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

From: Kanchan Joshi <[email-masked]>
Date: Mon, 19 Jun 2023 19:36:35 +0530

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.