proc: seqfile convert proc_pid_status to properly handle pid namespaces

Currently we possibly lookup the pid in the wrong pid namespace.  So
seq_file convert proc_pid_status which ensures the proper pid namespaces is
passed in.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: another build fix]
[akpm@linux-foundation.org: s390 build fix]
[akpm@linux-foundation.org: fix task_name() output]
[akpm@linux-foundation.org: fix nommu build]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andrew Morgan <morgan@kernel.org>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 67b2bfe..3e296ed 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2255,13 +2255,14 @@
 #endif /* CONFIG_PROC_PID_CPUSET */
 
 /* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
-char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
+void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
 {
-	buffer += sprintf(buffer, "Cpus_allowed:\t");
-	buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed);
-	buffer += sprintf(buffer, "\n");
-	buffer += sprintf(buffer, "Mems_allowed:\t");
-	buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed);
-	buffer += sprintf(buffer, "\n");
-	return buffer;
+	seq_printf(m, "Cpus_allowed:\t");
+	m->count += cpumask_scnprintf(m->buf + m->count, m->size - m->count,
+					task->cpus_allowed);
+	seq_printf(m, "\n");
+	seq_printf(m, "Mems_allowed:\t");
+	m->count += nodemask_scnprintf(m->buf + m->count, m->size - m->count,
+					task->mems_allowed);
+	seq_printf(m, "\n");
 }