[NET]: Make /proc/net per network namespace

This patch makes /proc/net per network namespace.  It modifies the global
variables proc_net and proc_net_stat to be per network namespace.
The proc_net file helpers are modified to take a network namespace argument,
and all of their callers are fixed to pass &init_net for that argument.
This ensures that all of the /proc/net files are only visible and
usable in the initial network namespace until the code behind them
has been updated to be handle multiple network namespaces.

Making /proc/net per namespace is necessary as at least some files
in /proc/net depend upon the set of network devices which is per
network namespace, and even more files in /proc/net have contents
that are relevant to a single network namespace.

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

3 files changed, 9 insertions, 5 deletions

diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index bce38e3f06cb..ebaba0213546 100644
--- a/fs/proc/Makefile
+++ b/fs/proc/Makefile
@@ -11,6 +11,7 @@ proc-y       += inode.o root.o base.o generic.o array.o \
                 proc_tty.o proc_misc.o
 
 proc-$(CONFIG_PROC_SYSCTL)      += proc_sysctl.o
+proc-$(CONFIG_NET)              += proc_net.o
 proc-$(CONFIG_PROC_KCORE)       += kcore.o
 proc-$(CONFIG_PROC_VMCORE)      += vmcore.o
 proc-$(CONFIG_PROC_DEVICETREE)  += proc_devtree.o
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index b215c3524fa6..1820eb2ef762 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -16,6 +16,11 @@ extern int proc_sys_init(void);
 #else
 static inline void proc_sys_init(void) { }
 #endif
+#ifdef CONFIG_NET
+extern int proc_net_init(void);
+#else
+static inline int proc_net_init(void) { return 0; }
+#endif
 
 struct vmalloc_info {
         unsigned long   used;
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 41f17037f738..cf3046638b09 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -21,7 +21,7 @@
 
 #include "internal.h"
 
-struct proc_dir_entry *proc_net, *proc_net_stat, *proc_bus, *proc_root_fs, *proc_root_driver;
+struct proc_dir_entry *proc_bus, *proc_root_fs, *proc_root_driver;
 
 static int proc_get_sb(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
@@ -61,8 +61,8 @@ void __init proc_root_init(void)
                 return;
         }
         proc_misc_init();
-        proc_net = proc_mkdir("net", NULL);
-        proc_net_stat = proc_mkdir("net/stat", NULL);
+
+        proc_net_init();
 
 #ifdef CONFIG_SYSVIPC
         proc_mkdir("sysvipc", NULL);
@@ -159,7 +159,5 @@ EXPORT_SYMBOL(create_proc_entry);
 EXPORT_SYMBOL(remove_proc_entry);
 EXPORT_SYMBOL(proc_root);
 EXPORT_SYMBOL(proc_root_fs);
-EXPORT_SYMBOL(proc_net);
-EXPORT_SYMBOL(proc_net_stat);
 EXPORT_SYMBOL(proc_bus);
 EXPORT_SYMBOL(proc_root_driver);