[PATCH 5/5] [V2] Move alloc_pid() to copy_process()

[sukadev@us.ibm.com]

Subject: [PATCH 5/5] Move alloc_pid call to copy_process

From: Sukadev Bhattiprolu <sukadev@us.ibm.com>

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>
---
 kernel/fork.c |   19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

Index: lx26-22-rc6-mm1a/kernel/fork.c
===================================================================
--- lx26-22-rc6-mm1a.orig/kernel/fork.c	2007-07-16 12:55:13.000000000 -0700
+++ lx26-22-rc6-mm1a/kernel/fork.c	2007-07-17 10:08:12.000000000 -0700
@@ -1029,6 +1029,12 @@ static struct task_struct *copy_process(
 	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);
@@ -1316,6 +1322,9 @@ bad_fork_cleanup_container:
 #endif
 	container_exit(p, container_callbacks_done);
 	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:
@@ -1380,19 +1389,16 @@ 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.
@@ -1400,6 +1406,8 @@ 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);
@@ -1433,7 +1441,6 @@ long do_fork(unsigned long clone_flags,
 			}
 		}
 	} else {
-		free_pid(pid);
 		nr = PTR_ERR(p);
 	}
 	return nr;