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.gl29...@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: c46234ebb4d1 ("tls: RX path for ktls") Signed-off-by: Doron Roberts-Kedes <doro...@fb.com> --- net/tls/tls_sw.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 1f3d9789af30..da584dc7d633 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -377,6 +377,7 @@ 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; @@ -425,8 +426,7 @@ 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, @@ -764,6 +764,7 @@ 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; @@ -807,7 +808,7 @@ 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; -- 2.17.1
