[PATCH v2 1/5] net: Remove the err argument from sock_from_file

From: Florent Revest
Date: Thu Nov 19 2020 - 11:27:36 EST


From: Florent Revest <revest@xxxxxxxxxx>

Currently, the sock_from_file prototype takes an "err" pointer that is
either not set or set to -ENOTSOCK IFF the returned socket is NULL. This
makes the error redundant and it is ignored by a few callers.

This patch simplifies the API by letting callers deduce the error based
on whether the returned socket is NULL or not.

Suggested-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Florent Revest <revest@xxxxxxxxxx>
---
fs/eventpoll.c | 3 +--
fs/io_uring.c | 16 ++++++++--------
include/linux/net.h | 2 +-
net/core/netclassid_cgroup.c | 3 +--
net/core/netprio_cgroup.c | 3 +--
net/core/sock.c | 8 +-------
net/socket.c | 27 ++++++++++++++++-----------
7 files changed, 29 insertions(+), 33 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 4df61129566d..c764d8d5a76a 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -415,12 +415,11 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
unsigned int napi_id;
struct socket *sock;
struct sock *sk;
- int err;

if (!net_busy_loop_on())
return;

- sock = sock_from_file(epi->ffd.file, &err);
+ sock = sock_from_file(epi->ffd.file);
if (!sock)
return;

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8018c7076b25..ace99b15cbd3 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4341,9 +4341,9 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret;

- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;

if (req->async_data) {
kmsg = req->async_data;
@@ -4390,9 +4390,9 @@ static int io_send(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret;

- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;

ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
if (unlikely(ret))
@@ -4569,9 +4569,9 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret, cflags = 0;

- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;

if (req->async_data) {
kmsg = req->async_data;
@@ -4632,9 +4632,9 @@ static int io_recv(struct io_kiocb *req, bool force_nonblock,
unsigned flags;
int ret, cflags = 0;

- sock = sock_from_file(req->file, &ret);
+ sock = sock_from_file(req->file);
if (unlikely(!sock))
- return ret;
+ return -ENOTSOCK;

if (req->flags & REQ_F_BUFFER_SELECT) {
kbuf = io_recv_buffer_select(req, !force_nonblock);
diff --git a/include/linux/net.h b/include/linux/net.h
index 0dcd51feef02..9e2324efc26a 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -240,7 +240,7 @@ int sock_sendmsg(struct socket *sock, struct msghdr *msg);
int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags);
struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname);
struct socket *sockfd_lookup(int fd, int *err);
-struct socket *sock_from_file(struct file *file, int *err);
+struct socket *sock_from_file(struct file *file);
#define sockfd_put(sock) fput(sock->file)
int net_ratelimit(void);

diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
index 41b24cd31562..b49c57d35a88 100644
--- a/net/core/netclassid_cgroup.c
+++ b/net/core/netclassid_cgroup.c
@@ -68,9 +68,8 @@ struct update_classid_context {

static int update_classid_sock(const void *v, struct file *file, unsigned n)
{
- int err;
struct update_classid_context *ctx = (void *)v;
- struct socket *sock = sock_from_file(file, &err);
+ struct socket *sock = sock_from_file(file);

if (sock) {
spin_lock(&cgroup_sk_update_lock);
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 9bd4cab7d510..99a431c56f23 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -220,8 +220,7 @@ static ssize_t write_priomap(struct kernfs_open_file *of,

static int update_netprio(const void *v, struct file *file, unsigned n)
{
- int err;
- struct socket *sock = sock_from_file(file, &err);
+ struct socket *sock = sock_from_file(file);
if (sock) {
spin_lock(&cgroup_sk_update_lock);
sock_cgroup_set_prioidx(&sock->sk->sk_cgrp_data,
diff --git a/net/core/sock.c b/net/core/sock.c
index 727ea1cc633c..dd0598d831ef 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2808,14 +2808,8 @@ EXPORT_SYMBOL(sock_no_mmap);
void __receive_sock(struct file *file)
{
struct socket *sock;
- int error;

- /*
- * The resulting value of "error" is ignored here since we only
- * need to take action when the file is a socket and testing
- * "sock" for NULL is sufficient.
- */
- sock = sock_from_file(file, &error);
+ sock = sock_from_file(file);
if (sock) {
sock_update_netprioidx(&sock->sk->sk_cgrp_data);
sock_update_classid(&sock->sk->sk_cgrp_data);
diff --git a/net/socket.c b/net/socket.c
index 6e6cccc2104f..c799d9652a2c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -445,17 +445,15 @@ static int sock_map_fd(struct socket *sock, int flags)
/**
* sock_from_file - Return the &socket bounded to @file.
* @file: file
- * @err: pointer to an error code return
*
- * On failure returns %NULL and assigns -ENOTSOCK to @err.
+ * On failure returns %NULL.
*/

-struct socket *sock_from_file(struct file *file, int *err)
+struct socket *sock_from_file(struct file *file)
{
if (file->f_op == &socket_file_ops)
return file->private_data; /* set in sock_map_fd */

- *err = -ENOTSOCK;
return NULL;
}
EXPORT_SYMBOL(sock_from_file);
@@ -484,9 +482,11 @@ struct socket *sockfd_lookup(int fd, int *err)
return NULL;
}

- sock = sock_from_file(file, err);
- if (!sock)
+ sock = sock_from_file(file);
+ if (!sock) {
+ *err = -ENOTSOCK;
fput(file);
+ }
return sock;
}
EXPORT_SYMBOL(sockfd_lookup);
@@ -498,11 +498,12 @@ static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)

*err = -EBADF;
if (f.file) {
- sock = sock_from_file(f.file, err);
+ sock = sock_from_file(f.file);
if (likely(sock)) {
*fput_needed = f.flags & FDPUT_FPUT;
return sock;
}
+ *err = -ENOTSOCK;
fdput(f);
}
return NULL;
@@ -1715,9 +1716,11 @@ int __sys_accept4_file(struct file *file, unsigned file_flags,
if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;

- sock = sock_from_file(file, &err);
- if (!sock)
+ sock = sock_from_file(file);
+ if (!sock) {
+ err = -ENOTSOCK;
goto out;
+ }

err = -ENFILE;
newsock = sock_alloc();
@@ -1840,9 +1843,11 @@ int __sys_connect_file(struct file *file, struct sockaddr_storage *address,
struct socket *sock;
int err;

- sock = sock_from_file(file, &err);
- if (!sock)
+ sock = sock_from_file(file);
+ if (!sock) {
+ err = -ENOTSOCK;
goto out;
+ }

err =
security_socket_connect(sock, (struct sockaddr *)address, addrlen);
--
2.29.2.299.gdc1121823c-goog