[PATCH net-next v3 06/10] crypto: af_alg: Use extract_iter_to_sg() to create scatterlists

From: David Howells
Date: Tue Jun 06 2023 - 09:11:38 EST


Use extract_iter_to_sg() to decant the destination iterator into a
scatterlist in af_alg_get_rsgl(). af_alg_make_sg() can then be removed.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
cc: Eric Dumazet <edumazet@xxxxxxxxxx>
cc: Jakub Kicinski <kuba@xxxxxxxxxx>
cc: Paolo Abeni <pabeni@xxxxxxxxxx>
cc: Jens Axboe <axboe@xxxxxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: linux-crypto@xxxxxxxxxxxxxxx
cc: netdev@xxxxxxxxxxxxxxx
---

Notes:
ver #2)
- Fix some checkpatch warnings.

crypto/af_alg.c | 57 +++++++++++------------------------------
crypto/algif_aead.c | 16 +++++++-----
crypto/algif_hash.c | 18 +++++++++----
crypto/algif_skcipher.c | 2 +-
include/crypto/if_alg.h | 6 ++---
5 files changed, 40 insertions(+), 59 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 7caff10df643..b8bf6d8525ba 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -531,45 +531,11 @@ static const struct net_proto_family alg_family = {
.owner = THIS_MODULE,
};

-int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
-{
- struct page **pages = sgl->pages;
- size_t off;
- ssize_t n;
- int npages, i;
-
- n = iov_iter_extract_pages(iter, &pages, len, ALG_MAX_PAGES, 0, &off);
- if (n < 0)
- return n;
-
- sgl->need_unpin = iov_iter_extract_will_pin(iter);
-
- npages = DIV_ROUND_UP(off + n, PAGE_SIZE);
- if (WARN_ON(npages == 0))
- return -EINVAL;
- /* Add one extra for linking */
- sg_init_table(sgl->sg, npages + 1);
-
- for (i = 0, len = n; i < npages; i++) {
- int plen = min_t(int, len, PAGE_SIZE - off);
-
- sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
-
- off = 0;
- len -= plen;
- }
- sg_mark_end(sgl->sg + npages - 1);
- sgl->npages = npages;
-
- return n;
-}
-EXPORT_SYMBOL_GPL(af_alg_make_sg);
-
static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
struct af_alg_sgl *sgl_new)
{
- sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
- sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
+ sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1);
+ sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1, sgl_new->sgt.sgl);
}

void af_alg_free_sg(struct af_alg_sgl *sgl)
@@ -577,8 +543,8 @@ void af_alg_free_sg(struct af_alg_sgl *sgl)
int i;

if (sgl->need_unpin)
- for (i = 0; i < sgl->npages; i++)
- unpin_user_page(sgl->pages[i]);
+ for (i = 0; i < sgl->sgt.nents; i++)
+ unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
}
EXPORT_SYMBOL_GPL(af_alg_free_sg);

@@ -1292,8 +1258,8 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,

while (maxsize > len && msg_data_left(msg)) {
struct af_alg_rsgl *rsgl;
+ ssize_t err;
size_t seglen;
- int err;

/* limit the amount of readable buffers */
if (!af_alg_readable(sk))
@@ -1310,16 +1276,23 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
return -ENOMEM;
}

- rsgl->sgl.npages = 0;
+ rsgl->sgl.sgt.sgl = rsgl->sgl.sgl;
+ rsgl->sgl.sgt.nents = 0;
+ rsgl->sgl.sgt.orig_nents = 0;
list_add_tail(&rsgl->list, &areq->rsgl_list);

- /* make one iovec available as scatterlist */
- err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
+ sg_init_table(rsgl->sgl.sgt.sgl, ALG_MAX_PAGES);
+ err = extract_iter_to_sg(&msg->msg_iter, seglen, &rsgl->sgl.sgt,
+ ALG_MAX_PAGES, 0);
if (err < 0) {
rsgl->sg_num_bytes = 0;
return err;
}

+ sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1);
+ rsgl->sgl.need_unpin =
+ iov_iter_extract_will_pin(&msg->msg_iter);
+
/* chain the new scatterlist with previous one */
if (areq->last_rsgl)
af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 42493b4d8ce4..829878025dba 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -210,7 +210,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
*/

/* Use the RX SGL as source (and destination) for crypto op. */
- rsgl_src = areq->first_rsgl.sgl.sg;
+ rsgl_src = areq->first_rsgl.sgl.sgt.sgl;

if (ctx->enc) {
/*
@@ -224,7 +224,8 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
* RX SGL: AAD || PT || Tag
*/
err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
- areq->first_rsgl.sgl.sg, processed);
+ areq->first_rsgl.sgl.sgt.sgl,
+ processed);
if (err)
goto free;
af_alg_pull_tsgl(sk, processed, NULL, 0);
@@ -242,7 +243,8 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,

/* Copy AAD || CT to RX SGL buffer for in-place operation. */
err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
- areq->first_rsgl.sgl.sg, outlen);
+ areq->first_rsgl.sgl.sgt.sgl,
+ outlen);
if (err)
goto free;

@@ -267,10 +269,10 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
if (usedpages) {
/* RX SGL present */
struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
+ struct scatterlist *sg = sgl_prev->sgt.sgl;

- sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
- sg_chain(sgl_prev->sg, sgl_prev->npages + 1,
- areq->tsgl);
+ sg_unmark_end(sg + sgl_prev->sgt.nents - 1);
+ sg_chain(sg, sgl_prev->sgt.nents + 1, areq->tsgl);
} else
/* no RX SGL present (e.g. authentication only) */
rsgl_src = areq->tsgl;
@@ -278,7 +280,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,

/* Initialize the crypto operation */
aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
- areq->first_rsgl.sgl.sg, used, ctx->iv);
+ areq->first_rsgl.sgl.sgt.sgl, used, ctx->iv);
aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
aead_request_set_tfm(&areq->cra_u.aead_req, tfm);

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 63af72e19fa8..16c69c4b9c62 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -91,13 +91,21 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
if (len > limit)
len = limit;

- len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);
+ ctx->sgl.sgt.sgl = ctx->sgl.sgl;
+ ctx->sgl.sgt.nents = 0;
+ ctx->sgl.sgt.orig_nents = 0;
+
+ len = extract_iter_to_sg(&msg->msg_iter, len, &ctx->sgl.sgt,
+ ALG_MAX_PAGES, 0);
if (len < 0) {
err = copied ? 0 : len;
goto unlock;
}
+ sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents);
+
+ ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter);

- ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);
+ ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl, NULL, len);

err = crypto_wait_req(crypto_ahash_update(&ctx->req),
&ctx->wait);
@@ -141,8 +149,8 @@ static ssize_t hash_sendpage(struct socket *sock, struct page *page,
flags |= MSG_MORE;

lock_sock(sk);
- sg_init_table(ctx->sgl.sg, 1);
- sg_set_page(ctx->sgl.sg, page, size, offset);
+ sg_init_table(ctx->sgl.sgl, 1);
+ sg_set_page(ctx->sgl.sgl, page, size, offset);

if (!(flags & MSG_MORE)) {
err = hash_alloc_result(sk, ctx);
@@ -151,7 +159,7 @@ static ssize_t hash_sendpage(struct socket *sock, struct page *page,
} else if (!ctx->more)
hash_free_result(sk, ctx);

- ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
+ ahash_request_set_crypt(&ctx->req, ctx->sgl.sgl, ctx->result, size);

if (!(flags & MSG_MORE)) {
if (ctx->more)
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index ee8890ee8f33..a251cd6bd5b9 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -105,7 +105,7 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
/* Initialize the crypto operation */
skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm);
skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl,
- areq->first_rsgl.sgl.sg, len, ctx->iv);
+ areq->first_rsgl.sgl.sgt.sgl, len, ctx->iv);

if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) {
/* AIO operation */
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 46494b33f5bc..34224e77f5a2 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -56,9 +56,8 @@ struct af_alg_type {
};

struct af_alg_sgl {
- struct scatterlist sg[ALG_MAX_PAGES + 1];
- struct page *pages[ALG_MAX_PAGES];
- unsigned int npages;
+ struct sg_table sgt;
+ struct scatterlist sgl[ALG_MAX_PAGES + 1];
bool need_unpin;
};

@@ -164,7 +163,6 @@ int af_alg_release(struct socket *sock);
void af_alg_release_parent(struct sock *sk);
int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern);

-int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len);
void af_alg_free_sg(struct af_alg_sgl *sgl);

static inline struct alg_sock *alg_sk(struct sock *sk)