[incubator-nuttx] 02/02: sched: semaphore: Remove a redundant critical section in nxsem_tickwait()

[xi...@apache.org]

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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git

commit 7758f3dcb1dcf61e9280aaba6cc98668e6c3bc65
Author: Masayuki Ishikawa <ma...@gmail.com>
AuthorDate: Wed Mar 17 08:33:57 2021 +0900

    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 <Ma...@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 ef90a89..15e7f18 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;
-    }
-
-  /* We can now restore interrupts */
-
-  /* Success exits */
-
-success_with_irqdisabled:
-
-  /* Error exits */
+out:
 
-errout_with_irqdisabled:
-  leave_critical_section(flags);
   return ret;
 }