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, 11 insertions, 2 deletions

diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 51bd91d911c3..6a4d82bedb03 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -49,6 +49,7 @@
 #include <linux/sched.h>
 #include <linux/ptrace.h>
 #include <linux/security.h>
+#include <linux/task_work.h>
 struct linux_binprm;
 
 /*
@@ -153,7 +154,6 @@ static inline void tracehook_signal_handler(int sig, siginfo_t *info,
 		ptrace_notify(SIGTRAP);
 }
 
-#ifdef TIF_NOTIFY_RESUME
 /**
  * set_notify_resume - cause tracehook_notify_resume() to be called
  * @task:		task that will call tracehook_notify_resume()
@@ -165,8 +165,10 @@ static inline void tracehook_signal_handler(int sig, siginfo_t *info,
  */
 static inline void set_notify_resume(struct task_struct *task)
 {
+#ifdef TIF_NOTIFY_RESUME
 	if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME))
 		kick_process(task);
+#endif
 }
 
 /**
@@ -184,7 +186,14 @@ static inline void set_notify_resume(struct task_struct *task)
  */
 static inline void tracehook_notify_resume(struct pt_regs *regs)
 {
+	/*
+	 * The caller just cleared TIF_NOTIFY_RESUME. This barrier
+	 * pairs with task_work_add()->set_notify_resume() after
+	 * hlist_add_head(task->task_works);
+	 */
+	smp_mb__after_clear_bit();
+	if (unlikely(!hlist_empty(&current->task_works)))
+		task_work_run();
 }
-#endif	/* TIF_NOTIFY_RESUME */
 
 #endif	/* <linux/tracehook.h> */