Merge branch 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

* 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
  cgroup: fix to allow mounting a hierarchy by name
  cgroup: move assignement out of condition in cgroup_attach_proc()
  cgroup: Remove task_lock() from cgroup_post_fork()
  cgroup: add sparse annotation to cgroup_iter_start() and cgroup_iter_end()
  cgroup: mark cgroup_rmdir_waitq and cgroup_attach_proc() as static
  cgroup: only need to check oldcgrp==newgrp once
  cgroup: remove redundant get/put of task struct
  cgroup: remove redundant get/put of old css_set from migrate
  cgroup: Remove unnecessary task_lock before fetching css_set on migration
  cgroup: Drop task_lock(parent) on cgroup_fork()
  cgroups: remove redundant get/put of css_set from css_set_check_fetched()
  resource cgroups: remove bogus cast
  cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task()
  cgroup, cpuset: don't use ss->pre_attach()
  cgroup: don't use subsys->can_attach_task() or ->attach_task()
  cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach()
  cgroup: improve old cgroup handling in cgroup_attach_proc()
  cgroup: always lock threadgroup during migration
  threadgroup: extend threadgroup_lock() to cover exit and exec
  threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem
  ...

Fix up conflict in kernel/cgroup.c due to commit e0197aae59e5: "cgroups:
fix a css_set not found bug in cgroup_attach_proc" that already
mentioned that the bug is fixed (differently) in Tejun's cgroup
patchset. This one, in other words.

1 files changed, 48 insertions, 57 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 0b1712dba587..a09ac2b9a661 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1389,79 +1389,73 @@ static int fmeter_getrate(struct fmeter *fmp)
         return val;
 }
 
-/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
-static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
-                             struct task_struct *tsk)
-{
-        struct cpuset *cs = cgroup_cs(cont);
-
-        if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
-                return -ENOSPC;
-
-        /*
-         * Kthreads bound to specific cpus cannot be moved to a new cpuset; we
-         * cannot change their cpu affinity and isolating such threads by their
-         * set of allowed nodes is unnecessary.  Thus, cpusets are not
-         * applicable for such threads.  This prevents checking for success of
-         * set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may
-         * be changed.
-         */
-        if (tsk->flags & PF_THREAD_BOUND)
-                return -EINVAL;
-
-        return 0;
-}
-
-static int cpuset_can_attach_task(struct cgroup *cgrp, struct task_struct *task)
-{
-        return security_task_setscheduler(task);
-}
-
 /*
  * Protected by cgroup_lock. The nodemasks must be stored globally because
- * dynamically allocating them is not allowed in pre_attach, and they must
- * persist among pre_attach, attach_task, and attach.
+ * dynamically allocating them is not allowed in can_attach, and they must
+ * persist until attach.
  */
 static cpumask_var_t cpus_attach;
 static nodemask_t cpuset_attach_nodemask_from;
 static nodemask_t cpuset_attach_nodemask_to;
 
-/* Set-up work for before attaching each task. */
-static void cpuset_pre_attach(struct cgroup *cont)
+/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
+static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
+                             struct cgroup_taskset *tset)
 {
-        struct cpuset *cs = cgroup_cs(cont);
+        struct cpuset *cs = cgroup_cs(cgrp);
+        struct task_struct *task;
+        int ret;
+
+        if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
+                return -ENOSPC;
+
+        cgroup_taskset_for_each(task, cgrp, tset) {
+                /*
+                 * Kthreads bound to specific cpus cannot be moved to a new
+                 * cpuset; we cannot change their cpu affinity and
+                 * isolating such threads by their set of allowed nodes is
+                 * unnecessary.  Thus, cpusets are not applicable for such
+                 * threads.  This prevents checking for success of
+                 * set_cpus_allowed_ptr() on all attached tasks before
+                 * cpus_allowed may be changed.
+                 */
+                if (task->flags & PF_THREAD_BOUND)
+                        return -EINVAL;
+                if ((ret = security_task_setscheduler(task)))
+                        return ret;
+        }
 
+        /* prepare for attach */
         if (cs == &top_cpuset)
                 cpumask_copy(cpus_attach, cpu_possible_mask);
         else
                 guarantee_online_cpus(cs, cpus_attach);
 
         guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
-}
-
-/* Per-thread attachment work. */
-static void cpuset_attach_task(struct cgroup *cont, struct task_struct *tsk)
-{
-        int err;
-        struct cpuset *cs = cgroup_cs(cont);
 
-        /*
-         * can_attach beforehand should guarantee that this doesn't fail.
-         * TODO: have a better way to handle failure here
-         */
-        err = set_cpus_allowed_ptr(tsk, cpus_attach);
-        WARN_ON_ONCE(err);
-
-        cpuset_change_task_nodemask(tsk, &cpuset_attach_nodemask_to);
-        cpuset_update_task_spread_flag(cs, tsk);
+        return 0;
 }
 
-static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
-                          struct cgroup *oldcont, struct task_struct *tsk)
+static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
+                          struct cgroup_taskset *tset)
 {
         struct mm_struct *mm;
-        struct cpuset *cs = cgroup_cs(cont);
-        struct cpuset *oldcs = cgroup_cs(oldcont);
+        struct task_struct *task;
+        struct task_struct *leader = cgroup_taskset_first(tset);
+        struct cgroup *oldcgrp = cgroup_taskset_cur_cgroup(tset);
+        struct cpuset *cs = cgroup_cs(cgrp);
+        struct cpuset *oldcs = cgroup_cs(oldcgrp);
+
+        cgroup_taskset_for_each(task, cgrp, tset) {
+                /*
+                 * can_attach beforehand should guarantee that this doesn't
+                 * fail.  TODO: have a better way to handle failure here
+                 */
+                WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));
+
+                cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
+                cpuset_update_task_spread_flag(cs, task);
+        }
 
         /*
          * Change mm, possibly for multiple threads in a threadgroup. This is
@@ -1469,7 +1463,7 @@ static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
          */
         cpuset_attach_nodemask_from = oldcs->mems_allowed;
         cpuset_attach_nodemask_to = cs->mems_allowed;
-        mm = get_task_mm(tsk);
+        mm = get_task_mm(leader);
         if (mm) {
                 mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
                 if (is_memory_migrate(cs))
@@ -1925,9 +1919,6 @@ struct cgroup_subsys cpuset_subsys = {
         .create = cpuset_create,
         .destroy = cpuset_destroy,
         .can_attach = cpuset_can_attach,
-        .can_attach_task = cpuset_can_attach_task,
-        .pre_attach = cpuset_pre_attach,
-        .attach_task = cpuset_attach_task,
         .attach = cpuset_attach,
         .populate = cpuset_populate,
         .post_clone = cpuset_post_clone,