From b4f48b6363c81ca743ef46943ef23fd72e60f679 Mon Sep 17 00:00:00 2001
From: Paul Menage <menage@google.com>
Date: Thu, 18 Oct 2007 23:39:33 -0700
Subject: Task Control Groups: add fork()/exit() hooks

This adds the necessary hooks to the fork() and exit() paths to ensure
that new children inherit their parent's cgroup assignments, and that
exiting processes release reference counts on their cgroups.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/fork.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

(limited to 'kernel/fork.c')

diff --git a/kernel/fork.c b/kernel/fork.c
index 2ce28f165e3..e7c181454dc 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -30,6 +30,7 @@
 #include <linux/capability.h>
 #include <linux/cpu.h>
 #include <linux/cpuset.h>
+#include <linux/cgroup.h>
 #include <linux/security.h>
 #include <linux/swap.h>
 #include <linux/syscalls.h>
@@ -979,6 +980,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 {
 	int retval;
 	struct task_struct *p = NULL;
+	int cgroup_callbacks_done = 0;
 
 	if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
 		return ERR_PTR(-EINVAL);
@@ -1088,12 +1090,13 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	p->io_context = NULL;
 	p->audit_context = NULL;
 	cpuset_fork(p);
+	cgroup_fork(p);
 #ifdef CONFIG_NUMA
  	p->mempolicy = mpol_copy(p->mempolicy);
  	if (IS_ERR(p->mempolicy)) {
  		retval = PTR_ERR(p->mempolicy);
  		p->mempolicy = NULL;
- 		goto bad_fork_cleanup_cpuset;
+ 		goto bad_fork_cleanup_cgroup;
  	}
 	mpol_fix_fork_child_flag(p);
 #endif
@@ -1204,6 +1207,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	/* Perform scheduler related setup. Assign this task to a CPU. */
 	sched_fork(p, clone_flags);
 
+	/* Now that the task is set up, run cgroup callbacks if
+	 * necessary. We need to run them before the task is visible
+	 * on the tasklist. */
+	cgroup_fork_callbacks(p);
+	cgroup_callbacks_done = 1;
+
 	/* Need tasklist lock for parent etc handling! */
 	write_lock_irq(&tasklist_lock);
 
@@ -1318,9 +1327,10 @@ bad_fork_cleanup_security:
 bad_fork_cleanup_policy:
 #ifdef CONFIG_NUMA
 	mpol_free(p->mempolicy);
-bad_fork_cleanup_cpuset:
+bad_fork_cleanup_cgroup:
 #endif
 	cpuset_exit(p);
+	cgroup_exit(p, cgroup_callbacks_done);
 bad_fork_cleanup_delays_binfmt:
 	delayacct_tsk_free(p);
 	if (p->binfmt)
-- 
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