Re: [PATCH] ASoC: cs-amp-lib: Replace offsetof() with struct_size()

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

On 14/04/2025 7:59 am, Thorsten Blum wrote:
> Use struct_size() to calculate the number of bytes to allocate and used
> by 'cirrus_amp_efi_data'. Compared to offsetof(), struct_size() provides
> additional compile-time checks (e.g., __must_be_array()).
> 
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> Compile-tested only
> ---
>   sound/soc/codecs/cs-amp-lib-test.c | 3 +--
>   sound/soc/codecs/cs-amp-lib.c      | 2 +-
>   2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/soc/codecs/cs-amp-lib-test.c b/sound/soc/codecs/cs-amp-lib-test.c
> index 45626f99a417..2369fffb58f7 100644
> --- a/sound/soc/codecs/cs-amp-lib-test.c
> +++ b/sound/soc/codecs/cs-amp-lib-test.c
> @@ -40,8 +40,7 @@ static void cs_amp_lib_test_init_dummy_cal_blob(struct kunit *test, int num_amps
>   	unsigned int blob_size;
>   	int i;
>   
> -	blob_size = offsetof(struct cirrus_amp_efi_data, data) +
> -		    sizeof(struct cirrus_amp_cal_data) * num_amps;
> +	blob_size = struct_size(priv->cal_blob, data, num_amps);
>   
>   	priv->cal_blob = kunit_kzalloc(test, blob_size, GFP_KERNEL);
>   	KUNIT_ASSERT_NOT_NULL(test, priv->cal_blob);
> diff --git a/sound/soc/codecs/cs-amp-lib.c b/sound/soc/codecs/cs-amp-lib.c
> index c677868c5d5f..c2ce828a96ae 100644
> --- a/sound/soc/codecs/cs-amp-lib.c
> +++ b/sound/soc/codecs/cs-amp-lib.c
> @@ -147,7 +147,7 @@ static struct cirrus_amp_efi_data *cs_amp_get_cal_efi_buffer(struct device *dev)
>   	dev_dbg(dev, "Calibration: Size=%d, Amp Count=%d\n", efi_data->size, efi_data->count);
>   
>   	if ((efi_data->count > 128) ||
> -	    offsetof(struct cirrus_amp_efi_data, data[efi_data->count]) > data_size) {
> +	    struct_size(efi_data, data, efi_data->count) > data_size) {
>   		dev_err(dev, "EFI cal variable truncated\n");
>   		ret = -EOVERFLOW;
>   		goto err;

It should include <linux/overflow.h>
Apart from that
Reviewed-by: Richard Fitzgerald <rf@opensource.cirrus.com>