Here is the email loop talk about why it is better to remove the option:
https://groups.google.com/forum/#!topic/nuttx/AaNkS7oU6R0
Change-Id: Ib66c037752149ad4b2787ef447f966c77aa12aad
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
* Simplify EINTR/ECANCEL error handling
1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx
* Unify the void cast usage
1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro
include/nuttx/nx/nxcursor.h: Add a header file descrbing the implementation of an NX cursor interface. There is no implementation in place yet.
include/nuttx/video/cursor.h: Separate out cursor definitions from fb.h. Other graphic interfaces other than a framebuffer may support a cursor, possible a software cursor.
graphics/nxbe/nxbe_bitmap.c: Fix another coordinate system problem.
graphics/: Review use of device coordinate system with window frambebuffer and make fixes accordingly.
graphics/nxbe/nxbe_fill.c: Fix a coordinate system bug. Was trying to update the window fraembuffer using the device coordinate system. Need to use the relative coordinate system.
graphics/: Use DEBUGASSERT instead of return an error since the is no user to handle the errors within the NX server. Use CONFIG_DEBUG_GRAPHICS instead of CONFIG_DEBUG_FEATURES in most cases.
graphics/: Nothing under graphics/ should set the errno.
This commit backs out most of commit b4747286b1. That change was added because sem_wait() would sometimes cause cancellation points inappropriated. But with these recent changes, nxsem_wait() is used instead and it is not a cancellation point.
In the OS, all calls to sem_wait() changed to nxsem_wait(). nxsem_wait() does not return errors via errno so each place where nxsem_wait() is now called must not examine the errno variable.
In all OS functions (not libraries), change sem_wait() to nxsem_wait(). This will prevent the OS from creating bogus cancellation points and from modifying the per-task errno variable.
sched/semaphore: Add the function nxsem_wait(). This is a new internal OS interface. It is functionally equivalent to sem_wait() except that (1) it is not a cancellation point, and (2) it does not set the per-thread errno value on return.
sched/semaphore: Add nxsem_post() which is identical to sem_post() except that it never modifies the errno variable. Changed all references to sem_post in the OS to nxsem_post().
sched/semaphore: Add nxsem_destroy() which is identical to sem_destroy() except that it never modifies the errno variable. Changed all references to sem_destroy() in the OS to nxsem_destroy().
libc/semaphore and sched/semaphore: Add nxsem_getprotocol() and nxsem_setprotocola which are identical to sem_getprotocol() and set_setprotocol() except that they never modifies the errno variable. Changed all references to sem_setprotocol in the OS to nxsem_setprotocol(). sem_getprotocol() was not used in the OS
libc/semaphore: Add nxsem_getvalue() which is identical to sem_getvalue() except that it never modifies the errno variable. Changed all references to sem_getvalue in the OS to nxsem_getvalue().
sched/semaphore: Rename all internal private functions from sem_xyz to nxsem_xyz. The sem_ prefix is (will be) reserved only for the application semaphore interfaces.
libc/semaphore: Add nxsem_init() which is identical to sem_init() except that it never modifies the errno variable. Changed all references to sem_init in the OS to nxsem_init().
sched/semaphore: Rename sem_tickwait() to nxsem_tickwait() so that it is clear this is an internal OS function.
sched/semaphoate: Rename sem_reset() to nxsem_reset() so that it is clear this is an internal OS function.
net/: psock_recvfrom() is an internal interface and should not set the errno nor should it be a cancellation point.
net/: psock_accept() is not a cancellation point.
net/: psock_getsockopt() and psock_socket*9 are an internal interfaces and should not set the errno.
net/: psock_getsockopt() is an internal interface and should not set the errno.
net/: psock_listen() is an internal interface and should not set the errno.
net/: psock_connect(( is an internal interface and should not set the errno nor should it be a cancellation point.
net/: psock_bind() is an internal interface and should not set the errno.
net/: psock_accept() is an internal interface and should not set the errno.
