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

From: Pavel Begunkov
Date: Mon Jun 19 2023 - 05:30:29 EST


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 believe Breno wants to extend it
later to support more operations.

Sockets are a large chunk of use cases, it can be implemented as a
separate io_uring request type if nothing else works, but in general
that might not be as scalable.

--
Pavel Begunkov