On Wed, Aug 03, 2022 at 01:51:05PM +0000, Arseniy Krasnov wrote:
This adds transport specific callback for SO_RCVLOWAT, because in some
transports it may be difficult to know current available number of bytes
ready to read. Thus, when SO_RCVLOWAT is set, transport may reject it.
Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
---
include/net/af_vsock.h | 1 +
net/vmw_vsock/af_vsock.c | 25 +++++++++++++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index f742e50207fb..eae5874bae35 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -134,6 +134,7 @@ struct vsock_transport {
u64 (*stream_rcvhiwat)(struct vsock_sock *);
bool (*stream_is_active)(struct vsock_sock *);
bool (*stream_allow)(u32 cid, u32 port);
+ int (*set_rcvlowat)(struct vsock_sock *, int);
checkpatch suggests to add identifier names. For some we put them in,
for others we didn't, but I suggest putting them in for the new ones
because I think it's clearer too.
WARNING: function definition argument 'struct vsock_sock *' should also
have an identifier name
#25: FILE: include/net/af_vsock.h:137:
+ int (*set_rcvlowat)(struct vsock_sock *, int);
WARNING: function definition argument 'int' should also have an identifier name
#25: FILE: include/net/af_vsock.h:137:
+ int (*set_rcvlowat)(struct vsock_sock *, int);
total: 0 errors, 2 warnings, 0 checks, 44 lines checked
/* SEQ_PACKET. */
ssize_t (*seqpacket_dequeue)(struct vsock_sock *vsk, struct msghdr *msg,
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index f04abf662ec6..016ad5ff78b7 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -2129,6 +2129,30 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
return err;
}
+static int vsock_set_rcvlowat(struct sock *sk, int val)
+{
+ const struct vsock_transport *transport;
+ struct vsock_sock *vsk;
+ int err = 0;
+
+ vsk = vsock_sk(sk);
+
+ if (val > vsk->buffer_size)
+ return -EINVAL;
+
+ transport = vsk->transport;
+
+ if (!transport)
+ return -EOPNOTSUPP;
I don't know whether it is better in this case to write it in
sk->sk_rcvlowat, maybe we can return EOPNOTSUPP only when the trasport
is assigned and set_rcvlowat is not defined. This is because usually the
options are set just after creation, when the transport is practically
unassigned.
I mean something like this:
if (transport) {
if (transport->set_rcvlowat)
return transport->set_rcvlowat(vsk, val);
else
return -EOPNOTSUPP;
}
WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
return 0;
+
+ if (transport->set_rcvlowat)
+ err = transport->set_rcvlowat(vsk, val);
+ else
+ WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
+
+ return err;
+}
+
static const struct proto_ops vsock_stream_ops = {
.family = PF_VSOCK,
.owner = THIS_MODULE,
@@ -2148,6 +2172,7 @@ static const struct proto_ops vsock_stream_ops = {
.recvmsg = vsock_connectible_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
+ .set_rcvlowat = vsock_set_rcvlowat,
};
static const struct proto_ops vsock_seqpacket_ops = {
--
2.25.1
