This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / include / linux / nsproxy.h

diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
new file mode 100644 (file)
index 0000000..b3c2608
--- /dev/null
+++ b/include/linux/nsproxy.h
@@ -0,0 +1,61 @@
+#ifndef _LINUX_NSPROXY_H
+#define _LINUX_NSPROXY_H
+
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+
+struct mnt_namespace;
+struct uts_namespace;
+struct ipc_namespace;
+struct pid_namespace;
+
+/*
+ * A structure to contain pointers to all per-process
+ * namespaces - fs (mount), uts, network, sysvipc, etc.
+ *
+ * 'count' is the number of tasks holding a reference.
+ * The count for each namespace, then, will be the number
+ * of nsproxies pointing to it, not the number of tasks.
+ *
+ * The nsproxy is shared by tasks which share all namespaces.
+ * As soon as a single namespace is cloned or unshared, the
+ * nsproxy is copied.
+ */
+struct nsproxy {
+       atomic_t count;
+       spinlock_t nslock;
+       struct uts_namespace *uts_ns;
+       struct ipc_namespace *ipc_ns;
+       struct mnt_namespace *mnt_ns;
+       struct pid_namespace *pid_ns;
+};
+extern struct nsproxy init_nsproxy;
+
+struct nsproxy *dup_namespaces(struct nsproxy *orig);
+int copy_namespaces(int flags, struct task_struct *tsk);
+void get_task_namespaces(struct task_struct *tsk);
+void free_nsproxy(struct nsproxy *ns);
+
+static inline void get_nsproxy(struct nsproxy *ns)
+{
+       atomic_inc(&ns->count);
+}
+
+static inline void put_nsproxy(struct nsproxy *ns)
+{
+       if (atomic_dec_and_test(&ns->count)) {
+               free_nsproxy(ns);
+       }
+}
+
+static inline void exit_task_namespaces(struct task_struct *p)
+{
+       struct nsproxy *ns = p->nsproxy;
+       if (ns) {
+               task_lock(p);
+               p->nsproxy = NULL;
+               task_unlock(p);
+               put_nsproxy(ns);
+       }
+}
+#endif