[RFC PATCH 4/5] signal: Remove saved_sigmask

[Eric W. Biederman]

We have real_sigmask that serves the same purpose and is always kept
uptodate.  Remove a field from the task structure and a conditional
from the signal delivery code by removing this field.

Signed-off-by: "Eric W. Biederman" <ebied...@xmission.com>
---
 include/linux/sched.h        |  2 --
 include/linux/sched/signal.h |  9 +++------
 kernel/ptrace.c              | 12 ++----------
 kernel/signal.c              |  2 --
 4 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 11837410690f..520efbd355be 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -864,8 +864,6 @@ struct task_struct {
        struct sighand_struct           *sighand;
        sigset_t                        blocked;
        sigset_t                        real_blocked;
-       /* Restored if set_restore_sigmask() was used: */
-       sigset_t                        saved_sigmask;
        struct sigpending               pending;
        unsigned long                   sas_ss_sp;
        size_t                          sas_ss_size;
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 97f6a6a35a81..78678de45278 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -407,7 +407,7 @@ void task_join_group_stop(struct task_struct *task);
  */
 
 /**
- * set_restore_sigmask() - make sure saved_sigmask processing gets done
+ * set_restore_sigmask() - make sure real_sigmask processing gets done
  *
  * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
  * will run before returning to user mode, to process the flag.  For
@@ -479,7 +479,7 @@ static inline bool test_and_clear_restore_sigmask(void)
 static inline void restore_saved_sigmask(void)
 {
        if (test_and_clear_restore_sigmask())
-               __set_current_blocked(&current->saved_sigmask);
+               __set_current_blocked(&current->real_blocked);
 }
 
 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
@@ -494,10 +494,7 @@ static inline void restore_saved_sigmask_unless(bool 
interrupted)
 
 static inline sigset_t *sigmask_to_save(void)
 {
-       sigset_t *res = &current->blocked;
-       if (unlikely(test_restore_sigmask()))
-               res = &current->saved_sigmask;
-       return res;
+       return &current->real_blocked;
 }
 
 static inline int kill_cad_pid(int sig, int priv)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 6507d700d70f..5ed6126e1cc5 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -925,26 +925,18 @@ int ptrace_request(struct task_struct *child, long 
request,
                        ret = ptrace_setsiginfo(child, &siginfo);
                break;
 
-       case PTRACE_GETSIGMASK: {
-               sigset_t *mask;
-
+       case PTRACE_GETSIGMASK:
                if (addr != sizeof(sigset_t)) {
                        ret = -EINVAL;
                        break;
                }
 
-               if (test_tsk_restore_sigmask(child))
-                       mask = &child->saved_sigmask;
-               else
-                       mask = &child->blocked;
-
-               if (copy_to_user(datavp, mask, sizeof(sigset_t)))
+               if (copy_to_user(datavp, &child->real_blocked, 
sizeof(sigset_t)))
                        ret = -EFAULT;
                else
                        ret = 0;
 
                break;
-       }
 
        case PTRACE_SETSIGMASK: {
                sigset_t new_set;
diff --git a/kernel/signal.c b/kernel/signal.c
index fcd84f4a93c9..c37d4f209699 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2941,8 +2941,6 @@ EXPORT_SYMBOL(sigprocmask);
 static int set_sigmask(sigset_t *newset)
 {
        set_restore_sigmask();
-       current->saved_sigmask = current->blocked;
-
        sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
        __set_current_blocked(newset);
 
-- 
2.21.0.dirty