Stefano Garzarella
2023-Jun-22 14:51 UTC
[PATCH RFC net-next v4 1/8] vsock/dgram: generalize recvmsg and drop transport->dgram_dequeue
On Sun, Jun 11, 2023 at 11:43:15PM +0300, Arseniy Krasnov wrote:>Hello Bobby! Thanks for this patchset! Small comment below: > >On 10.06.2023 03:58, Bobby Eshleman wrote: >> This commit drops the transport->dgram_dequeue callback and makes >> vsock_dgram_recvmsg() generic. It also adds additional transport >> callbacks for use by the generic vsock_dgram_recvmsg(), such as for >> parsing skbs for CID/port which vary in format per transport. >> >> Signed-off-by: Bobby Eshleman <bobby.eshleman at bytedance.com> >> --- >> drivers/vhost/vsock.c | 4 +- >> include/linux/virtio_vsock.h | 3 ++ >> include/net/af_vsock.h | 13 ++++++- >> net/vmw_vsock/af_vsock.c | 51 ++++++++++++++++++++++++- >> net/vmw_vsock/hyperv_transport.c | 17 +++++++-- >> net/vmw_vsock/virtio_transport.c | 4 +- >> net/vmw_vsock/virtio_transport_common.c | 18 +++++++++ >> net/vmw_vsock/vmci_transport.c | 68 +++++++++++++-------------------- >> net/vmw_vsock/vsock_loopback.c | 4 +- >> 9 files changed, 132 insertions(+), 50 deletions(-) >> >> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c >> index 6578db78f0ae..c8201c070b4b 100644 >> --- a/drivers/vhost/vsock.c >> +++ b/drivers/vhost/vsock.c >> @@ -410,9 +410,11 @@ 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, >> + .dgram_get_cid = virtio_transport_dgram_get_cid, >> + .dgram_get_port = virtio_transport_dgram_get_port, >> + .dgram_get_length = virtio_transport_dgram_get_length, >> >> .stream_enqueue = virtio_transport_stream_enqueue, >> .stream_dequeue = virtio_transport_stream_dequeue, >> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h >> index c58453699ee9..23521a318cf0 100644 >> --- a/include/linux/virtio_vsock.h >> +++ b/include/linux/virtio_vsock.h >> @@ -219,6 +219,9 @@ bool virtio_transport_stream_allow(u32 cid, u32 port); >> int virtio_transport_dgram_bind(struct vsock_sock *vsk, >> struct sockaddr_vm *addr); >> bool virtio_transport_dgram_allow(u32 cid, u32 port); >> +int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid); >> +int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port); >> +int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len); >> >> int virtio_transport_connect(struct vsock_sock *vsk); >> >> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h >> index 0e7504a42925..7bedb9ee7e3e 100644 >> --- a/include/net/af_vsock.h >> +++ b/include/net/af_vsock.h >> @@ -120,11 +120,20 @@ 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); >> + int (*dgram_get_cid)(struct sk_buff *skb, unsigned int *cid); >> + int (*dgram_get_port)(struct sk_buff *skb, unsigned int *port); >> + int (*dgram_get_length)(struct sk_buff *skb, size_t *length); >> + >> + /* The number of bytes into the buffer at which the payload starts, as >> + * first seen by the receiving socket layer. For example, if the >> + * transport presets the skb pointers using skb_pull(sizeof(header)) >> + * than this would be zero, otherwise it would be the size of the >> + * header. >> + */ >> + const size_t dgram_payload_offset; >> >> /* STREAM. */ >> /* TODO: stream_bind() */ >> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c >> index efb8a0937a13..ffb4dd8b6ea7 100644 >> --- a/net/vmw_vsock/af_vsock.c >> +++ b/net/vmw_vsock/af_vsock.c >> @@ -1271,11 +1271,15 @@ static int vsock_dgram_connect(struct socket *sock, >> int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg, >> size_t len, int flags) >> { >> + const struct vsock_transport *transport; >> #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); >> @@ -1286,7 +1290,52 @@ 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; >> + >> + transport = vsk->transport; >> + >> + /* 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; >> + >> + err = transport->dgram_get_length(skb, &payload_len);What about ssize_t return value here? Or maybe a single callback that return both length and offset? .dgram_get_payload_info(skb, &payload_len, &payload_off)>> + if (err) >> + 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, transport->dgram_payload_offset, 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); >> + unsigned int cid, port; >> + >> + err = transport->dgram_get_cid(skb, &cid); >> + if (err) >> + goto out; >> + >> + err = transport->dgram_get_port(skb, &port); >> + if (err) >> + goto out; > >Maybe we can merge 'dgram_get_cid' and 'dgram_get_port' to a single callback? Because I see that this is >the only place where both are used (correct me if i'm wrong) and logically both operates with addresses: >CID and port. E.g. something like that: dgram_get_cid_n_port().What about .dgram_addr_init(struct sk_buff *skb, struct sockaddr_vm *addr) and the transport can set cid and port?> >Moreover, I'm not sure, but is it good "tradeoff" here: remove transport specific callback for dgram receive >where we already have 'msghdr' with both data buffer and buffer for 'sockaddr_vm' and instead of it add new >several fields (callbacks) to transports like dgram_get_cid(), dgram_get_port()? I agree, that in each transport >specific callback we will have same copying logic by calling 'skb_copy_datagram_msg()' and filling address >by using 'vsock_addr_init()', but in this case we don't need to update transports too much. For example HyperV >still unchanged as it does not support SOCK_DGRAM. For VMCI You just need to add 'vsock_addr_init()' logic >to it's dgram dequeue callback. > >What do You think?Honestly, I'd rather avoid duplicate code than reduce changes in transports that don't support dgram. One thing I do agree on though is minimizing the number of callbacks to call to reduce the number of indirection (more performance?). Thanks, Stefano> >Thanks, Arseniy > >> + >> + vsock_addr_init(vm_addr, cid, 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 7cb1a9d2cdb4..ff6e87e25fa0 100644 >> --- a/net/vmw_vsock/hyperv_transport.c >> +++ b/net/vmw_vsock/hyperv_transport.c >> @@ -556,8 +556,17 @@ 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) >> +static int hvs_dgram_get_cid(struct sk_buff *skb, unsigned int *cid) >> +{ >> + return -EOPNOTSUPP; >> +} >> + >> +static int hvs_dgram_get_port(struct sk_buff *skb, unsigned int *port) >> +{ >> + return -EOPNOTSUPP; >> +} >> + >> +static int hvs_dgram_get_length(struct sk_buff *skb, size_t *len) >> { >> return -EOPNOTSUPP; >> } >> @@ -833,7 +842,9 @@ static struct vsock_transport hvs_transport = { >> .shutdown = hvs_shutdown, >> >> .dgram_bind = hvs_dgram_bind, >> - .dgram_dequeue = hvs_dgram_dequeue, >> + .dgram_get_cid = hvs_dgram_get_cid, >> + .dgram_get_port = hvs_dgram_get_port, >> + .dgram_get_length = hvs_dgram_get_length, >> .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 e95df847176b..5763cdf13804 100644 >> --- a/net/vmw_vsock/virtio_transport.c >> +++ b/net/vmw_vsock/virtio_transport.c >> @@ -429,9 +429,11 @@ 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, >> + .dgram_get_cid = virtio_transport_dgram_get_cid, >> + .dgram_get_port = virtio_transport_dgram_get_port, >> + .dgram_get_length = virtio_transport_dgram_get_length, >> >> .stream_dequeue = virtio_transport_stream_dequeue, >> .stream_enqueue = virtio_transport_stream_enqueue, >> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c >> index b769fc258931..e6903c719964 100644 >> --- a/net/vmw_vsock/virtio_transport_common.c >> +++ b/net/vmw_vsock/virtio_transport_common.c >> @@ -797,6 +797,24 @@ int virtio_transport_dgram_bind(struct vsock_sock *vsk, >> } >> EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind); >> >> +int virtio_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid) >> +{ >> + return -EOPNOTSUPP; >> +} >> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_cid); >> + >> +int virtio_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port) >> +{ >> + return -EOPNOTSUPP; >> +} >> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_port); >> + >> +int virtio_transport_dgram_get_length(struct sk_buff *skb, size_t *len) >> +{ >> + return -EOPNOTSUPP; >> +} >> +EXPORT_SYMBOL_GPL(virtio_transport_dgram_get_length); >> + >> bool virtio_transport_dgram_allow(u32 cid, u32 port) >> { >> return false; >> diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c >> index b370070194fa..bbc63826bf48 100644 >> --- a/net/vmw_vsock/vmci_transport.c >> +++ b/net/vmw_vsock/vmci_transport.c >> @@ -1731,57 +1731,40 @@ 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) >> +static int vmci_transport_dgram_get_cid(struct sk_buff *skb, unsigned int *cid) >> { >> - int err; >> struct vmci_datagram *dg; >> - size_t payload_len; >> - struct sk_buff *skb; >> >> - if (flags & MSG_OOB || flags & MSG_ERRQUEUE) >> - return -EOPNOTSUPP; >> + dg = (struct vmci_datagram *)skb->data; >> + if (!dg) >> + return -EINVAL; >> >> - /* 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; >> + *cid = dg->src.context; >> + return 0; >> +} >> + >> +static int vmci_transport_dgram_get_port(struct sk_buff *skb, unsigned int *port) >> +{ >> + struct vmci_datagram *dg; >> >> 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; >> - } >> + return -EINVAL; >> >> - if (payload_len > len) { >> - payload_len = len; >> - msg->msg_flags |= MSG_TRUNC; >> - } >> + *port = dg->src.resource; >> + return 0; >> +} >> >> - /* Place the datagram payload in the user's iovec. */ >> - err = skb_copy_datagram_msg(skb, sizeof(*dg), msg, payload_len); >> - if (err) >> - goto out; >> +static int vmci_transport_dgram_get_length(struct sk_buff *skb, size_t *len) >> +{ >> + struct vmci_datagram *dg; >> >> - 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; >> + dg = (struct vmci_datagram *)skb->data; >> + if (!dg) >> + return -EINVAL; >> >> -out: >> - skb_free_datagram(&vsk->sk, skb); >> - return err; >> + *len = dg->payload_size; >> + return 0; >> } >> >> static bool vmci_transport_dgram_allow(u32 cid, u32 port) >> @@ -2040,9 +2023,12 @@ 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, >> + .dgram_get_cid = vmci_transport_dgram_get_cid, >> + .dgram_get_port = vmci_transport_dgram_get_port, >> + .dgram_get_length = vmci_transport_dgram_get_length, >> + .dgram_payload_offset = sizeof(struct vmci_datagram), >> .stream_dequeue = vmci_transport_stream_dequeue, >> .stream_enqueue = vmci_transport_stream_enqueue, >> .stream_has_data = vmci_transport_stream_has_data, >> diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c >> index 5c6360df1f31..2f3cabc79ee5 100644 >> --- a/net/vmw_vsock/vsock_loopback.c >> +++ b/net/vmw_vsock/vsock_loopback.c >> @@ -62,9 +62,11 @@ 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, >> + .dgram_get_cid = virtio_transport_dgram_get_cid, >> + .dgram_get_port = virtio_transport_dgram_get_port, >> + .dgram_get_length = virtio_transport_dgram_get_length, >> >> .stream_dequeue = virtio_transport_stream_dequeue, >> .stream_enqueue = virtio_transport_stream_enqueue, >> >