Re: [RFC PATCH v2 1/4] net: wire up support for file_operations->uring_cmd()

[Kanchan Joshi <joshi.k@xxxxxxxxxxx>]

On Mon, Jun 19, 2023 at 10:28:30AM +0100, Pavel Begunkov wrote:
> On 6/14/23 16:15, David Ahern wrote:
> > On 6/14/23 5:07 AM, Breno Leitao wrote:
> > > diff --git a/include/linux/net.h b/include/linux/net.h
> > > index 8defc8f1d82e..58dea87077af 100644
> > > --- a/include/linux/net.h
> > > +++ b/include/linux/net.h
> > > @@ -182,6 +182,8 @@ struct proto_ops {
> > >  	int	 	(*compat_ioctl) (struct socket *sock, unsigned int cmd,
> > >  				      unsigned long arg);
> > >  #endif
> > > +	int		(*uring_cmd)(struct socket *sock, struct io_uring_cmd *cmd,
> > > +				     unsigned int issue_flags);
> > >  	int		(*gettstamp) (struct socket *sock, void __user *userstamp,
> > >  				      bool timeval, bool time32);
> > >  	int		(*listen)    (struct socket *sock, int len);
> > > diff --git a/include/net/sock.h b/include/net/sock.h
> > > index 62a1b99da349..a49b8b19292b 100644
> > > --- a/include/net/sock.h
> > > +++ b/include/net/sock.h
> > > @@ -111,6 +111,7 @@ typedef struct {
> > >  struct sock;
> > >  struct proto;
> > >  struct net;
> > > +struct io_uring_cmd;
> > >  typedef __u32 __bitwise __portpair;
> > >  typedef __u64 __bitwise __addrpair;
> > > @@ -1259,6 +1260,9 @@ struct proto {
> > >  	int			(*ioctl)(struct sock *sk, int cmd,
> > >  					 int *karg);
> > > +	int			(*uring_cmd)(struct sock *sk,
> > > +					     struct io_uring_cmd *cmd,
> > > +					     unsigned int issue_flags);
> > >  	int			(*init)(struct sock *sk);
> > >  	void			(*destroy)(struct sock *sk);
> > >  	void			(*shutdown)(struct sock *sk, int how);
> > > @@ -1934,6 +1938,8 @@ int sock_common_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
> > >  			int flags);
> > >  int sock_common_setsockopt(struct socket *sock, int level, int optname,
> > >  			   sockptr_t optval, unsigned int optlen);
> > > +int sock_common_uring_cmd(struct socket *sock, struct io_uring_cmd *cmd,
> > > +			  unsigned int issue_flags);
> > >  void sk_common_release(struct sock *sk);
> > > diff --git a/net/core/sock.c b/net/core/sock.c
> > > index 1df7e432fec5..339fa74db60f 100644
> > > --- a/net/core/sock.c
> > > +++ b/net/core/sock.c
> > > @@ -3668,6 +3668,18 @@ int sock_common_setsockopt(struct socket *sock, int level, int optname,
> > >  }
> > >  EXPORT_SYMBOL(sock_common_setsockopt);
> > > +int sock_common_uring_cmd(struct socket *sock, struct io_uring_cmd *cmd,
> > > +			  unsigned int issue_flags)
> > > +{
> > > +	struct sock *sk = sock->sk;
> > > +
> > > +	if (!sk->sk_prot || !sk->sk_prot->uring_cmd)
> > > +		return -EOPNOTSUPP;
> > > +
> > > +	return sk->sk_prot->uring_cmd(sk, cmd, issue_flags);
> > > +}
> > > +EXPORT_SYMBOL(sock_common_uring_cmd);
> > > +
> >
> >
> > io_uring is just another in-kernel user of sockets. There is no reason
> > for io_uring references to be in core net code. It should be using
> > exposed in-kernel APIs and doing any translation of its op codes in
> > io_uring/  code.
>
> That callback is all about file dependent operations, just like ioctl.
> And as the patch in question is doing socket specific stuff, I think
> architecturally it fits well. 

I also feel that it fits well.
Other users of uring-cmd (nvme, ublk) follow the same model.