[tip:x86/signal] x86, do_signal: Simplify the TS_RESTORE_SIGMASK logic

From: tip-bot for Oleg Nesterov
Date: Fri Jul 15 2011 - 01:47:33 EST


Commit-ID: 9b429620740945363b746414e8b9a84b8119914c
Gitweb: http://git.kernel.org/tip/9b429620740945363b746414e8b9a84b8119914c
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Sun, 10 Jul 2011 20:22:03 +0200
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Thu, 14 Jul 2011 21:22:11 -0700

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@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20110710182203.GA27979@xxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/signal.c | 29 ++++++++++-------------------
1 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index bf9345d..8c55f97 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);
}
}

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/