Merge branch 'for-2.6.27' of git://linux-nfs.org/~bfields/linux

[pandora-kernel.git] / include / linux / pid.h

diff --git a/include/linux/pid.h b/include/linux/pid.h
index 1e0e4e3..c21c7e8 100644 (file)
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -40,15 +40,28 @@ enum pid_type
  * processes.
  */
 
-struct pid
-{
-       atomic_t count;
+
+/*
+ * struct upid is used to get the id of the struct pid, as it is
+ * seen in particular namespace. Later the struct pid is found with
+ * find_pid_ns() using the int nr and struct pid_namespace *ns.
+ */
+
+struct upid {
        /* Try to keep pid_chain in the same cacheline as nr for find_pid */
        int nr;
+       struct pid_namespace *ns;
        struct hlist_node pid_chain;
+};
+
+struct pid
+{
+       atomic_t count;
        /* lists of tasks that use this pid */
        struct hlist_head tasks[PIDTYPE_MAX];
        struct rcu_head rcu;
+       unsigned int level;
+       struct upid numbers[1];
 };
 
 extern struct pid init_struct_pid;
@@ -66,10 +79,9 @@ static inline struct pid *get_pid(struct pid *pid)
        return pid;
 }
 
-extern void FASTCALL(put_pid(struct pid *pid));
-extern struct task_struct *FASTCALL(pid_task(struct pid *pid, enum pid_type));
-extern struct task_struct *FASTCALL(get_pid_task(struct pid *pid,
-                                               enum pid_type));
+extern void put_pid(struct pid *pid);
+extern struct task_struct *pid_task(struct pid *pid, enum pid_type);
+extern struct task_struct *get_pid_task(struct pid *pid, enum pid_type);
 
 extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type);
 
@@ -77,35 +89,63 @@ extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type);
  * attach_pid() and detach_pid() must be called with the tasklist_lock
  * write-held.
  */
-extern int FASTCALL(attach_pid(struct task_struct *task,
-                               enum pid_type type, struct pid *pid));
-extern void FASTCALL(detach_pid(struct task_struct *task, enum pid_type));
-extern void FASTCALL(transfer_pid(struct task_struct *old,
-                                 struct task_struct *new, enum pid_type));
+extern void attach_pid(struct task_struct *task, enum pid_type type,
+                       struct pid *pid);
+extern void detach_pid(struct task_struct *task, enum pid_type);
+extern void change_pid(struct task_struct *task, enum pid_type,
+                       struct pid *pid);
+extern void transfer_pid(struct task_struct *old, struct task_struct *new,
+                        enum pid_type);
+
+struct pid_namespace;
+extern struct pid_namespace init_pid_ns;
 
 /*
  * look up a PID in the hash table. Must be called with the tasklist_lock
  * or rcu_read_lock() held.
+ *
+ * find_pid_ns() finds the pid in the namespace specified
+ * find_pid() find the pid by its global id, i.e. in the init namespace
+ * find_vpid() finr the pid by its virtual id, i.e. in the current namespace
+ *
+ * see also find_task_by_pid() set in include/linux/sched.h
  */
-extern struct pid *FASTCALL(find_pid(int nr));
+extern struct pid *find_pid_ns(int nr, struct pid_namespace *ns);
+extern struct pid *find_vpid(int nr);
+extern struct pid *find_pid(int nr);
 
 /*
  * Lookup a PID in the hash table, and return with it's count elevated.
  */
 extern struct pid *find_get_pid(int nr);
-extern struct pid *find_ge_pid(int nr);
+extern struct pid *find_ge_pid(int nr, struct pid_namespace *);
+int next_pidmap(struct pid_namespace *pid_ns, int last);
+
+extern struct pid *alloc_pid(struct pid_namespace *ns);
+extern void free_pid(struct pid *pid);
 
-extern struct pid *alloc_pid(void);
-extern void FASTCALL(free_pid(struct pid *pid));
+/*
+ * the helpers to get the pid's id seen from different namespaces
+ *
+ * pid_nr()    : global id, i.e. the id seen from the init namespace;
+ * pid_vnr()   : virtual id, i.e. the id seen from the pid namespace of
+ *               current.
+ * pid_nr_ns() : id seen from the ns specified.
+ *
+ * see also task_xid_nr() etc in include/linux/sched.h
+ */
 
 static inline pid_t pid_nr(struct pid *pid)
 {
        pid_t nr = 0;
        if (pid)
-               nr = pid->nr;
+               nr = pid->numbers[0].nr;
        return nr;
 }
 
+pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns);
+pid_t pid_vnr(struct pid *pid);
+
 #define do_each_pid_task(pid, type, task)                              \
        do {                                                            \
                struct hlist_node *pos___;                              \
@@ -113,7 +153,13 @@ static inline pid_t pid_nr(struct pid *pid)
                        hlist_for_each_entry_rcu((task), pos___,        \
                                &pid->tasks[type], pids[type].node) {
 
+                       /*
+                        * Both old and new leaders may be attached to
+                        * the same pid in the middle of de_thread().
+                        */
 #define while_each_pid_task(pid, type, task)                           \
+                               if (type == PIDTYPE_PID)                \
+                                       break;                          \
                        }                                               \
        } while (0)