net: Remove the err argument from sock_from_file

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@zeniv.linux.org.uk>
Signed-off-by: Florent Revest <revest@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20201204113609.1850150-1-revest@google.com

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 73c346e..19499b7 100644 (file)
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -416,12 +416,11 @@ 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 1023f7b..7942a42 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4356,9 +4356,9 @@ 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;
@@ -4405,9 +4405,9 @@ 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))
@@ -4584,9 +4584,9 @@ 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;
@@ -4647,9 +4647,9 @@ 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 0dcd51f..9e2324e 100644 (file)
--- 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 41b24cd..b49c57d 100644 (file)
--- 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 9bd4cab..99a431c 100644 (file)
--- 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 4fd7e78..bbcd4b9 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2827,14 +2827,8 @@ 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 bfef11b..9a240b4 100644 (file)
--- 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;
@@ -1693,9 +1694,11 @@ 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();
@@ -1818,9 +1821,11 @@ 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);