signals: use HAVE_SET_RESTORE_SIGMASK

Change all the #ifdef TIF_RESTORE_SIGMASK conditionals in non-arch code to
#ifdef HAVE_SET_RESTORE_SIGMASK.  If arch code defines it first, the generic
set_restore_sigmask() using TIF_RESTORE_SIGMASK is not defined.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 9 insertions, 3 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index fe970cdca83c..86e60796db62 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1175,7 +1175,7 @@ struct task_struct {
         struct sighand_struct *sighand;
 
         sigset_t blocked, real_blocked;
-        sigset_t saved_sigmask;         /* To be restored with TIF_RESTORE_SIGMASK */
+        sigset_t saved_sigmask; /* restored if set_restore_sigmask() was used */
         struct sigpending pending;
 
         unsigned long sas_ss_sp;
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 81c5f82f0663..38a56477f27a 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -92,7 +92,13 @@ static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
 #define set_need_resched()      set_thread_flag(TIF_NEED_RESCHED)
 #define clear_need_resched()    clear_thread_flag(TIF_NEED_RESCHED)
 
-#ifdef TIF_RESTORE_SIGMASK
+#if defined TIF_RESTORE_SIGMASK && !defined HAVE_SET_RESTORE_SIGMASK
+/*
+ * An arch can define its own version of set_restore_sigmask() to get the
+ * job done however works, with or without TIF_RESTORE_SIGMASK.
+ */
+#define HAVE_SET_RESTORE_SIGMASK        1
+
 /**
  * set_restore_sigmask() - make sure saved_sigmask processing gets done
  *
@@ -109,7 +115,7 @@ static inline void set_restore_sigmask(void)
         set_thread_flag(TIF_RESTORE_SIGMASK);
         set_thread_flag(TIF_SIGPENDING);
 }
-#endif  /* TIF_RESTORE_SIGMASK */
+#endif  /* TIF_RESTORE_SIGMASK && !HAVE_SET_RESTORE_SIGMASK */
 
 #endif  /* __KERNEL__ */