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-rw-r--r--kernel/kthread.c66
1 files changed, 62 insertions, 4 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index ba3992c8c375..8af313081b0d 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -20,7 +20,6 @@
#include <linux/freezer.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
-#include <linux/cgroup.h>
#include <trace/events/sched.h>
static DEFINE_SPINLOCK(kthread_create_lock);
@@ -47,6 +46,9 @@ struct kthread {
void *data;
struct completion parked;
struct completion exited;
+#ifdef CONFIG_BLK_CGROUP
+ struct cgroup_subsys_state *blkcg_css;
+#endif
};
enum KTHREAD_BITS {
@@ -74,11 +76,17 @@ static inline struct kthread *to_kthread(struct task_struct *k)
void free_kthread_struct(struct task_struct *k)
{
+ struct kthread *kthread;
+
/*
* Can be NULL if this kthread was created by kernel_thread()
* or if kmalloc() in kthread() failed.
*/
- kfree(to_kthread(k));
+ kthread = to_kthread(k);
+#ifdef CONFIG_BLK_CGROUP
+ WARN_ON_ONCE(kthread && kthread->blkcg_css);
+#endif
+ kfree(kthread);
}
/**
@@ -196,7 +204,7 @@ static int kthread(void *_create)
struct kthread *self;
int ret;
- self = kmalloc(sizeof(*self), GFP_KERNEL);
+ self = kzalloc(sizeof(*self), GFP_KERNEL);
set_kthread_struct(self);
/* If user was SIGKILLed, I release the structure. */
@@ -212,7 +220,6 @@ static int kthread(void *_create)
do_exit(-ENOMEM);
}
- self->flags = 0;
self->data = data;
init_completion(&self->exited);
init_completion(&self->parked);
@@ -1152,3 +1159,54 @@ void kthread_destroy_worker(struct kthread_worker *worker)
kfree(worker);
}
EXPORT_SYMBOL(kthread_destroy_worker);
+
+#ifdef CONFIG_BLK_CGROUP
+/**
+ * kthread_associate_blkcg - associate blkcg to current kthread
+ * @css: the cgroup info
+ *
+ * Current thread must be a kthread. The thread is running jobs on behalf of
+ * other threads. In some cases, we expect the jobs attach cgroup info of
+ * original threads instead of that of current thread. This function stores
+ * original thread's cgroup info in current kthread context for later
+ * retrieval.
+ */
+void kthread_associate_blkcg(struct cgroup_subsys_state *css)
+{
+ struct kthread *kthread;
+
+ if (!(current->flags & PF_KTHREAD))
+ return;
+ kthread = to_kthread(current);
+ if (!kthread)
+ return;
+
+ if (kthread->blkcg_css) {
+ css_put(kthread->blkcg_css);
+ kthread->blkcg_css = NULL;
+ }
+ if (css) {
+ css_get(css);
+ kthread->blkcg_css = css;
+ }
+}
+EXPORT_SYMBOL(kthread_associate_blkcg);
+
+/**
+ * kthread_blkcg - get associated blkcg css of current kthread
+ *
+ * Current thread must be a kthread.
+ */
+struct cgroup_subsys_state *kthread_blkcg(void)
+{
+ struct kthread *kthread;
+
+ if (current->flags & PF_KTHREAD) {
+ kthread = to_kthread(current);
+ if (kthread)
+ return kthread->blkcg_css;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(kthread_blkcg);
+#endif