Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull second pile of signal handling patches from Al Viro:
 "This one is just task_work_add() series + remaining prereqs for it.

  There probably will be another pull request from that tree this
  cycle - at least for helpers, to get them out of the way for per-arch
  fixes remaining in the tree."

Fix trivial conflict in kernel/irq/manage.c: the merge of Andrew's pile
had brought in commit 97fd75b7b8e0 ("kernel/irq/manage.c: use the
pr_foo() infrastructure to prefix printks") which changed one of the
pr_err() calls that this merge moves around.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  keys: kill task_struct->replacement_session_keyring
  keys: kill the dummy key_replace_session_keyring()
  keys: change keyctl_session_to_parent() to use task_work_add()
  genirq: reimplement exit_irq_thread() hook via task_work_add()
  task_work_add: generic process-context callbacks
  avr32: missed _TIF_NOTIFY_RESUME on one of do_notify_resume callers
  parisc: need to check NOTIFY_RESUME when exiting from syscall
  move key_repace_session_keyring() into tracehook_notify_resume()
  TIF_NOTIFY_RESUME is defined on all targets now

1 files changed, 33 insertions, 35 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 7c475cd..ea0c6c2 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -16,6 +16,7 @@
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/task_work.h>
 
 #include "internals.h"
 
@@ -775,11 +776,39 @@ static void wake_threads_waitq(struct irq_desc *desc)
 		wake_up(&desc->wait_for_threads);
 }
 
+static void irq_thread_dtor(struct task_work *unused)
+{
+	struct task_struct *tsk = current;
+	struct irq_desc *desc;
+	struct irqaction *action;
+
+	if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
+		return;
+
+	action = kthread_data(tsk);
+
+	pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+	       tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
+
+
+	desc = irq_to_desc(action->irq);
+	/*
+	 * If IRQTF_RUNTHREAD is set, we need to decrement
+	 * desc->threads_active and wake possible waiters.
+	 */
+	if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+		wake_threads_waitq(desc);
+
+	/* Prevent a stale desc->threads_oneshot */
+	irq_finalize_oneshot(desc, action);
+}
+
 /*
  * Interrupt handler thread
  */
 static int irq_thread(void *data)
 {
+	struct task_work on_exit_work;
 	static const struct sched_param param = {
 		.sched_priority = MAX_USER_RT_PRIO/2,
 	};
@@ -795,7 +824,9 @@ static int irq_thread(void *data)
 		handler_fn = irq_thread_fn;
 
 	sched_setscheduler(current, SCHED_FIFO, &param);
-	current->irq_thread = 1;
+
+	init_task_work(&on_exit_work, irq_thread_dtor, NULL);
+	task_work_add(current, &on_exit_work, false);
 
 	while (!irq_wait_for_interrupt(action)) {
 		irqreturn_t action_ret;
@@ -817,44 +848,11 @@ static int irq_thread(void *data)
 	 * cannot touch the oneshot mask at this point anymore as
 	 * __setup_irq() might have given out currents thread_mask
 	 * again.
-	 *
-	 * Clear irq_thread. Otherwise exit_irq_thread() would make
-	 * fuzz about an active irq thread going into nirvana.
 	 */
-	current->irq_thread = 0;
+	task_work_cancel(current, irq_thread_dtor);
 	return 0;
 }
 
-/*
- * Called from do_exit()
- */
-void exit_irq_thread(void)
-{
-	struct task_struct *tsk = current;
-	struct irq_desc *desc;
-	struct irqaction *action;
-
-	if (!tsk->irq_thread)
-		return;
-
-	action = kthread_data(tsk);
-
-	pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
-	       tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
-
-	desc = irq_to_desc(action->irq);
-
-	/*
-	 * If IRQTF_RUNTHREAD is set, we need to decrement
-	 * desc->threads_active and wake possible waiters.
-	 */
-	if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
-		wake_threads_waitq(desc);
-
-	/* Prevent a stale desc->threads_oneshot */
-	irq_finalize_oneshot(desc, action);
-}
-
 static void irq_setup_forced_threading(struct irqaction *new)
 {
 	if (!force_irqthreads)