[PATCH] uts: copy nsproxy only when needed
The nsproxy was being copied in unshare() when anything was being unshared,
even if it was something not referenced from nsproxy. This should end up
in some cases with far more memory usage than necessary.
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index c08cf05..208dd99 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1606,7 +1606,7 @@
struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
struct files_struct *fd, *new_fd = NULL;
struct sem_undo_list *new_ulist = NULL;
- struct nsproxy *new_nsproxy, *old_nsproxy;
+ struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL;
struct uts_namespace *uts, *new_uts = NULL;
check_unshare_flags(&unshare_flags);
@@ -1634,18 +1634,24 @@
if ((err = unshare_utsname(unshare_flags, &new_uts)))
goto bad_unshare_cleanup_semundo;
- if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist ||
- new_uts) {
-
+ if (new_ns || new_uts) {
old_nsproxy = current->nsproxy;
new_nsproxy = dup_namespaces(old_nsproxy);
if (!new_nsproxy) {
err = -ENOMEM;
goto bad_unshare_cleanup_uts;
}
+ }
+
+ if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist ||
+ new_uts) {
task_lock(current);
- current->nsproxy = new_nsproxy;
+
+ if (new_nsproxy) {
+ current->nsproxy = new_nsproxy;
+ new_nsproxy = old_nsproxy;
+ }
if (new_fs) {
fs = current->fs;
@@ -1687,9 +1693,11 @@
}
task_unlock(current);
- put_nsproxy(old_nsproxy);
}
+ if (new_nsproxy)
+ put_nsproxy(new_nsproxy);
+
bad_unshare_cleanup_uts:
if (new_uts)
put_uts_ns(new_uts);