x86, do_signal: Simplify the TS_RESTORE_SIGMASK logic

1. do_signal() looks at TS_RESTORE_SIGMASK and calculates the
   mask which should be stored in the signal frame, then it
   passes "oldset" to the callees, down to setup_rt_frame().

   This is ugly, setup_rt_frame() can do this itself and nobody
   else needs this sigset_t. Move this code into setup_rt_frame.

2. do_signal() also clears TS_RESTORE_SIGMASK if handle_signal()
   succeeds.

   We can move this to setup_rt_frame() as well, this avoids the
   unnecessary checks and makes the logic more clear.

3. use set_current_blocked() instead of sigprocmask(SIG_SETMASK),
   sigprocmask() should be avoided.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20110710182203.GA27979@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 10 insertions, 19 deletions

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index bf9345da380b..8c55f97728cd 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -651,11 +651,15 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
 
 static int
 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
-               sigset_t *set, struct pt_regs *regs)
+                struct pt_regs *regs)
 {
         int usig = signr_convert(sig);
+        sigset_t *set = &current->blocked;
         int ret;
 
+        if (current_thread_info()->status & TS_RESTORE_SIGMASK)
+                set = &current->saved_sigmask;
+
         /* Set up the stack frame */
         if (is_ia32) {
                 if (ka->sa.sa_flags & SA_SIGINFO)
@@ -670,12 +674,13 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
                 return -EFAULT;
         }
 
+        current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
         return ret;
 }
 
 static int
 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
-              sigset_t *oldset, struct pt_regs *regs)
+                struct pt_regs *regs)
 {
         sigset_t blocked;
         int ret;
@@ -710,7 +715,7 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
                 regs->flags &= ~X86_EFLAGS_TF;
 
-        ret = setup_rt_frame(sig, ka, info, oldset, regs);
+        ret = setup_rt_frame(sig, ka, info, regs);
 
         if (ret)
                 return ret;
@@ -765,7 +770,6 @@ static void do_signal(struct pt_regs *regs)
         struct k_sigaction ka;
         siginfo_t info;
         int signr;
-        sigset_t *oldset;
 
         /*
          * We want the common case to go fast, which is why we may in certain
@@ -777,23 +781,10 @@ static void do_signal(struct pt_regs *regs)
         if (!user_mode(regs))
                 return;
 
-        if (current_thread_info()->status & TS_RESTORE_SIGMASK)
-                oldset = &current->saved_sigmask;
-        else
-                oldset = &current->blocked;
-
         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
         if (signr > 0) {
                 /* Whee! Actually deliver the signal.  */
-                if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
-                        /*
-                         * A signal was successfully delivered; the saved
-                         * sigmask will have been stored in the signal frame,
-                         * and will be restored by sigreturn, so we can simply
-                         * clear the TS_RESTORE_SIGMASK flag.
-                         */
-                        current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
-                }
+                handle_signal(signr, &info, &ka, regs);
                 return;
         }
 
@@ -821,7 +812,7 @@ static void do_signal(struct pt_regs *regs)
          */
         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
-                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+                set_current_blocked(&current->saved_sigmask);
         }
 }