staging: comedi: pcl726: Use 16-bit 0 for interrupt data

The pcl726 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/20210223143055.257402-15-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2021-02-23 14:30:55 +00:00 committed by Greg Kroah-Hartman
parent 5ff1c08c28
commit fd3ce6557d

View File

@ -220,9 +220,11 @@ static irqreturn_t pcl726_interrupt(int irq, void *d)
struct pcl726_private *devpriv = dev->private;
if (devpriv->cmd_running) {
unsigned short val = 0;
pcl726_intr_cancel(dev, s);
comedi_buf_write_samples(s, &s->state, 1);
comedi_buf_write_samples(s, &val, 1);
comedi_handle_events(dev, s);
}