Merge ../linus

1 files changed, 57 insertions, 0 deletions

diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
new file mode 100644
index 000000000000..fdfb0e44912f
--- /dev/null
+++ b/include/linux/nsproxy.h
@@ -0,0 +1,57 @@
+#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;
+	unsigned long id;
+	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 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