From 7758f3dcb1dcf61e9280aaba6cc98668e6c3bc65 Mon Sep 17 00:00:00 2001
From: Masayuki Ishikawa <masayuki.ishikawa@gmail.com>
Date: Wed, 17 Mar 2021 08:33:57 +0900
Subject: [PATCH] sched: semaphore: Remove a redundant critical section in
 nxsem_tickwait()

Summary:
- This commit removes a redundant critical section in nxsem_tickkwait()

Impact:
- None

Testing:
- Tested with ping with the following configs
- spresense:rndis, spresense:rndis_smp

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
---
 sched/semaphore/sem_tickwait.c | 33 +++++++--------------------------
 1 file changed, 7 insertions(+), 26 deletions(-)

diff --git a/sched/semaphore/sem_tickwait.c b/sched/semaphore/sem_tickwait.c
index ef90a897ed9..15e7f18ce8f 100644
--- a/sched/semaphore/sem_tickwait.c
+++ b/sched/semaphore/sem_tickwait.c
@@ -70,22 +70,16 @@
 int nxsem_tickwait(FAR sem_t *sem, clock_t start, uint32_t delay)
 {
   FAR struct tcb_s *rtcb = this_task();
-  irqstate_t flags;
   clock_t elapsed;
   int ret;
 
   DEBUGASSERT(sem != NULL && up_interrupt_context() == false);
 
-  /* We will disable interrupts until we have completed the semaphore
-   * wait.  We need to do this (as opposed to just disabling pre-emption)
-   * because there could be interrupt handlers that are asynchronously
-   * posting semaphores and to prevent race conditions with watchdog
-   * timeout.  This is not too bad because interrupts will be re-
-   * enabled while we are blocked waiting for the semaphore.
+  /* NOTE: We do not need a critical section here, because
+   * nxsem_wait() and nxsem_timeout() use a critical section
+   * in the functions.
    */
 
-  flags = enter_critical_section();
-
   /* Try to take the semaphore without waiting. */
 
   ret = nxsem_trywait(sem);
@@ -93,7 +87,7 @@ int nxsem_tickwait(FAR sem_t *sem, clock_t start, uint32_t delay)
     {
       /* We got it! */
 
-      goto success_with_irqdisabled;
+      goto out;
     }
 
   /* We will have to wait for the semaphore.  Make sure that we were provided
@@ -104,7 +98,7 @@ int nxsem_tickwait(FAR sem_t *sem, clock_t start, uint32_t delay)
     {
       /* Return the errno from nxsem_trywait() */
 
-      goto errout_with_irqdisabled;
+      goto out;
     }
 
   /* Adjust the delay for any time since the delay was calculated */
@@ -113,7 +107,7 @@ int nxsem_tickwait(FAR sem_t *sem, clock_t start, uint32_t delay)
   if (/* elapsed >= (UINT32_MAX / 2) || */ elapsed >= delay)
     {
       ret = -ETIMEDOUT;
-      goto errout_with_irqdisabled;
+      goto out;
     }
 
   delay -= elapsed;
@@ -130,21 +124,8 @@ int nxsem_tickwait(FAR sem_t *sem, clock_t start, uint32_t delay)
 
   wd_cancel(&rtcb->waitdog);
 
-  if (ret < 0)
-    {
-      goto errout_with_irqdisabled;
-    }
+out:
 
-  /* We can now restore interrupts */
-
-  /* Success exits */
-
-success_with_irqdisabled:
-
-  /* Error exits */
-
-errout_with_irqdisabled:
-  leave_critical_section(flags);
   return ret;
 }