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

Eric Biggers
2024-12-21T09:11:35Z

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)
--
2.47.1