taint: add explicit flag to show whether lock dep is still OK.

Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

kernel/panic.c

@@ -259,26 +259,19 @@ unsigned long get_taint(void)
 	return tainted_mask;
 }
 
-void add_taint(unsigned flag)
+/**
+ * add_taint: add a taint flag if not already set.
+ * @flag: one of the TAINT_* constants.
+ * @lockdep_ok: whether lock debugging is still OK.
+ *
+ * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
+ * some notewortht-but-not-corrupting cases, it can be set to true.
+ */
+void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
 {
-	/*
-	 * Can't trust the integrity of the kernel anymore.
-	 * We don't call directly debug_locks_off() because the issue
-	 * is not necessarily serious enough to set oops_in_progress to 1
-	 * Also we want to keep up lockdep for staging/out-of-tree
-	 * development and post-warning case.
-	 */
-	switch (flag) {
-	case TAINT_CRAP:
-	case TAINT_OOT_MODULE:
-	case TAINT_WARN:
-	case TAINT_FIRMWARE_WORKAROUND:
-		break;
-
-	default:
-		if (__debug_locks_off())
-			printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
-	}
+	if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
+		printk(KERN_WARNING
+		       "Disabling lock debugging due to kernel taint\n");
 
 	set_bit(flag, &tainted_mask);
 }
@@ -421,7 +414,8 @@ static void warn_slowpath_common(const char *file, int line, void *caller,
 	print_modules();
 	dump_stack();
 	print_oops_end_marker();
-	add_taint(taint);
+	/* Just a warning, don't kill lockdep. */
+	add_taint(taint, LOCKDEP_STILL_OK);
 }
 
 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)