releases/4.13.6/staging-iio-ad7192-fix-use-the-dedicated-reset-function-avoiding-dma-from-stack.patch

   1 From f790923f146140a261ad211e5baf75d169f16fb2 Mon Sep 17 00:00:00 2001
   2 From: Stefan Popa <stefan.popa@analog.com>
   3 Date: Thu, 14 Sep 2017 16:50:28 +0300
   4 Subject: staging: iio: ad7192: Fix - use the dedicated reset function avoiding dma from stack.
   5
   6 From: Stefan Popa <stefan.popa@analog.com>
   7
   8 commit f790923f146140a261ad211e5baf75d169f16fb2 upstream.
   9
  10 Depends on: 691c4b95d1 ("iio: ad_sigma_delta: Implement a dedicated reset function")
  11
  12 SPI host drivers can use DMA to transfer data, so the buffer should be properly allocated.
  13 Keeping it on the stack could cause an undefined behavior.
  14
  15 The dedicated reset function solves this issue.
  16
  17 Signed-off-by: Stefan Popa <stefan.popa@analog.com>
  18 Acked-by: Lars-Peter Clausen <lars@metafoo.de>
  19 Acked-by: Michael Hennerich <michael.hennerich@analog.com>
  20 Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  22
  23 ---
  24  drivers/staging/iio/adc/ad7192.c |    4 +---
  25  1 file changed, 1 insertion(+), 3 deletions(-)
  26
  27 --- a/drivers/staging/iio/adc/ad7192.c
  28 +++ b/drivers/staging/iio/adc/ad7192.c
  29 @@ -223,11 +223,9 @@ static int ad7192_setup(struct ad7192_st
  30         struct iio_dev *indio_dev = spi_get_drvdata(st->sd.spi);
  31         unsigned long long scale_uv;
  32         int i, ret, id;
  33 -       u8 ones[6];
  34
  35         /* reset the serial interface */
  36 -       memset(&ones, 0xFF, 6);
  37 -       ret = spi_write(st->sd.spi, &ones, 6);
  38 +       ret = ad_sd_reset(&st->sd, 48);
  39         if (ret < 0)
  40                 goto out;
  41         usleep_range(500, 1000); /* Wait for at least 500us */