drivers/comedi: use standard array-copy-function

comedi_fops.c utilizes memdup_user() to copy a userspace array.

The new function memdup_array_user() provides a standardized way to copy
userspace-arrays. It makes it easier to see that an array is being
copied and, additionally, performs a generic overflow-check which might
help make the code more robust in case of changes in the future.

Replace memdup_user() with memdup_array_user().

Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20231103112932.75795-2-pstanner@redhat.com
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: check data length for INSN_CONFIG_GET_PWM_OUTPUT

Comedi INSN_CONFIG instructions have different expected instructtion
data lengths depending on the type of configuration instruction
specified by the first word of data. This is checked by
`check_insn_config_length()`. There are a few configuration
instructions whose data lengths are not currently checked, usually for
rare configuration instructions that are implemented differently by
different drivers. For unknown configuration instructions, the function
logs a warning and accepts the specified data length.

The `INSN_CONFIG_GET_PWM_OUTPUT` configuration instruction length is not
currently checked, but all the places it is currently used expect a data
length of 3. (These places are `ni_get_pwm_config()` in
"ni_mio_common.c", and `pci1760_pwm_insn_config()` in "adv_pci1760.c".)
Make this length official by checking it in
`check_insn_config_length()`.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20230103151127.19287-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

comedi: convert sysfs snprintf to sysfs_emit

Follow the advice of the Documentation/filesystems/sysfs.rst
and show() should only use sysfs_emit() or sysfs_emit_at()
when formatting the value to be returned to user space.

Signed-off-by: Xuezhi Zhang <zhangxuezhi1@coolpad.com>
Link: https://lore.kernel.org/r/20220901013423.418464-1-zhangxuezhi3@gmail.com
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>

comedi: Fix memory leak in compat_insnlist()

`compat_insnlist()` handles the 32-bit version of the `COMEDI_INSNLIST`
ioctl (whenwhen `CONFIG_COMPAT` is enabled). It allocates memory to
temporarily hold an array of `struct comedi_insn` converted from the
32-bit version in user space. This memory is only being freed if there
is a fault while filling the array, otherwise it is leaked.

Add a call to `kfree()` to fix the leak.

Fixes: b8d47d881305 ("comedi: get rid of compat_alloc_user_space() mess in COMEDI_INSNLIST compat")
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-staging@lists.linux.dev
Cc: <stable@vger.kernel.org> # 5.13+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210916145023.157479-1-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>