FAILED: patch "[PATCH] iio: buffer: align the size of scan bytes to size of the" failed to apply to 4.4-stable tree

FAILED: patch "[PATCH] iio: buffer: align the size of scan bytes to size of the" failed to apply to 4.4-stable tree

[gregkh]

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;
 }
 

Re: FAILED: patch "[PATCH] iio: buffer: align the size of scan bytes to size of the" failed to apply to 4.4-stable tree

[Lars Möllendorf]

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;
>  }
>  
> 

-- 

Lars Möllendorf, B. Eng.


Tel.:    +49 (0) 7641 93500-425
Fax:     +49 (0) 7641 93500-999
E-Mail:  lars.moellendorf@plating.de <mailto:lars.moellendorf@plating.de>
Website: www.plating.de <http://www.plating.de>

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Re: FAILED: patch "[PATCH] iio: buffer: align the size of scan bytes to size of the" failed to apply to 4.4-stable tree

[Greg KH]

On Fri, Jan 24, 2020 at 11:16:06AM +0100, Lars Möllendorf wrote:
> 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.

Looks like it is needed to me, thanks for the backport, now queued up.

greg k-h