pid namespaces: move alloc_pid() to copy_process()

Move alloc_pid() into copy_process().  This will keep all pid and pid
namespace code together and simplify error handling when we support multiple
pid namespaces.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 6 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index fd65bca38a93..2deaf481efab 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1040,6 +1040,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         if (p->binfmt && !try_module_get(p->binfmt->module))
                 goto bad_fork_cleanup_put_domain;
 
+        if (pid != &init_struct_pid) {
+                pid = alloc_pid();
+                if (!pid)
+                        goto bad_fork_put_binfmt_module;
+        }
+
         p->did_exec = 0;
         delayacct_tsk_init(p);  /* Must remain after dup_task_struct() */
         copy_flags(clone_flags, p);
@@ -1331,6 +1337,9 @@ bad_fork_cleanup_cgroup:
         cgroup_exit(p, cgroup_callbacks_done);
 bad_fork_cleanup_delays_binfmt:
         delayacct_tsk_free(p);
+        if (pid != &init_struct_pid)
+                free_pid(pid);
+bad_fork_put_binfmt_module:
         if (p->binfmt)
                 module_put(p->binfmt->module);
 bad_fork_cleanup_put_domain:
@@ -1395,19 +1404,16 @@ long do_fork(unsigned long clone_flags,
 {
         struct task_struct *p;
         int trace = 0;
-        struct pid *pid = alloc_pid();
         long nr;
 
-        if (!pid)
-                return -EAGAIN;
-        nr = pid->nr;
         if (unlikely(current->ptrace)) {
                 trace = fork_traceflag (clone_flags);
                 if (trace)
                         clone_flags |= CLONE_PTRACE;
         }
 
-        p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid);
+        p = copy_process(clone_flags, stack_start, regs, stack_size,
+                        parent_tidptr, child_tidptr, NULL);
         /*
          * Do this prior waking up the new thread - the thread pointer
          * might get invalid after that point, if the thread exits quickly.
@@ -1415,6 +1421,8 @@ long do_fork(unsigned long clone_flags,
         if (!IS_ERR(p)) {
                 struct completion vfork;
 
+                nr = pid_nr(task_pid(p));
+
                 if (clone_flags & CLONE_VFORK) {
                         p->vfork_done = &vfork;
                         init_completion(&vfork);
@@ -1448,7 +1456,6 @@ long do_fork(unsigned long clone_flags,
                         }
                 }
         } else {
-                free_pid(pid);
                 nr = PTR_ERR(p);
         }
         return nr;