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Subject[PATCH] 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>
---

arch/x86/kernel/signal.c | 29 ++++++++++-------------------
1 file changed, 10 insertions(+), 19 deletions(-)

--- ptrace/arch/x86/kernel/signal.c~2_restore_sigmask 2011-07-10 18:06:30.000000000 +0200
+++ ptrace/arch/x86/kernel/signal.c 2011-07-10 19:45:21.000000000 +0200
@@ -653,11 +653,15 @@ int ia32_setup_frame(int sig, struct k_s

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)
@@ -672,12 +676,13 @@ setup_rt_frame(int sig, struct k_sigacti
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;
@@ -712,7 +717,7 @@ handle_signal(unsigned long sig, siginfo
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;
@@ -758,7 +763,6 @@ static void do_signal(struct pt_regs *re
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
@@ -770,23 +774,10 @@ static void do_signal(struct pt_regs *re
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;
}

@@ -814,7 +805,7 @@ static void do_signal(struct pt_regs *re
*/
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);
}
}



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