Messages in this thread | | | Date | Wed, 8 Oct 2014 14:57:40 +0000 | From | Serge Hallyn <> | Subject | Re: [PATCH RFC] setns: return 0 directly if try to reassociate with current namespace |
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Quoting Chen Hanxiao (chenhanxiao@cn.fujitsu.com): > We could use setns to join the current ns, > which did a lot of unnecessary work. > This patch will check this senario and > return 0 directly. > > Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
Plus it's just asking for trouble.
I would ack this, except you need to fclose(file) on the return paths. So just set err = 0 and goto out.
> --- > kernel/nsproxy.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c > index ef42d0a..66eea63 100644 > --- a/kernel/nsproxy.c > +++ b/kernel/nsproxy.c > @@ -236,6 +236,34 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype) > ops = ei->ns_ops; > if (nstype && (ops->type != nstype)) > goto out; > + switch (ops->type) { > + case CLONE_NEWIPC: > + if (ei->ns == tsk->nsproxy->ipc_ns) > + return 0; > + break; > + case CLONE_NEWNET: > + if (ei->ns == tsk->nsproxy->net_ns) > + return 0; > + break; > + case CLONE_NEWNS: > + if (ei->ns == tsk->nsproxy->mnt_ns) > + return 0; > + break; > + case CLONE_NEWPID: > + if (ei->ns == tsk->nsproxy->pid_ns_for_children) > + return 0; > + break; > + case CLONE_NEWUSER: > + if (ei->ns == current_user_ns()) > + return 0; > + break; > + case CLONE_NEWUTS: > + if (ei->ns == tsk->nsproxy->uts_ns) > + return 0; > + break; > + default: > + goto out; > + } > > new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs); > if (IS_ERR(new_nsproxy)) { > -- > 1.9.0 >
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