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authorEric W. Biederman <ebiederm@xmission.com>2013-03-09 16:15:23 -0800
committerEric W. Biederman <ebiederm@xmission.com>2013-08-30 17:30:38 -0700
commitdbef0c1c4c5f8ce5d1f5bd8cee092a7afb4ac21b (patch)
tree3eaa0a5a45ba52fae938e42e0031f25ac96a482f
parenta606488513543312805fab2b93070cefe6a3016c (diff)
namespaces: Simplify copy_namespaces so it is clear what is going on.
Remove the test for the impossible case where tsk->nsproxy == NULL. Fork will never be called with tsk->nsproxy == NULL. Only call get_nsproxy when we don't need to generate a new_nsproxy, and mark the case where we don't generate a new nsproxy as likely. Remove the code to drop an unnecessarily acquired nsproxy value. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
-rw-r--r--kernel/nsproxy.c35
1 files changed, 11 insertions, 24 deletions
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index d9afd256318f..a1ed01139276 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -125,22 +125,16 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
struct nsproxy *old_ns = tsk->nsproxy;
struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
struct nsproxy *new_ns;
- int err = 0;
- if (!old_ns)
+ if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+ CLONE_NEWPID | CLONE_NEWNET)))) {
+ get_nsproxy(old_ns);
return 0;
-
- get_nsproxy(old_ns);
-
- if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))
- return 0;
-
- if (!ns_capable(user_ns, CAP_SYS_ADMIN)) {
- err = -EPERM;
- goto out;
}
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
/*
* CLONE_NEWIPC must detach from the undolist: after switching
* to a new ipc namespace, the semaphore arrays from the old
@@ -149,22 +143,15 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
* it along with CLONE_NEWIPC.
*/
if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
- (CLONE_NEWIPC | CLONE_SYSVSEM)) {
- err = -EINVAL;
- goto out;
- }
+ (CLONE_NEWIPC | CLONE_SYSVSEM))
+ return -EINVAL;
new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
- if (IS_ERR(new_ns)) {
- err = PTR_ERR(new_ns);
- goto out;
- }
+ if (IS_ERR(new_ns))
+ return PTR_ERR(new_ns);
tsk->nsproxy = new_ns;
-
-out:
- put_nsproxy(old_ns);
- return err;
+ return 0;
}
void free_nsproxy(struct nsproxy *ns)