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

Breno Leitao
2023-04-06T14:46:10Z

Create the initial plumbing to call protocol specific uring_cmd
callbacks. These are io_uring specific callbacks that implement
ioctl-like operation types, such as SIOCINQ, SIOCOUTQ and others.

In order to achieve this, create uring_cmd callback placeholders in
file_ops, proto and proto_ops structures.

Create also the functions that does the plumbing from io_uring_cmd() up
to sk_proto->uring_cmd(). If the callback is not implemented,
-EOPNOTSUPP is returned.

That way, the io_uring issue path calls file_operations->uring_cmd
(sock_uring_cmd()). This function calls proto_ops->uring_cmd
(sock_common_uring_cmd()). sock_common_uring_cmd() is responsible for
calling protocol specific (struct proto_ops) uring_cmd callback
(sock_common_uring_cmd()). sock_common_uring_cmd() then calls the proto
specific (struct proto) uring_cmd function, which are implemented in the
upcoming patch.

By the end, uring_cmd() function has access to 'struct io_uring_cmd'
which points to the whole SQE, and any field could be accessed from the
function pointer.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
include/linux/net.h | 2 ++
include/net/sock.h | 6 ++++++
net/core/sock.c | 17 +++++++++++++++--
net/dccp/ipv4.c | 1 +
net/ipv4/af_inet.c | 3 +++
net/l2tp/l2tp_ip.c | 1 +
net/mptcp/protocol.c | 1 +
net/sctp/protocol.c | 1 +
net/socket.c | 13 +++++++++++++
9 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/include/linux/net.h b/include/linux/net.h
index b73ad8e3c212..efcc47a57069 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 573f2bf7e0de..57437a1e041c 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;
@@ -1247,6 +1248,9 @@ struct proto {

int (*ioctl)(struct sock *sk, int cmd,
unsigned long arg);
+ 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);
@@ -1921,6 +1925,8 @@ 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 c25888795390..1bf5e4d4ba29 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3669,6 +3669,18 @@ 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);
+
void sk_common_release(struct sock *sk)
{
if (sk->sk_prot->destroy)
@@ -4009,7 +4021,7 @@ static void proto_seq_printf(struct seq_file *seq, struct proto *proto)
{

seq_printf(seq, "%-9s %4u %6d %6ld %-3s %6u %-3s %-10s "
- "%2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c\n",
+ "%2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c\n",
proto->name,
proto->obj_size,
sock_prot_inuse_get(seq_file_net(seq), proto),
@@ -4023,6 +4035,7 @@ static void proto_seq_printf(struct seq_file *seq, struct proto *proto)
proto_method_implemented(proto->disconnect),
proto_method_implemented(proto->accept),
proto_method_implemented(proto->ioctl),
+ proto_method_implemented(proto->uring_cmd),
proto_method_implemented(proto->init),
proto_method_implemented(proto->destroy),
proto_method_implemented(proto->shutdown),
@@ -4051,7 +4064,7 @@ static int proto_seq_show(struct seq_file *seq, void *v)
"maxhdr",
"slab",
"module",
- "cl co di ac io in de sh ss gs se re sp bi br ha uh gp em\n");
+ "cl co di ac io ur in de sh ss gs se re sp bi br ha uh gp em\n");
else
proto_seq_printf(seq, list_entry(v, struct proto, node));
return 0;
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index b780827f5e0a..47047ad05e65 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -999,6 +999,7 @@ static const struct proto_ops inet_dccp_ops = {
/* FIXME: work on tcp_poll to rename it to inet_csk_poll */
.poll = dccp_poll,
.ioctl = inet_ioctl,
+ .uring_cmd = sock_common_uring_cmd,
.gettstamp = sock_gettstamp,
/* FIXME: work on inet_listen to rename it to sock_common_listen */
.listen = inet_dccp_listen,
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 8db6747f892f..1c54c3b59f2e 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1036,6 +1036,7 @@ const struct proto_ops inet_stream_ops = {
.getname = inet_getname,
.poll = tcp_poll,
.ioctl = inet_ioctl,
+ .uring_cmd = sock_common_uring_cmd,
.gettstamp = sock_gettstamp,
.listen = inet_listen,
.shutdown = inet_shutdown,
@@ -1071,6 +1072,7 @@ const struct proto_ops inet_dgram_ops = {
.getname = inet_getname,
.poll = udp_poll,
.ioctl = inet_ioctl,
+ .uring_cmd = sock_common_uring_cmd,
.gettstamp = sock_gettstamp,
.listen = sock_no_listen,
.shutdown = inet_shutdown,
@@ -1103,6 +1105,7 @@ static const struct proto_ops inet_sockraw_ops = {
.getname = inet_getname,
.poll = datagram_poll,
.ioctl = inet_ioctl,
+ .uring_cmd = sock_common_uring_cmd,
.gettstamp = sock_gettstamp,
.listen = sock_no_listen,
.shutdown = inet_shutdown,
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 4db5a554bdbd..cdfaaada0695 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -617,6 +617,7 @@ static const struct proto_ops l2tp_ip_ops = {
.getname = l2tp_ip_getname,
.poll = datagram_poll,
.ioctl = inet_ioctl,
+ .uring_cmd = sock_common_uring_cmd,
.gettstamp = sock_gettstamp,
.listen = sock_no_listen,
.shutdown = inet_shutdown,
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 3ad9c46202fc..b8182eab5ebf 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3808,6 +3808,7 @@ static const struct proto_ops mptcp_stream_ops = {
.getname = inet_getname,
.poll = mptcp_poll,
.ioctl = inet_ioctl,
+ .uring_cmd = sock_common_uring_cmd,
.gettstamp = sock_gettstamp,
.listen = mptcp_listen,
.shutdown = inet_shutdown,
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index c365df24ad33..b1aaf644076f 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1127,6 +1127,7 @@ static const struct proto_ops inet_seqpacket_ops = {
.getname = inet_getname, /* Semantics are different. */
.poll = sctp_poll,
.ioctl = inet_ioctl,
+ .uring_cmd = sock_common_uring_cmd,
.gettstamp = sock_gettstamp,
.listen = sctp_inet_listen,
.shutdown = inet_shutdown, /* Looks harmless. */
diff --git a/net/socket.c b/net/socket.c
index 9c92c0e6c4da..c683110c1523 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -87,6 +87,7 @@
#include <linux/xattr.h>
#include <linux/nospec.h>
#include <linux/indirect_call_wrapper.h>
+#include <linux/io_uring.h>

#include <linux/uaccess.h>
#include <asm/unistd.h>
@@ -116,6 +117,7 @@ unsigned int sysctl_net_busy_poll __read_mostly;
static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to);
static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from);
static int sock_mmap(struct file *file, struct vm_area_struct *vma);
+static int sock_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags);

static int sock_close(struct inode *inode, struct file *file);
static __poll_t sock_poll(struct file *file,
@@ -159,6 +161,7 @@ static const struct file_operations socket_file_ops = {
#ifdef CONFIG_COMPAT
.compat_ioctl = compat_sock_ioctl,
#endif
+ .uring_cmd = sock_uring_cmd,
.mmap = sock_mmap,
.release = sock_close,
.fasync = sock_fasync,
@@ -1319,6 +1322,16 @@ static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
return err;
}

+static int sock_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
+{
+ struct socket *sock = cmd->file->private_data;
+
+ if (!sock->ops || !sock->ops->uring_cmd)
+ return -EOPNOTSUPP;
+
+ return sock->ops->uring_cmd(sock, cmd, issue_flags);
+}
+
/**
* sock_create_lite - creates a socket
* @family: protocol family (AF_INET, ...)
--
2.34.1