ASoC: cs-amp-lib: Fix wrong sizeof() in _cs_amp_set_efi_calibration_data()

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Instead of changing to sizeof(*data) it has been replaced by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")
Link: https://patch.msgid.link/20260521122511.987322-2-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/cs-amp-lib.c b/sound/soc/codecs/cs-amp-lib.c
index b34b1f5f121f322fec96cb57cc6d0c823180f07e..881c6f2264f341a42fc5a0ed3cf135661e30b416 100644 (file)
--- 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? */