staging: comedi: comedi_parport: Use 16-bit 0 for interrupt data
authorIan Abbott <abbotti@mev.co.uk>
Tue, 23 Feb 2021 14:30:52 +0000 (14:30 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 10 Mar 2021 08:23:29 +0000 (09:23 +0100)
commita1acdbc55403d94ac8dddcb0311360bc6dae659f
tree1793ce77a8e492876a87b2f1f37aadc2759a00d7
parent8536749d4952649ada4a88396079e6ec69c1fc9f
staging: comedi: comedi_parport: Use 16-bit 0 for interrupt data

The comedi_parport driver has an "interrupt" subdevice that supports
Comedi asynchronous commands, placing a value in the Comedi buffer for
each interrupt.  The subdevice uses Comedi's 16-bit sample format but
the interrupt handler is calling `comedi_buf_write_samples()` with the
address of a 32-bit integer `&s->state`.  On bigendian machines, this
will copy 2 bytes from the wrong end of the 32-bit integer.  This isn't
really a problem since `s->state` will always be 0 for this subdevice,
but clean it up by using a 16-bit variable initialized to 0 to pass the
value.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-12-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/comedi/drivers/comedi_parport.c