er_xor_blocks(void)
-{
-	active_template = XOR_SELECT_TEMPLATE(NULL);
-
-	if (!active_template) {
-#define xor_speed	do_xor_register
-		// register all the templates and pick the first as the default
-		XOR_TRY_TEMPLATES;
-#undef xor_speed
-		active_template = template_list;
-	}
-	return 0;
-}
-#endif
-
 #define BENCH_SIZE	4096
 #define REPS		800U
 
@@ -85,9 +70,6 @@ do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
 	unsigned long reps;
 	ktime_t min, start, t0;
 
-	tmpl->next = template_list;
-	template_list = tmpl;
-
 	preempt_disable();
 
 	reps = 0;
@@ -111,63 +93,79 @@ do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
 	pr_info("   %-16s: %5d MB/sec\n", tmpl->name, speed);
 }
 
-static int __init
-calibrate_xor_blocks(void)
+static int __init calibrate_xor_blocks(void)
 {
 	void *b1, *b2;
 	struct xor_block_template *f, *fastest;
 
-	fastest = XOR_SELECT_TEMPLATE(NULL);
-
-	if (fastest) {
-		printk(KERN_INFO "xor: automatically using best "
-				 "checksumming function   %-10s\n",
-		       fastest->name);
-		goto out;
-	}
+	if (xor_forced)
+		return 0;
 
 	b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
 	if (!b1) {
-		printk(KERN_WARNING "xor: Yikes!  No memory available.\n");
+		pr_info("xor: Yikes!  No memory available.\n");
 		return -ENOMEM;
 	}
 	b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
 
-	/*
-	 * If this arch/cpu has a short-circuited selection, don't loop through
-	 * all the possible functions, just test the best one
-	 */
-
-#define xor_speed(templ)	do_xor_speed((templ), b1, b2)
-
-	printk(KERN_INFO "xor: measuring software checksum speed\n");
-	template_list = NULL;
-	XOR_TRY_TEMPLATES;
+	pr_info("xor: measuring software checksum speed\n");
 	fastest = template_list;
-	for (f = fastest; f; f = f->next)
+	for (f = template_list; f; f = f->next) {
+		do_xor_speed(f, b1, b2);
 		if (f->speed > fastest->speed)
 			fastest = f;
-
+	}
+	active_template = fastest;
 	pr_info("xor: using function: %s (%d MB/sec)\n",
 	       fastest->name, fastest->speed);
 
+	free_pages((unsigned long)b1, 2);
+	return 0;
+}
+
+static int __init xor_init(void)
+{
+	/*
+	 * If this arch/cpu has a short-circuited selection, don't loop through
+	 * all the possible functions, just use the best one.
+	 */
+	active_template = XOR_SELECT_TEMPLATE(NULL);
+	if (active_template) {
+		pr_info("xor: automatically using best checksumming function   %-10s\n",
+			active_template->name);
+		xor_forced = true;
+		return 0;
+	}
+
+#define xor_speed	do_xor_register
+	XOR_TRY_TEMPLATES;
 #undef xor_speed
 
-	free_pages((unsigned long)b1, 2);
-out:
-	active_template = fastest;
+#ifdef MODULE
+	return calibrate_xor_blocks();
+#else
+	/*
+	 * Pick the first template as the temporary default until calibration
+	 * happens.
+	 */
+	active_template = template_list;
 	return 0;
+#endif
 }
 
-static __exit void xor_exit(void) { }
+static __exit void xor_exit(void)
+{
+}
 
 MODULE_DESCRIPTION("RAID-5 checksumming functions");
 MODULE_LICENSE("GPL");
 
+/*
+ * When built-in we must register the default template before md, but we don't
+ * want calibration to run that early as that would delay the boot process.
+ */
 #ifndef MODULE
-/* when built-in xor.o must initialize before drivers/md/md.o */
-core_initcall(register_xor_blocks);
+__initcall(calibrate_xor_blocks);
 #endif
-
-module_init(calibrate_xor_blocks);
+core_initcall(xor_init);
 module_exit(xor_exit);
-- 
2.47.3[PATCH 06/25] xor: cleanup registration and probingChristoph Hellwig <hch@lst.de> undefinedAndrew Morton <akpm@linux-foundation.org> undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined