Re: [PATCH v2 21/29] crypto: s390/aes-gcm - use the new scatterwalk functions

Harald Freudenberger
2025-01-08T15:06:30Z

On 2024-12-30 01:14, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> Use scatterwalk_next() which consolidates scatterwalk_clamp() and
> scatterwalk_map(). Use scatterwalk_done_src() and
> scatterwalk_done_dst() which consolidate scatterwalk_unmap(),
> scatterwalk_advance(), and scatterwalk_done().
>
> Besides the new functions being a bit easier to use, this is necessary
> because scatterwalk_done() is planned to be removed.
>
> Cc: Harald Freudenberger <freude@linux.ibm.com>
> Cc: Holger Dengler <dengler@linux.ibm.com>
> Cc: linux-s390@vger.kernel.org
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>
> This patch is part of a long series touching many files, so I have
> limited the Cc list on the full series. If you want the full series
> and
> did not receive it, please retrieve it from lore.kernel.org.
>
> arch/s390/crypto/aes_s390.c | 33 +++++++++++++--------------------
> 1 file changed, 13 insertions(+), 20 deletions(-)
>
> diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
> index 9c46b1b630b1..7fd303df05ab 100644
> --- a/arch/s390/crypto/aes_s390.c
> +++ b/arch/s390/crypto/aes_s390.c
> @@ -785,32 +785,25 @@ static void gcm_walk_start(struct gcm_sg_walk
> *gw, struct scatterlist *sg,
> scatterwalk_start(&gw->walk, sg);
> }
>
> static inline unsigned int _gcm_sg_clamp_and_map(struct gcm_sg_walk
> *gw)
> {
> - struct scatterlist *nextsg;
> -
> - gw->walk_bytes = scatterwalk_clamp(&gw->walk, gw->walk_bytes_remain);
> - while (!gw->walk_bytes) {
> - nextsg = sg_next(gw->walk.sg);
> - if (!nextsg)
> - return 0;
> - scatterwalk_start(&gw->walk, nextsg);
> - gw->walk_bytes = scatterwalk_clamp(&gw->walk,
> - gw->walk_bytes_remain);
> - }
> - gw->walk_ptr = scatterwalk_map(&gw->walk);
> + if (gw->walk_bytes_remain == 0)
> + return 0;
> + gw->walk_ptr = scatterwalk_next(&gw->walk, gw->walk_bytes_remain,
> + &gw->walk_bytes);
> return gw->walk_bytes;
> }
>
> static inline void _gcm_sg_unmap_and_advance(struct gcm_sg_walk *gw,
> - unsigned int nbytes)
> + unsigned int nbytes, bool out)
> {
> gw->walk_bytes_remain -= nbytes;
> - scatterwalk_unmap(gw->walk_ptr);
> - scatterwalk_advance(&gw->walk, nbytes);
> - scatterwalk_done(&gw->walk, 0, gw->walk_bytes_remain);
> + if (out)
> + scatterwalk_done_dst(&gw->walk, gw->walk_ptr, nbytes);
> + else
> + scatterwalk_done_src(&gw->walk, gw->walk_ptr, nbytes);
> gw->walk_ptr = NULL;
> }
>
> static int gcm_in_walk_go(struct gcm_sg_walk *gw, unsigned int
> minbytesneeded)
> {
> @@ -842,11 +835,11 @@ static int gcm_in_walk_go(struct gcm_sg_walk
> *gw, unsigned int minbytesneeded)
>
> while (1) {
> n = min(gw->walk_bytes, AES_BLOCK_SIZE - gw->buf_bytes);
> memcpy(gw->buf + gw->buf_bytes, gw->walk_ptr, n);
> gw->buf_bytes += n;
> - _gcm_sg_unmap_and_advance(gw, n);
> + _gcm_sg_unmap_and_advance(gw, n, false);
> if (gw->buf_bytes >= minbytesneeded) {
> gw->ptr = gw->buf;
> gw->nbytes = gw->buf_bytes;
> goto out;
> }
> @@ -902,11 +895,11 @@ static int gcm_in_walk_done(struct gcm_sg_walk
> *gw, unsigned int bytesdone)
> memmove(gw->buf, gw->buf + bytesdone, n);
> gw->buf_bytes = n;
> } else
> gw->buf_bytes = 0;
> } else
> - _gcm_sg_unmap_and_advance(gw, bytesdone);
> + _gcm_sg_unmap_and_advance(gw, bytesdone, false);
>
> return bytesdone;
> }
>
> static int gcm_out_walk_done(struct gcm_sg_walk *gw, unsigned int
> bytesdone)
> @@ -920,14 +913,14 @@ static int gcm_out_walk_done(struct gcm_sg_walk
> *gw, unsigned int bytesdone)
> for (i = 0; i < bytesdone; i += n) {
> if (!_gcm_sg_clamp_and_map(gw))
> return i;
> n = min(gw->walk_bytes, bytesdone - i);
> memcpy(gw->walk_ptr, gw->buf + i, n);
> - _gcm_sg_unmap_and_advance(gw, n);
> + _gcm_sg_unmap_and_advance(gw, n, true);
> }
> } else
> - _gcm_sg_unmap_and_advance(gw, bytesdone);
> + _gcm_sg_unmap_and_advance(gw, bytesdone, true);
>
> return bytesdone;
> }
>
> static int gcm_aes_crypt(struct aead_request *req, unsigned int flags)

Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Tested-by: Harald Freudenberger <freude@linux.ibm.com>