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authorSerge Hallyn <serue@us.ibm.com>2006-10-02 02:18:18 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-02 07:57:22 -0700
commitc0b2fc316599d6cd875b6b8cafa67f03b9512b4d (patch)
tree6e03101b6692dfe3284de05a5f4fd5495d513ab3
parent071df104f808b8195c40643dcb4d060681742e29 (diff)
[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>
-rw-r--r--kernel/fork.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index c08cf05dd59..208dd99f13b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1606,7 +1606,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
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 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
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 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
}
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);