2 files changed, 16 insertions, 6 deletions

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 7f8b7edcadca..26089d182cb7 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -358,8 +358,8 @@ int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
         npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
         if (WARN_ON(npages == 0))
                 return -EINVAL;
-
-        sg_init_table(sgl->sg, npages);
+        /* 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);
@@ -369,18 +369,26 @@ int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
                 off = 0;
                 len -= plen;
         }
+        sg_mark_end(sgl->sg + npages - 1);
+        sgl->npages = npages;
+
         return n;
 }
 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 
+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);
+}
+EXPORT_SYMBOL(af_alg_link_sg);
+
 void af_alg_free_sg(struct af_alg_sgl *sgl)
 {
         int i;
 
-        i = 0;
-        do {
+        for (i = 0; i < sgl->npages; i++)
                 put_page(sgl->pages[i]);
-        } while (!sg_is_last(sgl->sg + (i++)));
 }
 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 178525e5f430..018afb264ac2 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -58,8 +58,9 @@ struct af_alg_type {
 };
 
 struct af_alg_sgl {
-        struct scatterlist sg[ALG_MAX_PAGES];
+        struct scatterlist sg[ALG_MAX_PAGES + 1];
         struct page *pages[ALG_MAX_PAGES];
+        unsigned int npages;
 };
 
 int af_alg_register_type(const struct af_alg_type *type);
@@ -70,6 +71,7 @@ int af_alg_accept(struct sock *sk, struct socket *newsock);
 
 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);
+void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new);
 
 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con);