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authorOleg Nesterov <oleg@redhat.com>2012-08-26 21:12:17 +0200
committerIngo Molnar <mingo@kernel.org>2012-09-13 16:47:37 +0200
commitf784e8a7989c0da3062d04bfea3db90f41e8f738 (patch)
tree40ec8dac81ab8bd5f23b1c440c30737d7acad6c9 /kernel/signal.c
parentb3f68f16dbcde6fcdf0fd27695391ff7e9d41233 (diff)
downloadvexpress-lsk-f784e8a7989c0da3062d04bfea3db90f41e8f738.tar.gz
task_work: Simplify the usage in ptrace_notify() and get_signal_to_deliver()
ptrace_notify() and get_signal_to_deliver() do unnecessary things before task_work_run(): 1. smp_mb__after_clear_bit() is not needed, test_and_clear_bit() implies mb(). 2. And we do not need the barrier at all, in this case we only care about the "synchronous" works added by the task itself. 3. No need to clear TIF_NOTIFY_RESUME, and we should not assume task_works is the only user of this flag. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120826191217.GA4238@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c18
1 files changed, 4 insertions, 14 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index be4f856d52f..2c681f11b7d 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1971,13 +1971,8 @@ static void ptrace_do_notify(int signr, int exit_code, int why)
void ptrace_notify(int exit_code)
{
BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
- if (unlikely(current->task_works)) {
- if (test_and_clear_ti_thread_flag(current_thread_info(),
- TIF_NOTIFY_RESUME)) {
- smp_mb__after_clear_bit();
- task_work_run();
- }
- }
+ if (unlikely(current->task_works))
+ task_work_run();
spin_lock_irq(&current->sighand->siglock);
ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
@@ -2198,13 +2193,8 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
struct signal_struct *signal = current->signal;
int signr;
- if (unlikely(current->task_works)) {
- if (test_and_clear_ti_thread_flag(current_thread_info(),
- TIF_NOTIFY_RESUME)) {
- smp_mb__after_clear_bit();
- task_work_run();
- }
- }
+ if (unlikely(current->task_works))
+ task_work_run();
if (unlikely(uprobe_deny_signal()))
return 0;