[PATCH RFC 0/4] Add support for async socket operations

[PATCH RFC 0/4] Add support for async socket operations

[Tadeusz Struk]

After the iocb parameter has been removed from sendmsg() and recvmsg() ops
the socket layer, and the network stack no longer support async operations.
This patch set adds support for asynchronous operations on sockets back.

--
Tadeusz Struk (4):
      net: socket: add support for async operations
      aio: prefer aio_op op over inter_op
      crypto: af_alg - Allow to link sgl
      crypto: algif - change algif_skcipher to be asynchronous


 crypto/af_alg.c         |   18 +++-
 crypto/algif_skcipher.c |  224 ++++++++++++++++++++++++++++++++++++++++++++++-
 fs/aio.c                |    8 +-
 include/crypto/if_alg.h |    4 +
 include/linux/net.h     |    8 ++
 net/socket.c            |   64 +++++++++++++
 6 files changed, 312 insertions(+), 14 deletions(-)

-- 

[PATCH RFC 1/4] net: socket: add support for async operations

[Tadeusz Struk]

Add support for async operations.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
---
 include/linux/net.h |    6 +++++
 net/socket.c        |   64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/include/linux/net.h b/include/linux/net.h
index e74114b..8330936 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -25,6 +25,7 @@
 #include <linux/kmemcheck.h>
 #include <linux/rcupdate.h>
 #include <linux/jump_label.h>
+#include <linux/aio.h>
 #include <uapi/linux/net.h>
 
 struct poll_table_struct;
@@ -173,6 +174,11 @@ struct proto_ops {
 	 */
 	int		(*recvmsg)   (struct socket *sock, struct msghdr *m,
 				      size_t total_len, int flags);
+	int		(*aio_sendmsg)(struct kiocb *iocb, struct socket *sock,
+				       struct msghdr *m, size_t total_len);
+	int		(*aio_recvmsg)(struct kiocb *iocb, struct socket *sock,
+				       struct msghdr *m, size_t total_len,
+				       int flags);
 	int		(*mmap)	     (struct file *file, struct socket *sock,
 				      struct vm_area_struct * vma);
 	ssize_t		(*sendpage)  (struct socket *sock, struct page *page,
diff --git a/net/socket.c b/net/socket.c
index 95d3085..fe55112 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -132,6 +132,11 @@ static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
 				struct pipe_inode_info *pipe, size_t len,
 				unsigned int flags);
 
+static ssize_t sock_aio_read(struct kiocb *iocb, const struct iovec *iov,
+			     unsigned long nr_segs, loff_t loff);
+static ssize_t sock_aio_write(struct kiocb *iocb, const struct iovec *iov,
+			      unsigned long nr_segs, loff_t loff);
+
 /*
  *	Socket files have a set of 'special' operations as well as the generic file ones. These don't appear
  *	in the operation structures but are done directly via the socketcall() multiplexor.
@@ -144,6 +149,8 @@ static const struct file_operations socket_file_ops = {
 	.write =	new_sync_write,
 	.read_iter =	sock_read_iter,
 	.write_iter =	sock_write_iter,
+	.aio_read =	sock_aio_read,
+	.aio_write =	sock_aio_write,
 	.poll =		sock_poll,
 	.unlocked_ioctl = sock_ioctl,
 #ifdef CONFIG_COMPAT
@@ -836,6 +843,63 @@ static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	return res;
 }
 
+static ssize_t sock_aio_read(struct kiocb *iocb, const struct iovec *iov,
+			     unsigned long nr_segs, loff_t loff)
+{
+	struct file *file = iocb->ki_filp;
+	struct socket *sock = file->private_data;
+	struct iov_iter iter;
+	struct msghdr msg = {0};
+	ssize_t res;
+
+	if (file->f_flags & O_NONBLOCK)
+		msg.msg_flags = MSG_DONTWAIT;
+
+	if (iocb->ki_pos != 0)
+		return -ESPIPE;
+
+	if (iocb->ki_nbytes == 0)
+		return 0;
+
+	if (sock->ops->aio_recvmsg) {
+		iov_iter_init(&iter, READ, iov, nr_segs, iocb->ki_nbytes);
+		msg.msg_iter = iter;
+		res = sock->ops->aio_recvmsg(iocb, sock, &msg,
+					     iocb->ki_nbytes, msg.msg_flags);
+	} else {
+		res = -EOPNOTSUPP;
+	}
+	return res;
+}
+
+static ssize_t sock_aio_write(struct kiocb *iocb, const struct iovec *iov,
+			      unsigned long nr_segs, loff_t loff)
+{
+	struct file *file = iocb->ki_filp;
+	struct socket *sock = file->private_data;
+	struct iov_iter iter;
+	struct msghdr msg = {0};
+	ssize_t res;
+
+	if (iocb->ki_pos != 0)
+		return -ESPIPE;
+
+	if (file->f_flags & O_NONBLOCK)
+		msg.msg_flags = MSG_DONTWAIT;
+
+	if (sock->type == SOCK_SEQPACKET)
+		msg.msg_flags |= MSG_EOR;
+
+	if (sock->ops->aio_sendmsg) {
+		iov_iter_init(&iter, WRITE, iov, nr_segs, iocb->ki_nbytes);
+		msg.msg_iter = iter;
+		res = sock->ops->aio_sendmsg(iocb, sock, &msg, iocb->ki_nbytes);
+	} else {
+		res = -EOPNOTSUPP;
+	}
+	return res;
+}
+
 /*
  * Atomic setting of ioctl hooks to avoid race
  * with module unload.

[PATCH RFC 2/4] aio: prefer aio_op op over iter_op

[Tadeusz Struk]

AIO interface should prefer AIO operations over iter_op

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
---
 fs/aio.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index f8e52a1..389f4dd 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1449,11 +1449,15 @@ rw_common:
 		if (rw == WRITE)
 			file_start_write(file);
 
-		if (iter_op) {
+		if (rw_op) {
+			ret = rw_op(req, iovec, nr_segs, req->ki_pos);
+		} else if (iter_op) {
 			iov_iter_init(&iter, rw, iovec, nr_segs, req->ki_nbytes);
 			ret = iter_op(req, &iter);
 		} else {
-			ret = rw_op(req, iovec, nr_segs, req->ki_pos);
+			if (iovec != inline_vecs)
+				kfree(iovec);
+			return -EINVAL;
 		}
 
 		if (rw == WRITE)

Re: [PATCH RFC 2/4] aio: prefer aio_op op over iter_op

[Al Viro]

On Wed, Mar 11, 2015 at 03:46:18PM -0700, Tadeusz Struk wrote:
> AIO interface should prefer AIO operations over iter_op

What the devil for?  read_iter and write_iter *ARE* aio operations, as much
as soon to be removed aio_read and aio_write.  And yes, those are going to
be removed very soon.

Note that ->read_iter() and ->write_iter() are getting iocb pointer passed
to them.  It's just that socket instances are not passing it along to
->sendmsg/->recvmsg anymore.

And why, in name of everything unholy, do your methods get redundant
total_len argument?  It's iov_iter_count(&msg->msg_iter) (and in iov_iter-net
I have an inline helper doing that - enough places open-coding that thing).
If nothing else, ->sendmsg() and ->recvmsg() would benefit from removing
that argument as well.  I have patches doing that, but iocb removal conflicts
with them and they need to be rebased to current net/master...

Re: [PATCH RFC 2/4] aio: prefer aio_op op over iter_op

[Tadeusz Struk]

On 03/11/2015 11:48 PM, Al Viro wrote:
>> AIO interface should prefer AIO operations over iter_op
> What the devil for?  read_iter and write_iter *ARE* aio operations, as much
> as soon to be removed aio_read and aio_write.  And yes, those are going to
> be removed very soon.

That's fine. When those will get removed, then as part of the cleanup we can 
merge sock_read_iter() with sock_aio_read() and sock_write_iter()
with sock_aio_write() and call sock_recvmsg()/sock_sendmsg() or 
sock->ops->aio_recvmsg()/sock->ops->aio_sendmsg based on if (is_sync_kiocb(iocb))

> 
> Note that ->read_iter() and ->write_iter() are getting iocb pointer passed
> to them.  It's just that socket instances are not passing it along to
> ->sendmsg/->recvmsg anymore.

and that's the main reason why I have added the sock_aio_read() and sock_aio_write()
I didn't want to mess with the sock_read_iter() and sock_write_iter() for now.

> 
> And why, in name of everything unholy, do your methods get redundant
> total_len argument?  It's iov_iter_count(&msg->msg_iter) (and in iov_iter-net
> I have an inline helper doing that - enough places open-coding that thing).
> If nothing else, ->sendmsg() and ->recvmsg() would benefit from removing
> that argument as well.  I have patches doing that, but iocb removal conflicts
> with them and they need to be rebased to current net/master...

You are right, it's not needed at all. I took the signatures from sendmsg() and
recvmsg() and just added iocb. I will remove them in v2 if you want, or you can
add it to your patches.

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[PATCH RFC 3/4] crypto: af_alg - Allow to link sgl

[Tadeusz Struk]

From: Tadeusz Struk <tadeusz.struk@intel.com>

Allow to link af_alg sgls.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
---
 crypto/af_alg.c         |   18 +++++++++++++-----
 include/crypto/if_alg.h |    4 +++-
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 7f8b7edc..26089d1 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 178525e..018afb2 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);
 

[PATCH RFC 4/4] crypto: algif - change algif_skcipher to be asynchronous

[Tadeusz Struk]

From: Tadeusz Struk <tadeusz.struk@intel.com>

The way the algif_skcipher works currently is that on sendmsg/sendpage it
builds an sgl for the input data and then on read/recvmsg it sends the job
for encryption putting the user to sleep till the data is processed.
This way it can only handle one job at a given time.
This patch changes it to be asynchronous by adding AIO support.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
---
 crypto/algif_skcipher.c |  224 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 218 insertions(+), 6 deletions(-)

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index b9743dc..b259cbd 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -39,6 +39,7 @@ struct skcipher_ctx {
 
 	struct af_alg_completion completion;
 
+	atomic_t inflight;
 	unsigned used;
 
 	unsigned int len;
@@ -49,9 +50,65 @@ struct skcipher_ctx {
 	struct ablkcipher_request req;
 };
 
+struct skcipher_async_rsgl {
+	struct af_alg_sgl sgl;
+	struct list_head list;
+};
+
+struct skcipher_async_req {
+	struct kiocb *iocb;
+	struct skcipher_async_rsgl first_sgl;
+	struct list_head list;
+	struct scatterlist *tsg;
+	char iv[];
+};
+
+#define GET_SREQ(areq, ctx) (struct skcipher_async_req *)((char *)areq + \
+	crypto_ablkcipher_reqsize(crypto_ablkcipher_reqtfm(&ctx->req)))
+
+#define GET_REQ_SIZE(ctx) \
+	crypto_ablkcipher_reqsize(crypto_ablkcipher_reqtfm(&ctx->req))
+
+#define GET_IV_SIZE(ctx) \
+	crypto_ablkcipher_ivsize(crypto_ablkcipher_reqtfm(&ctx->req))
+
 #define MAX_SGL_ENTS ((4096 - sizeof(struct skcipher_sg_list)) / \
 		      sizeof(struct scatterlist) - 1)
 
+static void skcipher_free_async_sgls(struct skcipher_async_req *sreq)
+{
+	struct skcipher_async_rsgl *rsgl, *tmp;
+	struct scatterlist *sgl;
+	struct scatterlist *sg;
+	int i, n;
+
+	list_for_each_entry_safe(rsgl, tmp, &sreq->list, list) {
+		af_alg_free_sg(&rsgl->sgl);
+		if (rsgl != &sreq->first_sgl)
+			kfree(rsgl);
+	}
+	sgl = sreq->tsg;
+	n = sg_nents(sgl);
+	for_each_sg(sgl, sg, n, i)
+		put_page(sg_page(sg));
+
+	kfree(sreq->tsg);
+}
+
+static void skcipher_async_cb(struct crypto_async_request *req, int err)
+{
+	struct sock *sk = req->data;
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct skcipher_async_req *sreq = GET_SREQ(req, ctx);
+	struct kiocb *iocb = sreq->iocb;
+
+	atomic_dec(&ctx->inflight);
+	skcipher_free_async_sgls(sreq);
+	kfree(req);
+	aio_complete(iocb, err, err);
+}
+
 static inline int skcipher_sndbuf(struct sock *sk)
 {
 	struct alg_sock *ask = alg_sk(sk);
@@ -96,7 +153,7 @@ static int skcipher_alloc_sgl(struct sock *sk)
 	return 0;
 }
 
-static void skcipher_pull_sgl(struct sock *sk, int used)
+static void skcipher_pull_sgl(struct sock *sk, int used, int put)
 {
 	struct alg_sock *ask = alg_sk(sk);
 	struct skcipher_ctx *ctx = ask->private;
@@ -123,8 +180,8 @@ static void skcipher_pull_sgl(struct sock *sk, int used)
 
 			if (sg[i].length)
 				return;
-
-			put_page(sg_page(sg + i));
+			if (put)
+				put_page(sg_page(sg + i));
 			sg_assign_page(sg + i, NULL);
 		}
 
@@ -143,7 +200,7 @@ static void skcipher_free_sgl(struct sock *sk)
 	struct alg_sock *ask = alg_sk(sk);
 	struct skcipher_ctx *ctx = ask->private;
 
-	skcipher_pull_sgl(sk, ctx->used);
+	skcipher_pull_sgl(sk, ctx->used, 1);
 }
 
 static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags)
@@ -424,6 +481,147 @@ unlock:
 	return err ?: size;
 }
 
+static int skcipher_all_sg_nents(struct skcipher_ctx *ctx)
+{
+	struct skcipher_sg_list *sgl;
+	struct scatterlist *sg;
+	int nents = 0;
+
+	list_for_each_entry(sgl, &ctx->tsgl, list) {
+		sg = sgl->sg;
+
+		while (!sg->length)
+			sg++;
+
+		nents += sg_nents(sg);
+	}
+	return nents;
+}
+
+static int skcipher_recvmsg_async(struct kiocb *iocb, struct socket *sock,
+				  struct msghdr *msg, size_t ignored, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct skcipher_sg_list *sgl;
+	struct scatterlist *sg;
+	struct skcipher_async_req *sreq;
+	struct ablkcipher_request *req;
+	struct skcipher_async_rsgl *last_rsgl = NULL;
+	unsigned int len = 0, tx_nents = skcipher_all_sg_nents(ctx);
+	unsigned int reqlen = sizeof(struct skcipher_async_req) +
+				GET_REQ_SIZE(ctx) + GET_IV_SIZE(ctx);
+	int i = 0;
+	int err = -ENOMEM;
+
+	lock_sock(sk);
+	req = kmalloc(reqlen, GFP_KERNEL);
+	if (unlikely(!req))
+		goto unlock;
+
+	sreq = GET_SREQ(req, ctx);
+	sreq->iocb = iocb;
+	memset(&sreq->first_sgl, '\0', sizeof(struct skcipher_async_rsgl));
+	INIT_LIST_HEAD(&sreq->list);
+	sreq->tsg = kcalloc(tx_nents, sizeof(*sg), GFP_KERNEL);
+	if (unlikely(!sreq->tsg)) {
+		kfree(req);
+		goto unlock;
+	}
+	sg_init_table(sreq->tsg, tx_nents);
+	memcpy(sreq->iv, ctx->iv, GET_IV_SIZE(ctx));
+	ablkcipher_request_set_tfm(req, crypto_ablkcipher_reqtfm(&ctx->req));
+	ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+					skcipher_async_cb, sk);
+
+	while (iov_iter_count(&msg->msg_iter)) {
+		struct skcipher_async_rsgl *rsgl;
+		unsigned long used;
+
+		if (!ctx->used) {
+			err = skcipher_wait_for_data(sk, flags);
+			if (err)
+				goto free;
+		}
+		sgl = list_first_entry(&ctx->tsgl,
+				       struct skcipher_sg_list, list);
+		sg = sgl->sg;
+
+		while (!sg->length)
+			sg++;
+
+		used = min_t(unsigned long, ctx->used,
+			     iov_iter_count(&msg->msg_iter));
+		used = min_t(unsigned long, used, sg->length);
+
+		if (i == tx_nents) {
+			struct scatterlist *tmp;
+			int x;
+			/* Ran out of tx slots in async request
+			 * need to expand */
+			tmp = kcalloc(tx_nents * 2, sizeof(*tmp),
+				      GFP_KERNEL);
+			if (!tmp)
+				goto free;
+
+			sg_init_table(tmp, tx_nents * 2);
+			for (x = 0; x < tx_nents; x++)
+				sg_set_page(&tmp[x], sg_page(&sreq->tsg[x]),
+					    sreq->tsg[x].length,
+					    sreq->tsg[x].offset);
+			kfree(sreq->tsg);
+			sreq->tsg = tmp;
+			tx_nents *= 2;
+		}
+		/* Need to take over the tx sgl from ctx
+		 * to the asynch req - these sgls will be freed later */
+		sg_set_page(sreq->tsg + i++, sg_page(sg), sg->length,
+			    sg->offset);
+
+		if (list_empty(&sreq->list)) {
+			rsgl = &sreq->first_sgl;
+			list_add_tail(&rsgl->list, &sreq->list);
+		} else {
+			rsgl = kzalloc(sizeof(*rsgl), GFP_KERNEL);
+			if (!rsgl) {
+				err = -ENOMEM;
+				goto free;
+			}
+			list_add_tail(&rsgl->list, &sreq->list);
+		}
+
+		used = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, used);
+		err = used;
+		if (used < 0)
+			goto free;
+		if (last_rsgl)
+			af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
+
+		last_rsgl = rsgl;
+		len += used;
+		skcipher_pull_sgl(sk, used, 0);
+		iov_iter_advance(&msg->msg_iter, used);
+	}
+
+	ablkcipher_request_set_crypt(req, sreq->tsg, sreq->first_sgl.sgl.sg,
+				     len, sreq->iv);
+	err = ctx->enc ? crypto_ablkcipher_encrypt(req) :
+			 crypto_ablkcipher_decrypt(req);
+	if (err == -EINPROGRESS) {
+		atomic_inc(&ctx->inflight);
+		err = -EIOCBQUEUED;
+		goto unlock;
+	}
+free:
+	skcipher_free_async_sgls(sreq);
+	kfree(req);
+unlock:
+	skcipher_wmem_wakeup(sk);
+	release_sock(sk);
+	return err;
+}
+
 static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 			    size_t ignored, int flags)
 {
@@ -484,7 +682,7 @@ free:
 			goto unlock;
 
 		copied += used;
-		skcipher_pull_sgl(sk, used);
+		skcipher_pull_sgl(sk, used, 1);
 		iov_iter_advance(&msg->msg_iter, used);
 	}
 
@@ -497,7 +695,6 @@ unlock:
 	return copied ?: err;
 }
 
-
 static unsigned int skcipher_poll(struct file *file, struct socket *sock,
 				  poll_table *wait)
 {
@@ -537,6 +734,7 @@ static struct proto_ops algif_skcipher_ops = {
 	.sendmsg	=	skcipher_sendmsg,
 	.sendpage	=	skcipher_sendpage,
 	.recvmsg	=	skcipher_recvmsg,
+	.aio_recvmsg	=	skcipher_recvmsg_async,
 	.poll		=	skcipher_poll,
 };
 
@@ -555,12 +753,25 @@ static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
 	return crypto_ablkcipher_setkey(private, key, keylen);
 }
 
+static void skcipher_wait(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	int ctr = 0;
+
+	while (atomic_read(&ctx->inflight) && ctr++ < 100)
+		msleep(100);
+}
+
 static void skcipher_sock_destruct(struct sock *sk)
 {
 	struct alg_sock *ask = alg_sk(sk);
 	struct skcipher_ctx *ctx = ask->private;
 	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
 
+	if (atomic_read(&ctx->inflight))
+		skcipher_wait(sk);
+
 	skcipher_free_sgl(sk);
 	sock_kzfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
 	sock_kfree_s(sk, ctx, ctx->len);
@@ -592,6 +803,7 @@ static int skcipher_accept_parent(void *private, struct sock *sk)
 	ctx->more = 0;
 	ctx->merge = 0;
 	ctx->enc = 0;
+	atomic_set(&ctx->inflight, 0);
 	af_alg_init_completion(&ctx->completion);
 
 	ask->private = ctx;