[PATCH 13/19] introduce ptrace_set_syscall_trace()

[Oleg Nesterov]

No functional changes. Add the new helper, ptrace_set_syscall_trace(),
which should be used to set/clear TIF_SYSCALL_TRACE in ptrace code.
Currently it does nothing more.

Signed-off-by: Oleg Nesterov <oleg at redhat.com>
---
 kernel/ptrace.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 0b2aba5..b6fd922 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -37,6 +37,14 @@ static void ptrace_signal_wake_up(struct task_struct *p, int quiescent)
 		kick_process(p);
 }
 
+static void ptrace_set_syscall_trace(struct task_struct *p, bool on)
+{
+	if (on)
+		set_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
+	else
+		clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
+}
+
 /*
  * ptrace a task: make the debugger its new parent and
  * move it to the ptrace list.
@@ -364,7 +372,7 @@ static int ptrace_detach(struct task_struct *child, unsigned int data)
 
 	/* Architecture-specific hardware disable .. */
 	ptrace_disable(child);
-	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+	ptrace_set_syscall_trace(child, false);
 
 	write_lock_irq(&tasklist_lock);
 	/*
@@ -551,10 +559,7 @@ static int ptrace_resume(struct task_struct *child, long request,
 	if (!valid_signal(data))
 		return -EIO;
 
-	if (request == PTRACE_SYSCALL)
-		set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-	else
-		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+	ptrace_set_syscall_trace(child, request == PTRACE_SYSCALL);
 
 #ifdef TIF_SYSCALL_EMU
 	if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
-- 
1.5.5.1