[PATCH 1/3] ASoC: cs-amp-lib: Fix wrong sizeof() in _cs_amp_set_efi_calibration_data()

[Richard Fitzgerald <rf@opensource.cirrus.com>]

When calculating data->count replace the incorrect sizeof(data) with use
of struct_offset().

The faulty sizeof(data) was incorrectly calculating the size of the
pointer instead of the size of the struct pointed to. As it happens, both
values are 8 on a 64-bit CPU. In the unlikely event of using this code on
a 32-bit CPU the number of available bytes would be calculated 4 larger
than is actually available.

Instead of changing to sizeof(*data) it has been replaced by
struct_offset() because it has better chance of detecting these sorts of
typos. Also the offset of the data[] array is actually what we want to know
here anyway.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 2b62e66626f0 ("ASoC: cs-amp-lib: Add function to write calibration to UEFI")
---
 sound/soc/codecs/cs-amp-lib.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/cs-amp-lib.c b/sound/soc/codecs/cs-amp-lib.c
index b34b1f5f121f..881c6f2264f3 100644
--- a/sound/soc/codecs/cs-amp-lib.c
+++ b/sound/soc/codecs/cs-amp-lib.c
@@ -500,7 +500,7 @@ static int _cs_amp_set_efi_calibration_data(struct device *dev, int amp_index, i
 	 * must be set.
 	 */
 	if (data->count == 0)
-		data->count = (data->size - sizeof(data)) / sizeof(data->data[0]);
+		data->count = (data->size - struct_offset(data, data)) / sizeof(data->data[0]);
 
 	if (amp_index < 0) {
 		/* Is there already a slot for this target? */
-- 
2.47.3