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From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>,
	[email protected], Josh Triplett <[email protected]>
Cc: "David S . Miller" <[email protected]>,
	Jakub Kicinski <[email protected]>,
	[email protected], [email protected],
	Stefan Metzmacher <[email protected]>
Subject: [PATCH v4 1/4] net: add accept helper not installing fd
Date: Wed, 25 Aug 2021 12:25:44 +0100	[thread overview]
Message-ID: <c57b9e8e818d93683a3d24f8ca50ca038d1da8c4.1629888991.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>

Introduce and reuse a helper that acts similarly to __sys_accept4_file()
but returns struct file instead of installing file descriptor. Will be
used by io_uring.

Signed-off-by: Pavel Begunkov <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
 include/linux/socket.h |  3 ++
 net/socket.c           | 71 ++++++++++++++++++++++--------------------
 2 files changed, 40 insertions(+), 34 deletions(-)

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 0d8e3dcb7f88..d3c1a42a2edd 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -421,6 +421,9 @@ extern int __sys_accept4_file(struct file *file, unsigned file_flags,
 			struct sockaddr __user *upeer_sockaddr,
 			 int __user *upeer_addrlen, int flags,
 			 unsigned long nofile);
+extern struct file *do_accept(struct file *file, unsigned file_flags,
+			      struct sockaddr __user *upeer_sockaddr,
+			      int __user *upeer_addrlen, int flags);
 extern int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
 			 int __user *upeer_addrlen, int flags);
 extern int __sys_socket(int family, int type, int protocol);
diff --git a/net/socket.c b/net/socket.c
index 0b2dad3bdf7f..532fff5a3684 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1722,32 +1722,22 @@ SYSCALL_DEFINE2(listen, int, fd, int, backlog)
 	return __sys_listen(fd, backlog);
 }
 
-int __sys_accept4_file(struct file *file, unsigned file_flags,
+struct file *do_accept(struct file *file, unsigned file_flags,
 		       struct sockaddr __user *upeer_sockaddr,
-		       int __user *upeer_addrlen, int flags,
-		       unsigned long nofile)
+		       int __user *upeer_addrlen, int flags)
 {
 	struct socket *sock, *newsock;
 	struct file *newfile;
-	int err, len, newfd;
+	int err, len;
 	struct sockaddr_storage address;
 
-	if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
-		return -EINVAL;
-
-	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
-		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
-
 	sock = sock_from_file(file);
-	if (!sock) {
-		err = -ENOTSOCK;
-		goto out;
-	}
+	if (!sock)
+		return ERR_PTR(-ENOTSOCK);
 
-	err = -ENFILE;
 	newsock = sock_alloc();
 	if (!newsock)
-		goto out;
+		return ERR_PTR(-ENFILE);
 
 	newsock->type = sock->type;
 	newsock->ops = sock->ops;
@@ -1758,18 +1748,9 @@ int __sys_accept4_file(struct file *file, unsigned file_flags,
 	 */
 	__module_get(newsock->ops->owner);
 
-	newfd = __get_unused_fd_flags(flags, nofile);
-	if (unlikely(newfd < 0)) {
-		err = newfd;
-		sock_release(newsock);
-		goto out;
-	}
 	newfile = sock_alloc_file(newsock, flags, sock->sk->sk_prot_creator->name);
-	if (IS_ERR(newfile)) {
-		err = PTR_ERR(newfile);
-		put_unused_fd(newfd);
-		goto out;
-	}
+	if (IS_ERR(newfile))
+		return newfile;
 
 	err = security_socket_accept(sock, newsock);
 	if (err)
@@ -1794,16 +1775,38 @@ int __sys_accept4_file(struct file *file, unsigned file_flags,
 	}
 
 	/* File flags are not inherited via accept() unlike another OSes. */
-
-	fd_install(newfd, newfile);
-	err = newfd;
-out:
-	return err;
+	return newfile;
 out_fd:
 	fput(newfile);
-	put_unused_fd(newfd);
-	goto out;
+	return ERR_PTR(err);
+}
+
+int __sys_accept4_file(struct file *file, unsigned file_flags,
+		       struct sockaddr __user *upeer_sockaddr,
+		       int __user *upeer_addrlen, int flags,
+		       unsigned long nofile)
+{
+	struct file *newfile;
+	int newfd;
 
+	if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
+		return -EINVAL;
+
+	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
+		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
+
+	newfd = __get_unused_fd_flags(flags, nofile);
+	if (unlikely(newfd < 0))
+		return newfd;
+
+	newfile = do_accept(file, file_flags, upeer_sockaddr, upeer_addrlen,
+			    flags);
+	if (IS_ERR(newfile)) {
+		put_unused_fd(newfd);
+		return PTR_ERR(newfile);
+	}
+	fd_install(newfd, newfile);
+	return newfd;
 }
 
 /*
-- 
2.32.0


  reply	other threads:[~2021-08-25 11:26 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-25 11:25 [PATCH v4 0/4] open/accept directly into io_uring fixed file table Pavel Begunkov
2021-08-25 11:25 ` Pavel Begunkov [this message]
2021-08-25 12:32   ` [PATCH v4 1/4] net: add accept helper not installing fd David Miller
2021-08-25 11:25 ` [PATCH v4 2/4] io_uring: openat directly into fixed fd table Pavel Begunkov
2021-08-25 11:25 ` [PATCH v4 3/4] io_uring: hand code io_accept() fd installing Pavel Begunkov
2021-08-25 11:25 ` [PATCH v4 4/4] io_uring: accept directly into fixed file table Pavel Begunkov
2021-08-25 15:00 ` [PATCH v4 0/4] open/accept directly into io_uring " Jens Axboe

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