifier_free;
 
 static dq_queue_t g_notifier_pending;
 
+static spinlock_t g_work_notifier_lock;
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -166,17 +168,21 @@ static void work_notifier_worker(FAR void *arg)
 
   /* Disable interrupts very briefly. */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
 
   /* Remove the notification from the pending list */
 
-  dq_rem(&notifier->entry, &g_notifier_pending);
+  notifier = work_notifier_find(notifier->key);
+  if (notifier != NULL)
+    {
+      dq_rem(&notifier->entry, &g_notifier_pending);
 
-  /* Put the notification to the free list */
+      /* Put the notification to the free list */
 
-  dq_addlast(&notifier->entry, &g_notifier_free);
+      dq_addlast(&notifier->entry, &g_notifier_free);
+    }
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 }
 
 /****************************************************************************
@@ -213,14 +219,14 @@ int work_notifier_setup(FAR struct work_notifier_s *info)
 
   /* Disable interrupts very briefly. */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
 
   /* Try to get the entry from the free list */
 
   notifier = (FAR struct work_notifier_entry_s *)
     dq_remfirst(&g_notifier_free);
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 
   if (notifier == NULL)
     {
@@ -245,7 +251,7 @@ int work_notifier_setup(FAR struct work_notifier_s *info)
 
       /* Disable interrupts very briefly. */
 
-      flags = enter_critical_section();
+      flags = spin_lock_irqsave(&g_work_notifier_lock);
 
       /* Generate a unique key for this notification */
 
@@ -262,7 +268,7 @@ int work_notifier_setup(FAR struct work_notifier_s *info)
       dq_addlast(&notifier->entry, &g_notifier_pending);
       ret = notifier->key;
 
-      leave_critical_section(flags);
+      spin_unlock_irqrestore(&g_work_notifier_lock, flags);
     }
 
   return ret;
@@ -293,7 +299,7 @@ void work_notifier_teardown(int key)
 
   /* Disable interrupts very briefly. */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
 
   /* Find the entry matching this key in the g_notifier_pending list.  We
    * assume that there is only one.
@@ -304,19 +310,18 @@ void work_notifier_teardown(int key)
     {
       /* Cancel the work, this may be waiting */
 
-      if (work_cancel_sync(notifier->info.qid, &notifier->work) != 1)
-        {
-          /* Remove the notification from the pending list */
+      work_cancel(notifier->info.qid, &notifier->work);
 
-          dq_rem(&notifier->entry, &g_notifier_pending);
+      /* Remove the notification from the pending list */
 
-          /* Put the notification to the free list */
+      dq_rem(&notifier->entry, &g_notifier_pending);
 
-          dq_addlast(&notifier->entry, &g_notifier_free);
-        }
+      /* Put the notification to the free list */
+
+      dq_addlast(&notifier->entry, &g_notifier_free);
     }
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 }
 
 /****************************************************************************
@@ -352,7 +357,7 @@ void work_notifier_signal(enum work_evtype_e evtype,
    * the notifications have been sent.
    */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
   sched_lock();
 
   /* Process the notification at the head of the pending list until the
@@ -397,7 +402,7 @@ void work_notifier_signal(enum work_evtype_e evtype,
     }
 
   sched_unlock();
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 }
 
 #endif /* CONFIG_WQUEUE_NOTIFIER */

sched/wqueue/kwork_queue.c

@@ -47,11 +47,10 @@
 #define queue_work(wqueue, work) \
   do \
     { \
-      int sem_count; \
       dq_addlast((FAR dq_entry_t *)(work), &(wqueue)->q); \
-      nxsem_get_value(&(wqueue)->sem, &sem_count); \
-      if (sem_count < 0) /* There are threads waiting for sem. */ \
+      if ((wqueue)->wait_count < 0) /* There are threads waiting for sem. */ \
         { \
+          (wqueue)->wait_count++; \
           nxsem_post(&(wqueue)->sem); \
         } \
     } \
@@ -68,24 +67,28 @@
 static void work_timer_expiry(wdparm_t arg)
 {
   FAR struct work_s *work = (FAR struct work_s *)arg;
-  irqstate_t flags = enter_critical_section();
+  irqstate_t flags = spin_lock_irqsave(&g_wqueue_lock);
 
-  queue_work(work->wq, work);
-  leave_critical_section(flags);
+  /* We have being canceled */
+
+  if (work->worker != NULL)
+    {
+      queue_work(work->wq, work);
+    }
+
+  spin_unlock_irqrestore(&g_wqueue_lock, flags);
 }
 
 static bool work_is_canceling(FAR struct kworker_s *kworkers, int nthreads,
                               FAR struct work_s *work)
 {
-  int semcount;
   int wndx;
 
   for (wndx = 0; wndx < nthreads; wndx++)
     {
       if (kworkers[wndx].work == work)
         {
-          nxsem_get_value(&kworkers[wndx].wait, &semcount);
-          if (semcount < 0)
+          if (kworkers[wndx].wait_count < 0)
             {
               return true;
             }
@@ -145,13 +148,22 @@ int work_queue_wq(FAR struct kwork_wqueue_s *wqueue,
    * task logic or from interrupt handling logic.
    */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_wqueue_lock);
 
   /* Remove the entry from the timer and work queue. */
 
   if (work->worker != NULL)
     {
-      work_cancel_wq(wqueue, work);
+      /* Remove the entry from the work queue and make sure that it is
+       * marked as available (i.e., the worker field is nullified).
+       */
+
+      work->worker = NULL;
+      wd_cancel(&work->u.timer);
+      if (dq_inqueue((FAR dq_entry_t *)work, &wqueue->q))
+        {
+          dq_rem((FAR dq_entry_t *)work, &wqueue->q);
+        }
     }
 
   if (work_is_canceling(wqueue->worker, wqueue->nthreads, work))
@@ -177,7 +189,7 @@ int work_queue_wq(FAR struct kwork_wqueue_s *wqueue,
     }
 
 out:
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_wqueue_lock, flags);
   return ret;
 }
 

sched/wqueue/kwork_thread.c

@@ -104,6 +104,8 @@ struct lp_wqueue_s g_lpwork =
 
 #endif /* CONFIG_SCHED_LPWORK */
 
+spinlock_t g_wqueue_lock = SP_UNLOCKED;
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -138,7 +140,6 @@ static int work_thread(int argc, FAR char *argv[])
   worker_t worker;
   irqstate_t flags;
   FAR void *arg;
-  int semcount;
 
   /* Get the handle from argv */
 
@@ -147,7 +148,7 @@ static int work_thread(int argc, FAR char *argv[])
   kworker = (FAR struct kworker_s *)
             ((uintptr_t)strtoul(argv[2], NULL, 16));
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_wqueue_lock);
 
   /* Loop forever */
 
@@ -189,19 +190,19 @@ static int work_thread(int argc, FAR char *argv[])
            * performed... we don't have any idea how long this will take!
            */
 
-          leave_critical_section(flags);
+          spin_unlock_irqrestore(&g_wqueue_lock, flags);
           CALL_WORKER(worker, arg);
-          flags = enter_critical_section();
+          flags = spin_lock_irqsave(&g_wqueue_lock);
 
           /* Mark the thread un-busy */
 
           kworker->work = NULL;
 
           /* Check if someone is waiting, if so, wakeup it */
 
-          nxsem_get_value(&kworker->wait, &semcount);
-          while (semcount++ < 0)
+          while (kworker->wait_count < 0)
             {
+              kworker->wait_count++;
               nxsem_post(&kworker->wait);
             }
         }
@@ -211,10 +212,13 @@ static int work_thread(int argc, FAR char *argv[])
        * posted.
        */
 
+      wqueue->wait_count--;
+      spin_unlock_irqrestore(&g_wqueue_lock, flags);
       nxsem_wait_uninterruptible(&wqueue->sem);
+      flags = spin_lock_irqsave(&g_wqueue_lock);
     }
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_wqueue_lock, flags);
 
   nxsem_post(&wqueue->exsem);
   return OK;
@@ -276,6 +280,7 @@ static int work_thread_create(FAR const char *name, int priority,
         }
 
       wqueue->worker[wndx].pid = pid;
+      wqueue->worker[wndx].wait_count = 0;
     }
 
   sched_unlock();
@@ -334,6 +339,7 @@ FAR struct kwork_wqueue_s *work_queue_create(FAR const char *name,
   nxsem_init(&wqueue->sem, 0, 0);
   nxsem_init(&wqueue->exsem, 0, 0);
   wqueue->nthreads = nthreads;
+  wqueue->wait_count = 0;
 
   /* Create the work queue thread pool */