Re: [RFC PATCH net-next v6 01/14] af_vsock: generalize vsock_dgram_recvmsg() to all transports

From: Amery Hung
Date: Mon Jul 15 2024 - 19:40:30 EST

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Next in thread: Amery Hung: "[RFC PATCH net-next v6 04/14] af_vsock: generalize bind table functions"
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On Mon, Jul 15, 2024 at 1:02 AM Luigi Leonardi
<luigi.leonardi@xxxxxxxxxxx> wrote:
>
> Hi Amery, Bobby
>
> > From: Bobby Eshleman <bobby.eshleman@xxxxxxxxxxxxx>
> >
> > This commit drops the transport->dgram_dequeue callback and makes
> > vsock_dgram_recvmsg() generic to all transports.
> >
> > To make this possible, two transport-level changes are introduced:
> > - transport in the receiving path now stores the cid and port into
> > the control buffer of an skb when populating an skb. The information
> > later is used to initialize sockaddr_vm structure in recvmsg()
> > without referencing vsk->transport.
> > - transport implementations set the skb->data pointer to the beginning
> > of the payload prior to adding the skb to the socket's receive queue.
> > That is, they must use skb_pull() before enqueuing. This is an
> > agreement between the transport and the socket layer that skb->data
> > always points to the beginning of the payload (and not, for example,
> > the packet header).
> >
> Like in the other patch, please use imperative in the commit message.
> >
> > Signed-off-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxxxxxx>
> > Signed-off-by: Amery Hung <amery.hung@xxxxxxxxxxxxx>
> > ---
> > drivers/vhost/vsock.c | 1 -
> > include/linux/virtio_vsock.h | 5 ---
> > include/net/af_vsock.h | 11 ++++-
> > net/vmw_vsock/af_vsock.c | 42 +++++++++++++++++-
> > net/vmw_vsock/hyperv_transport.c | 7 ---
> > net/vmw_vsock/virtio_transport.c | 1 -
> > net/vmw_vsock/virtio_transport_common.c | 9 ----
> > net/vmw_vsock/vmci_transport.c | 59 +++----------------------
> > net/vmw_vsock/vsock_loopback.c | 1 -
> > 9 files changed, 55 insertions(+), 81 deletions(-)
> >
> > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> > index ec20ecff85c7..97fffa914e66 100644
> > --- a/drivers/vhost/vsock.c
> > +++ b/drivers/vhost/vsock.c
> > @@ -419,7 +419,6 @@ static struct virtio_transport vhost_transport = {
> > .cancel_pkt = vhost_transport_cancel_pkt,
> >
> > .dgram_enqueue = virtio_transport_dgram_enqueue,
> > - .dgram_dequeue = virtio_transport_dgram_dequeue,
> > .dgram_bind = virtio_transport_dgram_bind,
> > .dgram_allow = virtio_transport_dgram_allow,
> >
> > diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> > index c82089dee0c8..8b56b8a19ddd 100644
> > --- a/include/linux/virtio_vsock.h
> > +++ b/include/linux/virtio_vsock.h
> > @@ -177,11 +177,6 @@ virtio_transport_stream_dequeue(struct vsock_sock *vsk,
> > size_t len,
> > int type);
> > int
> > -virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> > - struct msghdr *msg,
> > - size_t len, int flags);
> > -
> > -int
> > virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
> > struct msghdr *msg,
> > size_t len);
> > diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
> > index 535701efc1e5..7aa1f5f2b1a5 100644
> > --- a/include/net/af_vsock.h
> > +++ b/include/net/af_vsock.h
> > @@ -120,8 +120,6 @@ struct vsock_transport {
> >
> > /* DGRAM. */
> > int (*dgram_bind)(struct vsock_sock *, struct sockaddr_vm *);
> > - int (*dgram_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
> > - size_t len, int flags);
> > int (*dgram_enqueue)(struct vsock_sock *, struct sockaddr_vm *,
> > struct msghdr *, size_t len);
> > bool (*dgram_allow)(u32 cid, u32 port);
> > @@ -219,6 +217,15 @@ void vsock_for_each_connected_socket(struct vsock_transport *transport,
> > int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk);
> > bool vsock_find_cid(unsigned int cid);
> >
> > +struct vsock_skb_cb {
> > + unsigned int src_cid;
> > + unsigned int src_port;
> > +};
> > +
> > +static inline struct vsock_skb_cb *vsock_skb_cb(struct sk_buff *skb) {
> > + return (struct vsock_skb_cb *)skb->cb;
> > +};
> > +
> >
>
> Running scripts/checkpatch.pl --strict --codespell on the patch shows this error:
>
> ERROR: open brace '{' following function definitions go on the next line
> #183: FILE: include/net/af_vsock.h:225:
> +static inline struct vsock_skb_cb *vsock_skb_cb(struct sk_buff *skb) {
>
> total: 1 errors, 0 warnings, 0 checks, 235 lines checked
> >
> > /**** TAP ****/
> >
> > struct vsock_tap {
> > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> > index 4b040285aa78..5e7d4d99ea2c 100644
> > --- a/net/vmw_vsock/af_vsock.c
> > +++ b/net/vmw_vsock/af_vsock.c
> > @@ -1273,11 +1273,15 @@ static int vsock_dgram_connect(struct socket *sock,
> > int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
> > size_t len, int flags)
> > {
> > + struct vsock_skb_cb *vsock_cb;
> > #ifdef CONFIG_BPF_SYSCALL
> > const struct proto *prot;
> > #endif
> > struct vsock_sock *vsk;
> > + struct sk_buff *skb;
> > + size_t payload_len;
> > struct sock *sk;
> > + int err;
> >
> > sk = sock->sk;
> > vsk = vsock_sk(sk);
> > @@ -1288,7 +1292,43 @@ int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
> > return prot->recvmsg(sk, msg, len, flags, NULL);
> > #endif
> >
> > - return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
> > + if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
> > + return -EOPNOTSUPP;
> > +
> > + if (unlikely(flags & MSG_ERRQUEUE))
> > + return sock_recv_errqueue(sk, msg, len, SOL_VSOCK, 0);
> >
> This if statement is always false!
> >
> > +
> > + /* Retrieve the head sk_buff from the socket's receive queue. */
> > + err = 0;
> > + skb = skb_recv_datagram(sk_vsock(vsk), flags, &err);
> > + if (!skb)
> > + return err;
> > +
> > + payload_len = skb->len;
> > +
> nit: I'd remove this blank line.
> > + if (payload_len > len) {
> > + payload_len = len;
> > + msg->msg_flags |= MSG_TRUNC;
> > + }
> > +
> > + /* Place the datagram payload in the user's iovec. */
> > + err = skb_copy_datagram_msg(skb, 0, msg, payload_len);
> > + if (err)
> > + goto out;
> > +
> > + if (msg->msg_name) {
> > + /* Provide the address of the sender. */
> > + DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
> > +
> > + vsock_cb = vsock_skb_cb(skb);
> > + vsock_addr_init(vm_addr, vsock_cb->src_cid, vsock_cb->src_port);
> > + msg->msg_namelen = sizeof(*vm_addr);
> > + }
> > + err = payload_len;
> > +
> > +out:
> > + skb_free_datagram(&vsk->sk, skb);
> > + return err;
> > }
> > EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
> >
> > diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
> > index e2157e387217..326dd41ee2d5 100644
> > --- a/net/vmw_vsock/hyperv_transport.c
> > +++ b/net/vmw_vsock/hyperv_transport.c
> > @@ -556,12 +556,6 @@ static int hvs_dgram_bind(struct vsock_sock *vsk, struct sockaddr_vm *addr)
> > return -EOPNOTSUPP;
> > }
> >
> > -static int hvs_dgram_dequeue(struct vsock_sock *vsk, struct msghdr *msg,
> > - size_t len, int flags)
> > -{
> > - return -EOPNOTSUPP;
> > -}
> > -
> > static int hvs_dgram_enqueue(struct vsock_sock *vsk,
> > struct sockaddr_vm *remote, struct msghdr *msg,
> > size_t dgram_len)
> > @@ -833,7 +827,6 @@ static struct vsock_transport hvs_transport = {
> > .shutdown = hvs_shutdown,
> >
> > .dgram_bind = hvs_dgram_bind,
> > - .dgram_dequeue = hvs_dgram_dequeue,
> > .dgram_enqueue = hvs_dgram_enqueue,
> > .dgram_allow = hvs_dgram_allow,
> >
> > diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> > index 43d405298857..a8c97e95622a 100644
> > --- a/net/vmw_vsock/virtio_transport.c
> > +++ b/net/vmw_vsock/virtio_transport.c
> > @@ -508,7 +508,6 @@ static struct virtio_transport virtio_transport = {
> > .cancel_pkt = virtio_transport_cancel_pkt,
> >
> > .dgram_bind = virtio_transport_dgram_bind,
> > - .dgram_dequeue = virtio_transport_dgram_dequeue,
> > .dgram_enqueue = virtio_transport_dgram_enqueue,
> > .dgram_allow = virtio_transport_dgram_allow,
> >
> > diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> > index 16ff976a86e3..4bf73d20c12a 100644
> > --- a/net/vmw_vsock/virtio_transport_common.c
> > +++ b/net/vmw_vsock/virtio_transport_common.c
> > @@ -810,15 +810,6 @@ virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
> > }
> > EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
> >
> > -int
> > -virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> > - struct msghdr *msg,
> > - size_t len, int flags)
> > -{
> > - return -EOPNOTSUPP;
> > -}
> > -EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
> > -
> > s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
> > {
> > struct virtio_vsock_sock *vvs = vsk->trans;
> > diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
> > index b370070194fa..b39df3ed8c8d 100644
> > --- a/net/vmw_vsock/vmci_transport.c
> > +++ b/net/vmw_vsock/vmci_transport.c
> > @@ -610,6 +610,7 @@ vmci_transport_datagram_create_hnd(u32 resource_id,
> >
> > static int vmci_transport_recv_dgram_cb(void *data, struct vmci_datagram *dg)
> > {
> > + struct vsock_skb_cb *vsock_cb;
> > struct sock *sk;
> > size_t size;
> > struct sk_buff *skb;
> > @@ -637,10 +638,14 @@ static int vmci_transport_recv_dgram_cb(void *data, struct vmci_datagram *dg)
> > if (!skb)
> > return VMCI_ERROR_NO_MEM;
> >
> > + vsock_cb = vsock_skb_cb(skb);
> > + vsock_cb->src_cid = dg->src.context;
> > + vsock_cb->src_port = dg->src.resource;
> > /* sk_receive_skb() will do a sock_put(), so hold here. */
> > sock_hold(sk);
> > skb_put(skb, size);
> > memcpy(skb->data, dg, size);
> > + skb_pull(skb, VMCI_DG_HEADERSIZE);
> > sk_receive_skb(sk, skb, 0);
> >
> > return VMCI_SUCCESS;
> > @@ -1731,59 +1736,6 @@ static int vmci_transport_dgram_enqueue(
> > return err - sizeof(*dg);
> > }
> >
> > -static int vmci_transport_dgram_dequeue(struct vsock_sock *vsk,
> > - struct msghdr *msg, size_t len,
> > - int flags)
> > -{
> > - int err;
> > - struct vmci_datagram *dg;
> > - size_t payload_len;
> > - struct sk_buff *skb;
> > -
> > - if (flags & MSG_OOB || flags & MSG_ERRQUEUE)
> > - return -EOPNOTSUPP;
> > -
> > - /* Retrieve the head sk_buff from the socket's receive queue. */
> > - err = 0;
> > - skb = skb_recv_datagram(&vsk->sk, flags, &err);
> > - if (!skb)
> > - return err;
> > -
> > - dg = (struct vmci_datagram *)skb->data;
> > - if (!dg)
> > - /* err is 0, meaning we read zero bytes. */
> > - goto out;
> > -
> > - payload_len = dg->payload_size;
> > - /* Ensure the sk_buff matches the payload size claimed in the packet. */
> > - if (payload_len != skb->len - sizeof(*dg)) {
> > - err = -EINVAL;
> > - goto out;
> > - }
> > -
> > - if (payload_len > len) {
> > - payload_len = len;
> > - msg->msg_flags |= MSG_TRUNC;
> > - }
> > -
> > - /* Place the datagram payload in the user's iovec. */
> > - err = skb_copy_datagram_msg(skb, sizeof(*dg), msg, payload_len);
> > - if (err)
> > - goto out;
> > -
> > - if (msg->msg_name) {
> > - /* Provide the address of the sender. */
> > - DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
> > - vsock_addr_init(vm_addr, dg->src.context, dg->src.resource);
> > - msg->msg_namelen = sizeof(*vm_addr);
> > - }
> > - err = payload_len;
> > -
> > -out:
> > - skb_free_datagram(&vsk->sk, skb);
> > - return err;
> > -}
> > -
> > static bool vmci_transport_dgram_allow(u32 cid, u32 port)
> > {
> > if (cid == VMADDR_CID_HYPERVISOR) {
> > @@ -2040,7 +1992,6 @@ static struct vsock_transport vmci_transport = {
> > .release = vmci_transport_release,
> > .connect = vmci_transport_connect,
> > .dgram_bind = vmci_transport_dgram_bind,
> > - .dgram_dequeue = vmci_transport_dgram_dequeue,
> > .dgram_enqueue = vmci_transport_dgram_enqueue,
> > .dgram_allow = vmci_transport_dgram_allow,
> > .stream_dequeue = vmci_transport_stream_dequeue,
> > diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
> > index 6dea6119f5b2..11488887a5cc 100644
> > --- a/net/vmw_vsock/vsock_loopback.c
> > +++ b/net/vmw_vsock/vsock_loopback.c
> > @@ -66,7 +66,6 @@ static struct virtio_transport loopback_transport = {
> > .cancel_pkt = vsock_loopback_cancel_pkt,
> >
> > .dgram_bind = virtio_transport_dgram_bind,
> > - .dgram_dequeue = virtio_transport_dgram_dequeue,
> > .dgram_enqueue = virtio_transport_dgram_enqueue,
> > .dgram_allow = virtio_transport_dgram_allow,
> >
> > --
> > 2.20.1
> >
> >
>
> Small changes :)
> Rest LGTM!
>

I will fix the two style issues.

Thank you,
Amery

> Thanks,
> Luigi

Next message: Ingo Molnar: "[GIT PULL] objtool changes for v6.11"
Previous message: Alistair Francis: "Re: [PATCH v14 3/4] PCI/DOE: Expose the DOE features via sysfs"
In reply to: Luigi Leonardi: "Re: [RFC PATCH net-next v6 01/14] af_vsock: generalize vsock_dgram_recvmsg() to all transports"
Next in thread: Amery Hung: "[RFC PATCH net-next v6 04/14] af_vsock: generalize bind table functions"
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