Patch "iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values" has been added to the 4.10-stable tree

Patch "iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values" has been added to the 4.10-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values

to the 4.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iio-core-fix-iio_val_fractional_log2-for-negative-values.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7fd6592d1287046f61bfd3cda3c03cd35be490f7 Mon Sep 17 00:00:00 2001
From: Nikolaus Schulz <nikolaus.schulz@avionic-design.de>
Date: Fri, 24 Mar 2017 13:41:51 +0100
Subject: iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values

From: Nikolaus Schulz <nikolaus.schulz@avionic-design.de>

commit 7fd6592d1287046f61bfd3cda3c03cd35be490f7 upstream.

Fix formatting of negative values of type IIO_VAL_FRACTIONAL_LOG2 by
switching from do_div(), which can't handle negative numbers, to
div_s64_rem().  Also use shift_right for shifting, which is safe with
negative values.

Signed-off-by: Nikolaus Schulz <nikolaus.schulz@avionic-design.de>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iio/industrialio-core.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -608,10 +608,9 @@ static ssize_t __iio_format_value(char *
 		tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
 		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
 	case IIO_VAL_FRACTIONAL_LOG2:
-		tmp = (s64)vals[0] * 1000000000LL >> vals[1];
-		tmp1 = do_div(tmp, 1000000000LL);
-		tmp0 = tmp;
-		return snprintf(buf, len, "%d.%09u", tmp0, tmp1);
+		tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
+		tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
+		return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
 	case IIO_VAL_INT_MULTIPLE:
 	{
 		int i;


Patches currently in stable-queue which might be from nikolaus.schulz@avionic-design.de are

queue-4.10/iio-core-fix-iio_val_fractional_log2-for-negative-values.patch