Patch "iio: adc: xilinx: use devm_krealloc() instead of kfree() + kcalloc()" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    iio: adc: xilinx: use devm_krealloc() instead of kfree() + kcalloc()

to the 5.10-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-adc-xilinx-use-devm_krealloc-instead-of-kfree-kc.patch
and it can be found in the queue-5.10 subdirectory.

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



commit 49dbe0191303691b44cd796ff0855a4833f6c79d
Author: Bartosz Golaszewski <brgl@xxxxxxxx>
Date:   Mon Nov 30 15:27:58 2020 +0100

    iio: adc: xilinx: use devm_krealloc() instead of kfree() + kcalloc()
    
    [ Upstream commit eab64715709ed440d54cac42f239e2d49df26c1f ]
    
    We now have devm_krealloc() in the kernel Use it indstead of calling
    kfree() and kcalloc() separately.
    
    Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
    Tested-by: Anand Ashok Dumbre <anandash@xxxxxxxxxx>
    Reviewed-by: Anand Ashok Dumbre <anandash@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20201130142759.28216-3-brgl@xxxxxxxx
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Stable-dep-of: 8d6b3ea4d9ea ("iio: adc: xilinx-xadc: Don't clobber preset voltage/temperature thresholds")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index 8494eb424b331..6f89a97bb127b 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/overflow.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
@@ -585,15 +586,22 @@ static int xadc_update_scan_mode(struct iio_dev *indio_dev,
 	const unsigned long *mask)
 {
 	struct xadc *xadc = iio_priv(indio_dev);
-	unsigned int n;
+	size_t new_size, n;
+	void *data;
 
 	n = bitmap_weight(mask, indio_dev->masklength);
 
-	kfree(xadc->data);
-	xadc->data = kcalloc(n, sizeof(*xadc->data), GFP_KERNEL);
-	if (!xadc->data)
+	if (check_mul_overflow(n, sizeof(*xadc->data), &new_size))
+		return -ENOMEM;
+
+	data = devm_krealloc(indio_dev->dev.parent, xadc->data,
+			     new_size, GFP_KERNEL);
+	if (!data)
 		return -ENOMEM;
 
+	memset(data, 0, new_size);
+	xadc->data = data;
+
 	return 0;
 }
 
@@ -1372,7 +1380,6 @@ static int xadc_remove(struct platform_device *pdev)
 	free_irq(xadc->irq, indio_dev);
 	cancel_delayed_work_sync(&xadc->zynq_unmask_work);
 	clk_disable_unprepare(xadc->clk);
-	kfree(xadc->data);
 
 	return 0;
 }