[Devel] [PATCH 09/17] Pid-NS(V3) Use pid ns from pid->upid_list
sukadev at us.ibm.com
sukadev at us.ibm.com
Sat Jun 16 16:01:50 PDT 2007
Subject: [PATCH 09/17] Pid-NS(V3) Use pid ns from pid->upid_list
From: Sukadev Bhattiprolu <sukadev at us.ibm.com>
We drop a process's refernces to other namespaces during the process exit.
But we must hold a reference to pid namespace until the task is reaped.
For instance, we flush the procfs dentries of the process only in
release_task(), long after dropping references to other namespaces.
So we decouple 'nxproxy' from the 'pid_namespace' allowing us to free
them independently.
With multiple pid namespaces, a process can have different pid_t values in
different pid namespaces and 'struct upid' and the pid->upid_list list
provide this association of pid_t value with pid namespace for a process.
Use pid->upid_list list to find the active pid namespace of a process and
remove nsproxy->pid_namespace.
TODO:
- Include pid_namespace in pid_hash() so processes with same pid_t
in different namespaces are on different hash lists.
Changelog:
2.6.21-mm2-pidns3:
- 'struct upid' used to be called 'struct pid_nr' and a list of these
were hanging off of 'struct pid'. So, we renamed 'struct pid_nr'
and now hold them in a statically sized array in 'struct pid' since
the number of 'struct upid's for a process is known at process-
creation time.
[2.6.21-rc3-mm2]
- Drop support for unshare() of pid namespace which simplifies cloning
of pid namespace and reorganize several functions.
Signed-off-by: Sukadev Bhattiprolu <sukadev at us.ibm.com>
---
include/linux/init_task.h | 1 -
include/linux/nsproxy.h | 2 --
include/linux/pid.h | 19 +++++++++++++++++++
include/linux/pid_namespace.h | 6 +++---
kernel/nsproxy.c | 10 ----------
kernel/pid.c | 7 -------
6 files changed, 22 insertions(+), 23 deletions(-)
Index: lx26-22-rc4-mm2/include/linux/init_task.h
===================================================================
--- lx26-22-rc4-mm2.orig/include/linux/init_task.h 2007-06-15 19:47:58.000000000 -0700
+++ lx26-22-rc4-mm2/include/linux/init_task.h 2007-06-15 19:48:22.000000000 -0700
@@ -72,7 +72,6 @@
extern struct nsproxy init_nsproxy;
#define INIT_NSPROXY(nsproxy) { \
- .pid_ns = &init_pid_ns, \
.count = ATOMIC_INIT(1), \
.nslock = __SPIN_LOCK_UNLOCKED(nsproxy.nslock), \
.uts_ns = &init_uts_ns, \
Index: lx26-22-rc4-mm2/include/linux/nsproxy.h
===================================================================
--- lx26-22-rc4-mm2.orig/include/linux/nsproxy.h 2007-06-15 19:47:58.000000000 -0700
+++ lx26-22-rc4-mm2/include/linux/nsproxy.h 2007-06-15 19:48:22.000000000 -0700
@@ -7,7 +7,6 @@
struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
-struct pid_namespace;
/*
* A structure to contain pointers to all per-process
@@ -27,7 +26,6 @@ struct nsproxy {
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;
Index: lx26-22-rc4-mm2/include/linux/pid_namespace.h
===================================================================
--- lx26-22-rc4-mm2.orig/include/linux/pid_namespace.h 2007-06-15 19:47:58.000000000 -0700
+++ lx26-22-rc4-mm2/include/linux/pid_namespace.h 2007-06-16 02:08:32.000000000 -0700
@@ -42,7 +42,6 @@ static inline struct pid_namespace *get_
return ns;
}
-extern struct pid_namespace *copy_pid_ns(int flags, struct pid_namespace *ns);
extern void free_pid_ns(struct kref *kref);
static inline void put_pid_ns(struct pid_namespace *ns)
@@ -50,14 +49,15 @@ static inline void put_pid_ns(struct pid
kref_put(&ns->kref, free_pid_ns);
}
+extern struct pid_namespace *pid_active_pid_ns(struct pid *pid);
static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
{
- return tsk->nsproxy->pid_ns;
+ return pid_active_pid_ns(task_pid(tsk));
}
static inline struct task_struct *task_child_reaper(struct task_struct *tsk)
{
- return init_pid_ns.child_reaper;
+ return task_active_pid_ns(tsk)->child_reaper;
}
#endif /* _LINUX_PID_NS_H */
Index: lx26-22-rc4-mm2/kernel/nsproxy.c
===================================================================
--- lx26-22-rc4-mm2.orig/kernel/nsproxy.c 2007-06-15 19:47:58.000000000 -0700
+++ lx26-22-rc4-mm2/kernel/nsproxy.c 2007-06-16 02:08:32.000000000 -0700
@@ -19,7 +19,6 @@
#include <linux/init_task.h>
#include <linux/mnt_namespace.h>
#include <linux/utsname.h>
-#include <linux/pid_namespace.h>
struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
@@ -75,15 +74,8 @@ static struct nsproxy *create_new_namesp
if (IS_ERR(new_nsp->ipc_ns))
goto out_ipc;
- new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
- if (IS_ERR(new_nsp->pid_ns))
- goto out_pid;
-
return new_nsp;
-out_pid:
- if (new_nsp->ipc_ns)
- put_ipc_ns(new_nsp->ipc_ns);
out_ipc:
if (new_nsp->uts_ns)
put_uts_ns(new_nsp->uts_ns);
@@ -138,8 +130,6 @@ void free_nsproxy(struct nsproxy *ns)
put_uts_ns(ns->uts_ns);
if (ns->ipc_ns)
put_ipc_ns(ns->ipc_ns);
- if (ns->pid_ns)
- put_pid_ns(ns->pid_ns);
kfree(ns);
}
Index: lx26-22-rc4-mm2/kernel/pid.c
===================================================================
--- lx26-22-rc4-mm2.orig/kernel/pid.c 2007-06-15 19:48:11.000000000 -0700
+++ lx26-22-rc4-mm2/kernel/pid.c 2007-06-16 02:08:32.000000000 -0700
@@ -461,13 +461,6 @@ struct pid *find_ge_pid(int nr)
}
EXPORT_SYMBOL_GPL(find_get_pid);
-struct pid_namespace *copy_pid_ns(int flags, struct pid_namespace *old_ns)
-{
- BUG_ON(!old_ns);
- get_pid_ns(old_ns);
- return old_ns;
-}
-
void free_pid_ns(struct kref *kref)
{
struct pid_namespace *ns;
Index: lx26-22-rc4-mm2/include/linux/pid.h
===================================================================
--- lx26-22-rc4-mm2.orig/include/linux/pid.h 2007-06-15 19:47:58.000000000 -0700
+++ lx26-22-rc4-mm2/include/linux/pid.h 2007-06-16 02:08:32.000000000 -0700
@@ -133,6 +133,25 @@ extern pid_t pid_to_nr(struct pid *pid);
#define while_each_pid_task(pid, type, task) \
} \
} while (0)
+/*
+ * Return the active upid of the process @pid.
+ *
+ * Note: At present, there is only one upid corresponding to init_pid_ns.
+ */
+static inline struct upid *pid_active_upid(struct pid *pid)
+{
+ return &pid->upid_list[0];
+}
+
+/*
+ * Return the active pid namespace of the process @pid.
+ *
+ * Note: At present, there is only one pid namespace (init_pid_ns).
+ */
+static inline struct pid_namespace *pid_active_pid_ns(struct pid *pid)
+{
+ return pid_active_upid(pid)->pid_ns;
+}
/*
* Return the pid_t by which the process @pid is known in the pid
--
_______________________________________________
Containers mailing list
Containers at lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/containers
More information about the Devel
mailing list