[RFC][v4][PATCH 4/7]: Add target_pids parameter to alloc_pid()

Sukadev Bhattiprolu
2009-08-07T06:13:07Z

Subject: [RFC][v4][PATCH 4/7]: Add target_pids parameter to alloc_pid()

This parameter is currently NULL, but will be used in a follow-on patch.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Reviewed-by: Oren Laadan <orenl@cs.columbia.edu>
---
include/linux/pid.h | 2 +-
kernel/fork.c | 3 ++-
kernel/pid.c | 9 +++++++--
3 files changed, 10 insertions(+), 4 deletions(-)

Index: linux-2.6/include/linux/pid.h
===================================================================
--- linux-2.6.orig/include/linux/pid.h 2009-08-05 19:34:37.000000000 -0700
+++ linux-2.6/include/linux/pid.h 2009-08-05 19:35:08.000000000 -0700
@@ -119,7 +119,7 @@
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 struct pid *alloc_pid(struct pid_namespace *ns, pid_t *target_pids);
extern void free_pid(struct pid *pid);

/*
Index: linux-2.6/kernel/fork.c
===================================================================
--- linux-2.6.orig/kernel/fork.c 2009-08-05 19:34:37.000000000 -0700
+++ linux-2.6/kernel/fork.c 2009-08-05 19:35:08.000000000 -0700
@@ -954,6 +954,7 @@
int retval;
struct task_struct *p;
int cgroup_callbacks_done = 0;
+ pid_t *target_pids = NULL;

if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
return ERR_PTR(-EINVAL);
@@ -1124,7 +1125,7 @@
goto bad_fork_cleanup_io;

if (pid != &init_struct_pid) {
- pid = alloc_pid(p->nsproxy->pid_ns);
+ pid = alloc_pid(p->nsproxy->pid_ns, target_pids);
if (IS_ERR(pid)) {
retval = PTR_ERR(pid);
goto bad_fork_cleanup_io;
Index: linux-2.6/kernel/pid.c
===================================================================
--- linux-2.6.orig/kernel/pid.c 2009-08-05 19:34:37.000000000 -0700
+++ linux-2.6/kernel/pid.c 2009-08-05 19:35:08.000000000 -0700
@@ -280,13 +280,14 @@
call_rcu(&pid->rcu, delayed_put_pid);
}

-struct pid *alloc_pid(struct pid_namespace *ns)
+struct pid *alloc_pid(struct pid_namespace *ns, pid_t *target_pids)
{
struct pid *pid;
enum pid_type type;
int i, nr;
struct pid_namespace *tmp;
struct upid *upid;
+ int tpid;

pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL);
if (!pid)
@@ -294,7 +295,11 @@

tmp = ns;
for (i = ns->level; i >= 0; i--) {
- nr = alloc_pidmap(tmp, 0);
+ tpid = 0;
+ if (target_pids)
+ tpid = target_pids[i];
+
+ nr = alloc_pidmap(tmp, tpid);
if (nr < 0)
goto out_free;