xiaoxiang781216 commented on a change in pull request #5204:
URL: https://github.com/apache/incubator-nuttx/pull/5204#discussion_r815352567
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File path: drivers/input/ajoystick.c
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@@ -412,45 +407,14 @@ static int ajoy_close(FAR struct file *filep)
FAR struct ajoy_open_s *curr;
FAR struct ajoy_open_s *prev;
irqstate_t flags;
- bool closing;
- int ret;
DEBUGASSERT(filep && filep->f_priv && filep->f_inode);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = (FAR struct ajoy_upperhalf_s *)inode->i_private;
- /* Handle an improbable race conditions with the following atomic test
- * and set.
- *
- * This is actually a pretty feeble attempt to handle this. The
- * improbable race condition occurs if two different threads try to
- * close the joystick driver at the same time. The rule: don't do
- * that! It is feeble because we do not really enforce stale pointer
- * detection anyway.
- */
-
flags = enter_critical_section();
- closing = opriv->ao_closing;
- opriv->ao_closing = true;
- leave_critical_section(flags);
-
- if (closing)
- {
- /* Another thread is doing the close */
-
- return OK;
- }
-
- /* Get exclusive access to the driver structure */
Review comment:
It's enough to protect the shared resource by one method. Since it's
very confuse and error prone to protect by both semaphore and critical section,
I remove au_exclsem from ajoy_upperhalf_s.
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