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authorArseny Krasnov <arseny.krasnov@kaspersky.com>2021-06-11 14:12:38 +0300
committerDavid S. Miller <davem@davemloft.net>2021-06-11 13:32:47 -0700
commit44931195a5412a97c46d299227fbabad4e09010d (patch)
tree921d8fb048422460188e43819bc50909931462b5 /net/vmw_vsock
parentf07b2a5b04d4a50d931a0afe4e3e114ce09a2e4b (diff)
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virtio/vsock: dequeue callback for SOCK_SEQPACKET
Callback fetches RW packets from rx queue of socket until whole record is copied(if user's buffer is full, user is not woken up). This is done to not stall sender, because if we wake up user and it leaves syscall, nobody will send credit update for rest of record, and sender will wait for next enter of read syscall at receiver's side. So if user buffer is full, we just send credit update and drop data. Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/vmw_vsock')
-rw-r--r--net/vmw_vsock/virtio_transport_common.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index ad0d34d41444..1e1df19ec164 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -393,6 +393,78 @@ out:
return err;
}
+static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
+ struct msghdr *msg,
+ int flags)
+{
+ struct virtio_vsock_sock *vvs = vsk->trans;
+ struct virtio_vsock_pkt *pkt;
+ int dequeued_len = 0;
+ size_t user_buf_len = msg_data_left(msg);
+ bool copy_failed = false;
+ bool msg_ready = false;
+
+ spin_lock_bh(&vvs->rx_lock);
+
+ if (vvs->msg_count == 0) {
+ spin_unlock_bh(&vvs->rx_lock);
+ return 0;
+ }
+
+ while (!msg_ready) {
+ pkt = list_first_entry(&vvs->rx_queue, struct virtio_vsock_pkt, list);
+
+ if (!copy_failed) {
+ size_t pkt_len;
+ size_t bytes_to_copy;
+
+ pkt_len = (size_t)le32_to_cpu(pkt->hdr.len);
+ bytes_to_copy = min(user_buf_len, pkt_len);
+
+ if (bytes_to_copy) {
+ int err;
+
+ /* sk_lock is held by caller so no one else can dequeue.
+ * Unlock rx_lock since memcpy_to_msg() may sleep.
+ */
+ spin_unlock_bh(&vvs->rx_lock);
+
+ err = memcpy_to_msg(msg, pkt->buf, bytes_to_copy);
+ if (err) {
+ /* Copy of message failed, set flag to skip
+ * copy path for rest of fragments. Rest of
+ * fragments will be freed without copy.
+ */
+ copy_failed = true;
+ dequeued_len = err;
+ } else {
+ user_buf_len -= bytes_to_copy;
+ }
+
+ spin_lock_bh(&vvs->rx_lock);
+ }
+
+ if (dequeued_len >= 0)
+ dequeued_len += pkt_len;
+ }
+
+ if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) {
+ msg_ready = true;
+ vvs->msg_count--;
+ }
+
+ virtio_transport_dec_rx_pkt(vvs, pkt);
+ list_del(&pkt->list);
+ virtio_transport_free_pkt(pkt);
+ }
+
+ spin_unlock_bh(&vvs->rx_lock);
+
+ virtio_transport_send_credit_update(vsk);
+
+ return dequeued_len;
+}
+
ssize_t
virtio_transport_stream_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
@@ -405,6 +477,18 @@ virtio_transport_stream_dequeue(struct vsock_sock *vsk,
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
+ssize_t
+virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
+ struct msghdr *msg,
+ int flags)
+{
+ if (flags & MSG_PEEK)
+ return -EOPNOTSUPP;
+
+ return virtio_transport_seqpacket_do_dequeue(vsk, msg, flags);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
+
int
virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,