sched_lock refine: remove sched_[un]lock in xxx_waitsample

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

arch/arm/src/sama5/sam_tsd.c

@@ -357,12 +357,8 @@ static int sam_tsd_waitsample(struct sam_tsd_s *priv,
   /* Interrupts must be disabled when this is called to (1) prevent posting
    * of semaphores from interrupt handlers, and (2) to prevent sampled data
    * from changing until it has been reported.
-   *
-   * In addition, we will also disable pre-emption to prevent other threads
-   * from getting control while we muck with the semaphores.
    */
 
-  sched_lock();
   flags = enter_critical_section();
 
   /* Now release the semaphore that manages mutually exclusive access to
@@ -408,14 +404,6 @@ static int sam_tsd_waitsample(struct sam_tsd_s *priv,
    */
 
   leave_critical_section(flags);
-
-  /* Restore pre-emption.  We might get suspended here but that is okay
-   * because we already have our sample.  Note:  this means that if there
-   * were two threads reading from the touchscreen ADC for some reason, the
-   * data might be read out of order.
-   */
-
-  sched_unlock();
   return ret;
 }
 

boards/arm/stm32/mikroe-stm32f4/src/stm32_touchscreen.c

@@ -666,12 +666,14 @@ static int tc_waitsample(struct tc_dev_s *priv,
                               struct tc_sample_s *sample)
 {
   int ret;
+  irqstate_t flags;
 
-  /* Pre-emption must be disabled when this is called to prevent sampled
-   * data from changing until it has been reported.
+  /* Interrupts must be disabled when this is called to (1) prevent posting
+   * of semaphores from interrupt handlers, and (2) to prevent sampled data
+   * from changing until it has been reported.
    */
 
-  sched_lock();
+  flags = enter_critical_section();
 
   /* Now release the mutex that manages mutually exclusive access to
    * the device structure.  This may cause other tasks to become ready to
@@ -706,13 +708,12 @@ static int tc_waitsample(struct tc_dev_s *priv,
   ret = nxmutex_lock(&priv->devlock);
 
 errout:
-  /* Restore pre-emption.  We might get suspended here but that is okay
-   * because we already have our sample.  Note:  this means that if there
-   * were two threads reading from the touchscreen for some reason, the data
-   * might be read out of order.
+  /* Then re-enable interrupts.  We might get interrupt here and there
+   * could be a new sample.  But no new threads will run because we still
+   * have pre-emption disabled.
    */
 
-  sched_unlock();
+  leave_critical_section(flags);
   return ret;
 }
 

boards/mips/pic32mx/pic32mx7mmb/src/pic32_touchscreen.c

@@ -556,11 +556,12 @@ static int tc_waitsample(struct tc_dev_s *priv,
 {
   int ret;
 
-  /* Pre-emption must be disabled when this is called to prevent sampled
-   * data from changing until it has been reported.
+  /* Interrupts must be disabled when this is called to (1) prevent posting
+   * of semaphores from interrupt handlers, and (2) to prevent sampled data
+   * from changing until it has been reported.
    */
 
-  sched_lock();
+  flags = enter_critical_section();
 
   /* Now release the mutex that manages mutually exclusive access to
    * the device structure.  This may cause other tasks to become ready to
@@ -595,13 +596,12 @@ static int tc_waitsample(struct tc_dev_s *priv,
   ret = nxmutex_lock(&priv->devlock);
 
 errout:
-  /* Restore pre-emption.  We might get suspended here but that is okay
-   * because we already have our sample.  Note:  this means that if there
-   * were two threads reading from the touchscreen for some reason, the data
-   * might be read out of order.
+  /* Then re-enable interrupts.  We might get interrupt here and there
+   * could be a new sample.  But no new threads will run because we still
+   * have pre-emption disabled.
    */
 
-  sched_unlock();
+  leave_critical_section(flags);
   return ret;
 }
 

drivers/usbhost/usbhost_hidmouse.c

@@ -1263,12 +1263,8 @@ static int usbhost_waitsample(FAR struct usbhost_state_s *priv,
   /* Interrupts must be disabled when this is called to (1) prevent posting
    * of semaphores from interrupt handlers, and (2) to prevent sampled data
    * from changing until it has been reported.
-   *
-   * In addition, we will also disable pre-emption to prevent other threads
-   * from getting control while we muck with the semaphores.
    */
 
-  sched_lock();
   flags = enter_critical_section();
 
   /* Now release the semaphore that manages mutually exclusive access to
@@ -1322,14 +1318,6 @@ static int usbhost_waitsample(FAR struct usbhost_state_s *priv,
    */
 
   leave_critical_section(flags);
-
-  /* Restore pre-emption.  We might get suspended here but that is okay
-   * because we already have our sample.  Note:  this means that if there
-   * were two threads reading from the HIDMOUSE for some reason, the data
-   * might be read out of order.
-   */
-
-  sched_unlock();
   return ret;
 }
 

drivers/usbhost/usbhost_xboxcontroller.c

@@ -960,12 +960,8 @@ static int usbhost_waitsample(FAR struct usbhost_state_s *priv,
   /* Interrupts must be disabled when this is called to (1) prevent posting
    * of semaphores from interrupt handlers, and (2) to prevent sampled data
    * from changing until it has been reported.
-   *
-   * In addition, we will also disable pre-emption to prevent other threads
-   * from getting control while we muck with the semaphores.
    */
 
-  sched_lock();
   flags = enter_critical_section();
 
   /* Now release the semaphore that manages mutually exclusive access to
@@ -1019,14 +1015,6 @@ static int usbhost_waitsample(FAR struct usbhost_state_s *priv,
    */
 
   leave_critical_section(flags);
-
-  /* Restore pre-emption.  We might get suspended here but that is okay
-   * because we already have our sample.  Note:  this means that if there
-   * were two threads reading from the HIDMOUSE for some reason, the data
-   * might be read out of order.
-   */
-
-  sched_unlock();
   return ret;
 }