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Commit 0a26cf3f authored by Doron Roberts-Kedes's avatar Doron Roberts-Kedes Committed by David S. Miller
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tls: Skip zerocopy path for ITER_KVEC 

The zerocopy path ultimately calls iov_iter_get_pages, which defines the
step function for ITER_KVECs as simply, return -EFAULT. Taking the
non-zerocopy path for ITER_KVECs avoids the unnecessary fallback.

See https://lore.kernel.org/lkml/20150401023311.GL29656@ZenIV.linux.org.uk/T/#u


for a discussion of why zerocopy for vmalloc data is not a good idea.

Discovered while testing NBD traffic encrypted with ktls.

Fixes: c46234eb ("tls: RX path for ktls")
Signed-off-by: default avatarDoron Roberts-Kedes <doronrk@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2ed9db30

net/tls/tls_sw.c

+4 −3
Original line number Diff line number Diff line
@@ -362,6 +362,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 
	int record_room;

	bool full_record;

	int orig_size;

	bool is_kvec = msg->msg_iter.type & ITER_KVEC;



	if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))

		return -ENOTSUPP;
@@ -410,8 +411,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 
			try_to_copy -= required_size - ctx->sg_encrypted_size;

			full_record = true;

		}



		if (full_record || eor) {

		if (!is_kvec && (full_record || eor)) {

			ret = zerocopy_from_iter(sk, &msg->msg_iter,

				try_to_copy, &ctx->sg_plaintext_num_elem,

				&ctx->sg_plaintext_size,
@@ -779,6 +779,7 @@ int tls_sw_recvmsg(struct sock *sk, 
	bool cmsg = false;

	int target, err = 0;

	long timeo;

	bool is_kvec = msg->msg_iter.type & ITER_KVEC;



	flags |= nonblock;
@@ -822,7 +823,7 @@ int tls_sw_recvmsg(struct sock *sk, 
			page_count = iov_iter_npages(&msg->msg_iter,

						     MAX_SKB_FRAGS);

			to_copy = rxm->full_len - tls_ctx->rx.overhead_size;

			if (to_copy <= len && page_count < MAX_SKB_FRAGS &&

			if (!is_kvec && to_copy <= len && page_count < MAX_SKB_FRAGS &&

			    likely(!(flags & MSG_PEEK)))  {

				struct scatterlist sgin[MAX_SKB_FRAGS + 1];

				int pages = 0;