Merge tag 'v3.6-rc1' into staging/for_v3.6

Linux 3.6-rc1

* tag 'v3.6-rc1': (18733 commits)
  Linux 3.6-rc1
  mm: remove node_start_pfn checking in new WARN_ON for now
  ARM: mmp: add missing irqs.h
  arm: mvebu: fix typo in .dtsi comment for Armada XP SoCs
  ARM: PRIMA2: delete redundant codes to restore LATCHED when timer resumes
  libceph: fix crypto key null deref, memory leak
  ceph: simplify+fix atomic_open
  sh: explicitly include sh_dma.h in setup-sh7722.c
  um: Add arch/x86/um to MAINTAINERS
  um: pass siginfo to guest process
  um: fix ubd_file_size for read-only files
  md/dm-raid: DM_RAID should select MD_RAID10
  md/raid1: submit IO from originating thread instead of md thread.
  raid5: raid5d handle stripe in batch way
  raid5: make_request use batch stripe release
  um: pull interrupt_end() into userspace()
  um: split syscall_trace(), pass pt_regs to it
  um: switch UPT_SET_RETURN_VALUE and regs_return_value to pt_regs
  MIPS: Loongson 2: Sort out clock managment.
  locks: remove unused lm_release_private
  ...

1 files changed, 80 insertions, 0 deletions

diff --git a/kernel/task_work.c b/kernel/task_work.c
new file mode 100644
index 000000000000..91d4e1742a0c
--- /dev/null
+++ b/kernel/task_work.c
@@ -0,0 +1,80 @@
+#include <linux/spinlock.h>
+#include <linux/task_work.h>
+#include <linux/tracehook.h>
+
+int
+task_work_add(struct task_struct *task, struct callback_head *twork, bool notify)
+{
+	struct callback_head *last, *first;
+	unsigned long flags;
+
+	/*
+	 * Not inserting the new work if the task has already passed
+	 * exit_task_work() is the responisbility of callers.
+	 */
+	raw_spin_lock_irqsave(&task->pi_lock, flags);
+	last = task->task_works;
+	first = last ? last->next : twork;
+	twork->next = first;
+	if (last)
+		last->next = twork;
+	task->task_works = twork;
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+	/* test_and_set_bit() implies mb(), see tracehook_notify_resume(). */
+	if (notify)
+		set_notify_resume(task);
+	return 0;
+}
+
+struct callback_head *
+task_work_cancel(struct task_struct *task, task_work_func_t func)
+{
+	unsigned long flags;
+	struct callback_head *last, *res = NULL;
+
+	raw_spin_lock_irqsave(&task->pi_lock, flags);
+	last = task->task_works;
+	if (last) {
+		struct callback_head *q = last, *p = q->next;
+		while (1) {
+			if (p->func == func) {
+				q->next = p->next;
+				if (p == last)
+					task->task_works = q == p ? NULL : q;
+				res = p;
+				break;
+			}
+			if (p == last)
+				break;
+			q = p;
+			p = q->next;
+		}
+	}
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+	return res;
+}
+
+void task_work_run(void)
+{
+	struct task_struct *task = current;
+	struct callback_head *p, *q;
+
+	while (1) {
+		raw_spin_lock_irq(&task->pi_lock);
+		p = task->task_works;
+		task->task_works = NULL;
+		raw_spin_unlock_irq(&task->pi_lock);
+
+		if (unlikely(!p))
+			return;
+
+		q = p->next; /* head */
+		p->next = NULL; /* cut it */
+		while (q) {
+			p = q->next;
+			q->func(q);
+			q = p;
+		}
+	}
+}