Hi Greg,

as the author of the original patch I just mailed the backport to Stable@vger.kernel.org (and a lot of others as a result of `scripts/get_maintainer.pl` and `git send-email`).

However, I don't know if Jonathan and the other maintainers want the patch applied to the 4.4-stable tree or to any other stable or longterm tree.

Thanks, Lars

On 19.01.20 14:35, gregkh@linuxfoundation.org wrote:

The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 883f616530692d81cb70f8a32d85c0d2afc05f69 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lars=20M=C3=B6llendorf?= lars.moellendorf@plating.de Date: Fri, 13 Dec 2019 14:50:55 +0100 Subject: [PATCH] iio: buffer: align the size of scan bytes to size of the largest element MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

Previous versions of `iio_compute_scan_bytes` only aligned each element to its own length (i.e. its own natural alignment). Because multiple consecutive sets of scan elements are buffered this does not work in case the computed scan bytes do not align with the natural alignment of the first scan element in the set.

This commit fixes this by aligning the scan bytes to the natural alignment of the largest scan element in the set.

Fixes: 959d2952d124 ("staging:iio: make iio_sw_buffer_preenable much more general.") Signed-off-by: Lars Möllendorf lars.moellendorf@plating.de Reviewed-by: Lars-Peter Clausen lars@metafoo.de Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index c193d64e5217..112225c0e486 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -566,7 +566,7 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const unsigned long *mask, bool timestamp) { unsigned bytes = 0;

• int length, i;

• int length, i, largest = 0;

/* How much space will the demuxed element take? */ for_each_set_bit(i, mask, @@ -574,13 +574,17 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev, length = iio_storage_bytes_for_si(indio_dev, i); bytes = ALIGN(bytes, length); bytes += length;

• largest = max(largest, length);
  

  }

if (timestamp) { length = iio_storage_bytes_for_timestamp(indio_dev); bytes = ALIGN(bytes, length); bytes += length;

• largest = max(largest, length);
  

  }
• bytes = ALIGN(bytes, largest); return bytes;

}