comedi: comedi_test: Prevent timers rescheduling during deletion

The comedi_test devices have a couple of timers (ai_timer and ao_timer)
that can be started to simulate hardware interrupts. Their expiry
functions normally reschedule the timer. The driver code calls either
del_timer_sync() or del_timer() to delete the timers from the queue, but
does not currently prevent the timers from rescheduling themselves so
synchronized deletion may be ineffective.

Add a couple of boolean members (one for each timer: ai_timer_enable and
ao_timer_enable) to the device private data structure to indicate
whether the timers are allowed to reschedule themselves. Set the member
to true when adding the timer to the queue, and to false when deleting
the timer from the queue in the waveform_ai_cancel() and
waveform_ao_cancel() functions.

The del_timer_sync() function is also called from the waveform_detach()
function, but the timer enable members will already be set to false when
that function is called, so no change is needed there.

Fixes: 403fe7f34e33 ("staging: comedi: comedi_test: fix timer race conditions")
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20240214100747.16203-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

comedi: make all 'class' structures const

Now that the driver core allows for struct class to be in read-only
memory, making all 'class' structures to be declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Ivan Orlov <ivan.orlov0322@gmail.com>
Cc: Xuezhi Zhang <zhangxuezhi1@coolpad.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230620144137.581406-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something. So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20230313181843.1207845-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

comedi: Move the main COMEDI headers

Move the main COMEDI driver headers out of "drivers/comedi/" into new
directory "include/linux/comedi/". These are "comedidev.h",
"comedilib.h", "comedi_pci.h", "comedi_pcmcia.h", and "comedi_usb.h".
Additionally, move the user-space API header "comedi.h" into
"include/uapi/linux/" and add "WITH Linux-syscall-note" to its
SPDX-License-Identifier.

Update the "COMEDI DRIVERS" section of the MAINTAINERS file to account
for these changes.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20211117120604.117740-2-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: comedi: move out of staging directory

The comedi code came into the kernel back in 2008, but traces its
lifetime to much much earlier. It's been polished and buffed and
there's really nothing preventing it from being part of the "real"
portion of the kernel.

So move it to drivers/comedi/ as it belongs there.

Many thanks to the hundreds of developers who did the work to make this
happen.

Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Link: https://lore.kernel.org/r/YHauop4u3sP6lz8j@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>