[PATCH 14/14] staging: comedi: pcl726: Use 16-bit 0 for interrupt data

Ian Abbott abbotti at mev.co.uk
Tue Feb 23 14:30:55 UTC 2021


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 at mev.co.uk>
---
 drivers/staging/comedi/drivers/pcl726.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/drivers/pcl726.c b/drivers/staging/comedi/drivers/pcl726.c
index 64eb649c9813..88f25d7e76f7 100644
--- a/drivers/staging/comedi/drivers/pcl726.c
+++ b/drivers/staging/comedi/drivers/pcl726.c
@@ -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);
 	}
 
-- 
2.30.0



More information about the devel mailing list