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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ian Abbott <abbotti@mev.co.uk>
Subject: [PATCH 4.19 102/120] staging: comedi: me4000: Fix endian problem for AI command data
Date:   Mon, 15 Mar 2021 14:57:33 +0100
Message-Id: <20210315135723.313967845@linuxfoundation.org>
In-Reply-To: <20210315135720.002213995@linuxfoundation.org>
References: <20210315135720.002213995@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Ian Abbott <abbotti@mev.co.uk>

commit b39dfcced399d31e7c4b7341693b18e01c8f655e upstream.

The analog input subdevice supports Comedi asynchronous commands that
use Comedi's 16-bit sample format.  However, the calls to
`comedi_buf_write_samples()` are passing the address of a 32-bit integer
variable.  On bigendian machines, this will copy 2 bytes from the wrong
end of the 32-bit value.  Fix it by changing the type of the variable
holding the sample value to `unsigned short`.

Fixes: de88924f67d1 ("staging: comedi: me4000: use comedi_buf_write_samples()")
Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210223143055.257402-8-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/comedi/drivers/me4000.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/comedi/drivers/me4000.c
+++ b/drivers/staging/comedi/drivers/me4000.c
@@ -924,7 +924,7 @@ static irqreturn_t me4000_ai_isr(int irq
 	struct comedi_subdevice *s = dev->read_subdev;
 	int i;
 	int c = 0;
-	unsigned int lval;
+	unsigned short lval;
 
 	if (!dev->attached)
 		return IRQ_NONE;