Oleg Nesterov wrote:
On 07/26, Pavel Emelyanov wrote:
--- linux-2.6.23-rc1-mm1.orig/include/linux/pid.h 2007-07-26 16:34:45.000000000 +0400
+++ linux-2.6.23-rc1-mm1-7/include/linux/pid.h 2007-07-26 16:36:37.000000000 +0400
@@ -83,12 +92,34 @@ extern void FASTCALL(detach_pid(struct t
extern struct pid *alloc_pid(struct pid_namespace *ns);
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;
This looks a bit strange to me, but perhaps this is just matter of taste.
I think pid_nr(pid) should be pid_nr_ns(pid, current->nsproxy->pid_ns),
this is imho much closer to the current meaning. I won't persist though.
pid_nr, find_task_by_pid and all other stuff, that existed in the kernel
before the set are intended to work with global ids only (just as it was
before the set).
+pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)
+{
+ pid_t nr = 0;
+ if (pid && ns->level <= pid->level)
+ nr = pid->numbers[ns->level].nr;
+ return nr;
+}
I am not sure I understand the "ns->level <= pid->level" check. Isn't it
a bug to use a "wrong" namespace here? In that case BUG_ON() looks better.
Yes, that's a check for bad namespace passed.
If ns could be wrong, "ns->level <= pid->level" is not enough, we should
also check "pid->numbers[ns->level].ns == ns", no?
Yes, we should, and you're right in that we must have BUG_ON() here.
Oleg.
Thanks,
Pavel
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