PM: sleep: Use two lines for "Restarting..." / "done" messages

Other messages are occasionally printed between these two, for example:

[203104.106534] Restarting tasks ...
[203104.106559] mei_hdcp 0000:00:16.0-b638ab7e-94e2-4ea2-a552-d1c54b627f04: bound 0000:00:02.0 (ops i915_hdcp_ops [i915])
[203104.112354] done.

This seems to be a timing issue, seen in two of the eleven
hibernation exits in my current `dmesg` output.

When printed on its own, the "done" message has the default log level.
This makes the output of `dmesg --level=warn` quite misleading.

Add enough context for the "done" messages to make sense on their own,
and use the same log level for all messages.

Change the messages to "<event>..." / "Done <event>.", unlike a449dfbfc089
which uses "<event>..." / "<event> completed.". Front-loading the unique
part of the message makes it easier to scan the log, and reduces ambiguity
for users who aren't confident in their English comprehension.

Reviewed-by: Lucas De Marchi <[e-mail]>
Signed-off-by: Andrew Sayers <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Rafael J. Wysocki <[e-mail]>

kernel/power/process.c

···
 
 	oom_killer_enable();
 
-	pr_info("Restarting tasks ... ");
+	pr_info("Restarting tasks ...\n");
 
 	__usermodehelper_set_disable_depth(UMH_FREEZING);
 	thaw_workqueues();
···
 	usermodehelper_enable();
 
 	schedule();
-	pr_cont("done.\n");
+	pr_info("Done restarting tasks.\n");
 	trace_suspend_resume(TPS("thaw_processes"), 0, false);
 }
 
···
 	struct task_struct *g, *p;
 
 	pm_nosig_freezing = false;
-	pr_info("Restarting kernel threads ... ");
+	pr_info("Restarting kernel threads ...\n");
 
 	thaw_workqueues();
 
···
 	read_unlock(&tasklist_lock);
 
 	schedule();
-	pr_cont("done.\n");
+	pr_info("Done restarting kernel threads.\n");
 }

tools/power/pm-graph/sleepgraph.py

···
 							'PM: early restore of devices complete after.*'],
 		'resume_complete': ['PM: resume of devices complete after.*',
 							'PM: restore of devices complete after.*'],
-		    'post_resume': [r'.*Restarting tasks \.\.\..*'],
+		    'post_resume': [r'.*Restarting tasks \.\.\..*',
+							'Done restarting tasks.*'],
 	}
 
 	# action table (expected events that occur and show up in dmesg)