net: Introduce possible_net_t

Having to say
> #ifdef CONFIG_NET_NS
> 	struct net *net;
> #endif

in structures is a little bit wordy and a little bit error prone.

Instead it is possible to say:
> typedef struct {
> #ifdef CONFIG_NET_NS
>       struct net *net;
> #endif
> } possible_net_t;

And then in a header say:

> 	possible_net_t net;

Which is cleaner and easier to use and easier to test, as the
possible_net_t is always there no matter what the compile options.

Further this allows read_pnet and write_pnet to be functions in all
cases which is better at catching typos.

This change adds possible_net_t, updates the definitions of read_pnet
and write_pnet, updates optional struct net * variables that
write_pnet uses on to have the type possible_net_t, and finally fixes
up the b0rked users of read_pnet and write_pnet.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 80d08f6664cb..3e3d82d8ff70 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -940,7 +940,7 @@ p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
         sin_server.sin_family = AF_INET;
         sin_server.sin_addr.s_addr = in_aton(addr);
         sin_server.sin_port = htons(opts.port);
-        err = __sock_create(read_pnet(&current->nsproxy->net_ns), PF_INET,
+        err = __sock_create(current->nsproxy->net_ns, PF_INET,
                             SOCK_STREAM, IPPROTO_TCP, &csocket, 1);
         if (err) {
                 pr_err("%s (%d): problem creating socket\n",
@@ -988,7 +988,7 @@ p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
 
         sun_server.sun_family = PF_UNIX;
         strcpy(sun_server.sun_path, addr);
-        err = __sock_create(read_pnet(&current->nsproxy->net_ns), PF_UNIX,
+        err = __sock_create(current->nsproxy->net_ns, PF_UNIX,
                             SOCK_STREAM, 0, &csocket, 1);
         if (err < 0) {
                 pr_err("%s (%d): problem creating socket\n",