Merge tag 'v4.15-rc1' into patchwork

Linux 4.15-rc1

* tag 'v4.15-rc1': (12179 commits)
  Linux 4.15-rc1
  ARM: BUG if jumping to usermode address in kernel mode
  m68k/macboing: Fix missed timer callback assignment
  afs: remove redundant assignment of dvnode to itself
  afs: cell: Remove unnecessary code in afs_lookup_cell
  afs: Fix signal handling in some file ops
  afs: Fix some dentry handling in dir ops and missing key_puts
  afs: Make afs_write_begin() avoid writing to a page that's being stored
  sched/debug: Fix task state recording/printout
  x86/decoder: Add new TEST instruction pattern
  x86/PCI: Remove unused HyperTransport interrupt support
  x86/umip: Fix insn_get_code_seg_params()'s return value
  x86/boot/KASLR: Remove unused variable
  genirq/matrix: Make - vs ?: Precedence explicit
  irqchip/imgpdc: Use resource_size function on resource object
  irqchip/qcom: Fix u32 comparison with value less than zero
  ipvlan: Fix insufficient skb linear check for ipv6 icmp
  ipvlan: Fix insufficient skb linear check for arp
  geneve: only configure or fill UDP_ZERO_CSUM6_RX/TX info when CONFIG_IPV6
  net: dsa: bcm_sf2: Clear IDDQ_GLOBAL_PWR bit for PHY
  ...

1 files changed, 66 insertions, 10 deletions

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 1c19edf82427..cd50e99202b0 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);
@@ -798,15 +805,14 @@ EXPORT_SYMBOL_GPL(kthread_queue_work);
 /**
  * kthread_delayed_work_timer_fn - callback that queues the associated kthread
  *	delayed work when the timer expires.
- * @__data: pointer to the data associated with the timer
+ * @t: pointer to the expired timer
  *
  * The format of the function is defined by struct timer_list.
  * It should have been called from irqsafe timer with irq already off.
  */
-void kthread_delayed_work_timer_fn(unsigned long __data)
+void kthread_delayed_work_timer_fn(struct timer_list *t)
 {
-	struct kthread_delayed_work *dwork =
-		(struct kthread_delayed_work *)__data;
+	struct kthread_delayed_work *dwork = from_timer(dwork, t, timer);
 	struct kthread_work *work = &dwork->work;
 	struct kthread_worker *worker = work->worker;
 
@@ -837,8 +843,7 @@ void __kthread_queue_delayed_work(struct kthread_worker *worker,
 	struct timer_list *timer = &dwork->timer;
 	struct kthread_work *work = &dwork->work;
 
-	WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn ||
-		     timer->data != (unsigned long)dwork);
+	WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn);
 
 	/*
 	 * If @delay is 0, queue @dwork->work immediately.  This is for
@@ -1154,3 +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