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 7c475cd3f6e6..ea0c6c2ae6f7 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)