* Rename css_advance_task_iter() to css_task_iter_advance_css_set()
and make it clear it->task_pos too at the end of the iteration.
* Factor out css_task_iter_advance() from css_task_iter_next(). The
new function whines if called on a terminated iterator.
Except for the termination check, this is pure reorganization and
doesn't introduce any behavior changes. This will help the planned
locking update for css_task_iter.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
kernel/cgroup.c | 49 ++++++++++++++++++++++++++++---------------------
1 file changed, 28 insertions(+), 21 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 4e239e4..0a58445 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3791,12 +3791,12 @@ bool css_has_online_children(struct cgroup_subsys_state *css)
}
/**
- * css_advance_task_iter - advance a task itererator to the next css_set
+ * css_task_iter_advance_css_set - advance a task itererator to the next css_set
* @it: the iterator to advance
*
* Advance @it to the next css_set to walk.
*/
-static void css_advance_task_iter(struct css_task_iter *it)
+static void css_task_iter_advance_css_set(struct css_task_iter *it)
{
struct list_head *l = it->cset_pos;
struct cgrp_cset_link *link;
@@ -3807,6 +3807,7 @@ static void css_advance_task_iter(struct css_task_iter *it)
l = l->next;
if (l == it->cset_head) {
it->cset_pos = NULL;
+ it->task_pos = NULL;
return;
}
@@ -3830,6 +3831,28 @@ static void css_advance_task_iter(struct css_task_iter *it)
it->mg_tasks_head = &cset->mg_tasks;
}
+static void css_task_iter_advance(struct css_task_iter *it)
+{
+ struct list_head *l = it->task_pos;
+
+ WARN_ON_ONCE(!l);
+
+ /*
+ * Advance iterator to find next entry. cset->tasks is consumed
+ * first and then ->mg_tasks. After ->mg_tasks, we move onto the
+ * next cset.
+ */
+ l = l->next;
+
+ if (l == it->tasks_head)
+ l = it->mg_tasks_head->next;
+
+ if (l == it->mg_tasks_head)
+ css_task_iter_advance_css_set(it);
+ else
+ it->task_pos = l;
+}
+
/**
* css_task_iter_start - initiate task iteration
* @css: the css to walk tasks of
@@ -3862,7 +3885,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css,
it->cset_head = it->cset_pos;
- css_advance_task_iter(it);
+ css_task_iter_advance_css_set(it);
}
/**
@@ -3876,28 +3899,12 @@ void css_task_iter_start(struct cgroup_subsys_state *css,
struct task_struct *css_task_iter_next(struct css_task_iter *it)
{
struct task_struct *res;
- struct list_head *l = it->task_pos;
- /* If the iterator cg is NULL, we have no tasks */
if (!it->cset_pos)
return NULL;
- res = list_entry(l, struct task_struct, cg_list);
-
- /*
- * Advance iterator to find next entry. cset->tasks is consumed
- * first and then ->mg_tasks. After ->mg_tasks, we move onto the
- * next cset.
- */
- l = l->next;
-
- if (l == it->tasks_head)
- l = it->mg_tasks_head->next;
-
- if (l == it->mg_tasks_head)
- css_advance_task_iter(it);
- else
- it->task_pos = l;
+ res = list_entry(it->task_pos, struct task_struct, cg_list);
+ css_task_iter_advance(it);
return res;
}
--
2.4.3
--
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