From 8536749d4952649ada4a88396079e6ec69c1fc9f Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@mev.co.uk>
Date: Tue, 23 Feb 2021 14:30:51 +0000
Subject: [PATCH] staging: comedi: amplc_pc236_common: Use 16-bit 0 for
interrupt data
The Amplicon PC36AT/PCI236 common 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/20210223143055.257402-11-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/staging/comedi/drivers/amplc_pc236_common.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/comedi/drivers/amplc_pc236_common.c b/drivers/staging/comedi/drivers/amplc_pc236_common.c
index 043752663188f..981d281e87a13 100644
--- a/drivers/staging/comedi/drivers/amplc_pc236_common.c
+++ b/drivers/staging/comedi/drivers/amplc_pc236_common.c
@@ -126,7 +126,9 @@ static irqreturn_t pc236_interrupt(int irq, void *d)
handled = pc236_intr_check(dev);
if (dev->attached && handled) {
- comedi_buf_write_samples(s, &s->state, 1);
+ unsigned short val = 0;
+
+ comedi_buf_write_samples(s, &val, 1);
comedi_handle_events(dev, s);
}
return IRQ_RETVAL(handled);
--
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