`do_bufinfo_ioctl()` handled the `COMEDI_BUFINFO` ioctl. It is supposed
to update the read or write positions in the buffer depending on the
direction of data transfer set up by the asynchronous command.
Currently it checks the `SDF_CMD_READ` and `SDF_CMD_WRITE` subdevice
flags. That's fine for most subdevices - the ones that only support one
direction, but is incorrect for those subdevices that allow the command
to be set up in either direction. Since we now set the `CMDF_WRITE`
flag according to the data transfer direction of the current command
running on the subdevice, check that flag instead.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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