[PATCH net-next 1/2] socket: Allow external sockets to use socket syscalls

From: Alex Gartrell
Date: Fri Dec 26 2014 - 01:51:33 EST


Currently the "is-socket" test for a file compares the ops table pointer,
which is static and local to the socket.c. Instead, this adds a flag for
private_data_is_socket. This is an exceptionally long commit message for a
two-line patch.

Signed-off-by: Alex Gartrell <agartrell@xxxxxx>
---
include/linux/fs.h | 2 +-
net/socket.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index bb29b02..d162476 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -809,7 +809,7 @@ struct file {
#endif
/* needed for tty driver, and maybe others */
void *private_data;
-
+ bool private_data_is_socket : 1;
#ifdef CONFIG_EPOLL
/* Used by fs/eventpoll.c to link all the hooks to this file */
struct list_head f_ep_links;
diff --git a/net/socket.c b/net/socket.c
index 8809afc..cd853be 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -388,6 +388,7 @@ struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname)
sock->file = file;
file->f_flags = O_RDWR | (flags & O_NONBLOCK);
file->private_data = sock;
+ file->private_data_is_socket = true;
return file;
}
EXPORT_SYMBOL(sock_alloc_file);
@@ -411,7 +412,7 @@ static int sock_map_fd(struct socket *sock, int flags)

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

*err = -ENOTSOCK;
--
Alex Gartrell <agartrell@xxxxxx>

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