Re: [PATCH] crypto: qce - simplify qce_xts_swapiv()

[Bjorn Andersson]

On Mon, Mar 30, 2026 at 07:39:25PM +0200, Thorsten Blum wrote:
> Declare 'swap' as zero-initialized and use a single index variable to
> simplify the byte-swapping loop in qce_xts_swapiv(). Add a comment for
> clarity.
> 
> Signed-off-by: Thorsten Blum <thorsten.blum@xxxxxxxxx>

Reviewed-by: Bjorn Andersson <andersson@xxxxxxxxxx>

Regards,
Bjorn

> ---
>  drivers/crypto/qce/common.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/crypto/qce/common.c b/drivers/crypto/qce/common.c
> index 04253a8d3340..54a78a57f630 100644
> --- a/drivers/crypto/qce/common.c
> +++ b/drivers/crypto/qce/common.c
> @@ -280,17 +280,17 @@ static u32 qce_encr_cfg(unsigned long flags, u32 aes_key_size)
>  #ifdef CONFIG_CRYPTO_DEV_QCE_SKCIPHER
>  static void qce_xts_swapiv(__be32 *dst, const u8 *src, unsigned int ivsize)
>  {
> -	u8 swap[QCE_AES_IV_LENGTH];
> -	u32 i, j;
> +	u8 swap[QCE_AES_IV_LENGTH] = {0};
> +	unsigned int i, offset;
>  
>  	if (ivsize > QCE_AES_IV_LENGTH)
>  		return;
>  
> -	memset(swap, 0, QCE_AES_IV_LENGTH);
> +	offset = QCE_AES_IV_LENGTH - ivsize;
>  
> -	for (i = (QCE_AES_IV_LENGTH - ivsize), j = ivsize - 1;
> -	     i < QCE_AES_IV_LENGTH; i++, j--)
> -		swap[i] = src[j];
> +	/* Reverse and right-align IV bytes. */
> +	for (i = 0; i < ivsize; i++)
> +		swap[offset + i] = src[ivsize - 1 - i];
>  
>  	qce_cpu_to_be32p_array(dst, swap, QCE_AES_IV_LENGTH);
>  }
>