crypto: af_alg/hash: Support MSG_SPLICE_PAGES

Make AF_ALG sendmsg() support MSG_SPLICE_PAGES in the hashing code.  This
causes pages to be spliced from the source iterator if possible.

This allows ->sendpage() to be replaced by something that can handle
multiple multipage folios in a single transaction.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 3cf7348..7d4b601 100644 (file)
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -542,9 +542,14 @@ void af_alg_free_sg(struct af_alg_sgl *sgl)
 {
        int i;
 
-       if (sgl->need_unpin)
-               for (i = 0; i < sgl->sgt.nents; i++)
-                       unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
+       if (sgl->sgt.sgl) {
+               if (sgl->need_unpin)
+                       for (i = 0; i < sgl->sgt.nents; i++)
+                               unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
+               if (sgl->sgt.sgl != sgl->sgl)
+                       kvfree(sgl->sgt.sgl);
+               sgl->sgt.sgl = NULL;
+       }
 }
 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 16c69c4..1a2d80c 100644 (file)
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -63,78 +63,102 @@ static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)
 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
                        size_t ignored)
 {
-       int limit = ALG_MAX_PAGES * PAGE_SIZE;
        struct sock *sk = sock->sk;
        struct alg_sock *ask = alg_sk(sk);
        struct hash_ctx *ctx = ask->private;
-       long copied = 0;
+       ssize_t copied = 0;
+       size_t len, max_pages, npages;
+       bool continuing = ctx->more, need_init = false;
        int err;
 
-       if (limit > sk->sk_sndbuf)
-               limit = sk->sk_sndbuf;
+       max_pages = min_t(size_t, ALG_MAX_PAGES,
+                         DIV_ROUND_UP(sk->sk_sndbuf, PAGE_SIZE));
 
        lock_sock(sk);
-       if (!ctx->more) {
+       if (!continuing) {
                if ((msg->msg_flags & MSG_MORE))
                        hash_free_result(sk, ctx);
-
-               err = crypto_wait_req(crypto_ahash_init(&ctx->req), &ctx->wait);
-               if (err)
-                       goto unlock;
+               need_init = true;
        }
 
        ctx->more = false;
 
        while (msg_data_left(msg)) {
-               int len = msg_data_left(msg);
-
-               if (len > limit)
-                       len = limit;
-
                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;
+               err = -EIO;
+               npages = iov_iter_npages(&msg->msg_iter, max_pages);
+               if (npages == 0)
+                       goto unlock_free;
+
+               if (npages > ARRAY_SIZE(ctx->sgl.sgl)) {
+                       err = -ENOMEM;
+                       ctx->sgl.sgt.sgl =
+                               kvmalloc(array_size(npages,
+                                                   sizeof(*ctx->sgl.sgt.sgl)),
+                                        GFP_KERNEL);
+                       if (!ctx->sgl.sgt.sgl)
+                               goto unlock_free;
                }
-               sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents);
+               sg_init_table(ctx->sgl.sgl, npages);
 
                ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter);
 
-               ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl, NULL, len);
+               err = extract_iter_to_sg(&msg->msg_iter, LONG_MAX,
+                                        &ctx->sgl.sgt, npages, 0);
+               if (err < 0)
+                       goto unlock_free;
+               len = err;
+               sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents - 1);
 
-               err = crypto_wait_req(crypto_ahash_update(&ctx->req),
-                                     &ctx->wait);
-               af_alg_free_sg(&ctx->sgl);
-               if (err) {
-                       iov_iter_revert(&msg->msg_iter, len);
-                       goto unlock;
+               if (!msg_data_left(msg)) {
+                       err = hash_alloc_result(sk, ctx);
+                       if (err)
+                               goto unlock_free;
                }
 
-               copied += len;
-       }
+               ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl,
+                                       ctx->result, len);
 
-       err = 0;
+               if (!msg_data_left(msg) && !continuing &&
+                   !(msg->msg_flags & MSG_MORE)) {
+                       err = crypto_ahash_digest(&ctx->req);
+               } else {
+                       if (need_init) {
+                               err = crypto_wait_req(
+                                       crypto_ahash_init(&ctx->req),
+                                       &ctx->wait);
+                               if (err)
+                                       goto unlock_free;
+                               need_init = false;
+                       }
+
+                       if (msg_data_left(msg) || (msg->msg_flags & MSG_MORE))
+                               err = crypto_ahash_update(&ctx->req);
+                       else
+                               err = crypto_ahash_finup(&ctx->req);
+                       continuing = true;
+               }
 
-       ctx->more = msg->msg_flags & MSG_MORE;
-       if (!ctx->more) {
-               err = hash_alloc_result(sk, ctx);
+               err = crypto_wait_req(err, &ctx->wait);
                if (err)
-                       goto unlock;
+                       goto unlock_free;
 
-               ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
-               err = crypto_wait_req(crypto_ahash_final(&ctx->req),
-                                     &ctx->wait);
+               copied += len;
+               af_alg_free_sg(&ctx->sgl);
        }
 
+       ctx->more = msg->msg_flags & MSG_MORE;
+       err = 0;
 unlock:
        release_sock(sk);
+       return copied ?: err;
 
-       return err ?: copied;
+unlock_free:
+       af_alg_free_sg(&ctx->sgl);
+       goto unlock;
 }
 
 static ssize_t hash_sendpage(struct socket *sock, struct page *page,