PM / Sleep: Remove ftrace_stop/start() from suspend and hibernate

ftrace_stop() and ftrace_start() were added to the suspend and hibernate
process because there was some function within the work flow that caused
the system to reboot if it was traced. This function has recently been
found (restore_processor_state()). Now there's no reason to disable
function tracing while we are going into suspend or hibernate, which means
that being able to trace this will help tremendously in debugging any
issues with suspend or hibernate.

This also means that the ftrace_stop/start() functions can be removed
and simplify the function tracing code a bit.

Link: http://lkml.kernel.org/r/1518201.VD9cU33jRU@vostro.rjw.lan
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index fcc2611d3f145da1dcb32aa4814a2fa3b6fd6404..a9dfa79b6bab93f8cf62e24a0d3bd83c4d4534d5 100644 (file)
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -371,7 +371,6 @@ int hibernation_snapshot(int platform_mode)
        }
 
        suspend_console();
-       ftrace_stop();
        pm_restrict_gfp_mask();
 
        error = dpm_suspend(PMSG_FREEZE);
@@ -397,7 +396,6 @@ int hibernation_snapshot(int platform_mode)
        if (error || !in_suspend)
                pm_restore_gfp_mask();
 
-       ftrace_start();
        resume_console();
        dpm_complete(msg);
 
@@ -500,7 +498,6 @@ int hibernation_restore(int platform_mode)
 
        pm_prepare_console();
        suspend_console();
-       ftrace_stop();
        pm_restrict_gfp_mask();
        error = dpm_suspend_start(PMSG_QUIESCE);
        if (!error) {
@@ -508,7 +505,6 @@ int hibernation_restore(int platform_mode)
                dpm_resume_end(PMSG_RECOVER);
        }
        pm_restore_gfp_mask();
-       ftrace_start();
        resume_console();
        pm_restore_console();
        return error;
@@ -535,7 +531,6 @@ int hibernation_platform_enter(void)
 
        entering_platform_hibernation = true;
        suspend_console();
-       ftrace_stop();
        error = dpm_suspend_start(PMSG_HIBERNATE);
        if (error) {
                if (hibernation_ops->recover)
@@ -579,7 +574,6 @@ int hibernation_platform_enter(void)
  Resume_devices:
        entering_platform_hibernation = false;
        dpm_resume_end(PMSG_RESTORE);
-       ftrace_start();
        resume_console();
 
  Close:

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 4dd8822f732a2a23835fca1f8f9a991ca756c3dd..f6623da034d8b46505c58ac18b1203aaddfc5554 100644 (file)
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -248,7 +248,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
                goto Platform_wake;
        }
 
-       ftrace_stop();
        error = disable_nonboot_cpus();
        if (error || suspend_test(TEST_CPUS))
                goto Enable_cpus;
@@ -275,7 +274,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
 
  Enable_cpus:
        enable_nonboot_cpus();
-       ftrace_start();
 
  Platform_wake:
        if (need_suspend_ops(state) && suspend_ops->wake)