From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Fri, 19 Aug 2016 12:19:30 +0000 (+0200)
Subject: crypto: xor - skip speed test if the xor function is selected automatically
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=39457acda9139bb078d1b8f974651a194a397060;p=linux-beck.git

crypto: xor - skip speed test if the xor function is selected automatically

If the architecture selected the xor function with XOR_SELECT_TEMPLATE
the speed result of the do_xor_speed benchmark is of limited value.
The speed measurement increases the bootup time a little, which can
makes a difference for kernels used in container like virtual machines.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/crypto/xor.c b/crypto/xor.c
index 35d6b3adf230..b8975d92cd94 100644
--- a/crypto/xor.c
+++ b/crypto/xor.c
@@ -109,6 +109,18 @@ calibrate_xor_blocks(void)
 	void *b1, *b2;
 	struct xor_block_template *f, *fastest;
 
+	fastest = NULL;
+
+#ifdef XOR_SELECT_TEMPLATE
+	fastest = XOR_SELECT_TEMPLATE(fastest);
+	if (fastest) {
+		printk(KERN_INFO "xor: automatically using best "
+				 "checksumming function   %-10s\n",
+		       fastest->name);
+		goto out;
+	}
+#endif
+
 	/*
 	 * Note: Since the memory is not actually used for _anything_ but to
 	 * test the XOR speed, we don't really want kmemcheck to warn about
@@ -126,36 +138,22 @@ calibrate_xor_blocks(void)
 	 * all the possible functions, just test the best one
 	 */
 
-	fastest = NULL;
-
-#ifdef XOR_SELECT_TEMPLATE
-		fastest = XOR_SELECT_TEMPLATE(fastest);
-#endif
-
 #define xor_speed(templ)	do_xor_speed((templ), b1, b2)
 
-	if (fastest) {
-		printk(KERN_INFO "xor: automatically using best "
-				 "checksumming function:\n");
-		xor_speed(fastest);
-		goto out;
-	} else {
-		printk(KERN_INFO "xor: measuring software checksum speed\n");
-		XOR_TRY_TEMPLATES;
-		fastest = template_list;
-		for (f = fastest; f; f = f->next)
-			if (f->speed > fastest->speed)
-				fastest = f;
-	}
+	printk(KERN_INFO "xor: measuring software checksum speed\n");
+	XOR_TRY_TEMPLATES;
+	fastest = template_list;
+	for (f = fastest; f; f = f->next)
+		if (f->speed > fastest->speed)
+			fastest = f;
 
 	printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
 	       fastest->name, fastest->speed / 1000, fastest->speed % 1000);
 
 #undef xor_speed
 
- out:
 	free_pages((unsigned long)b1, 2);
-
+out:
 	active_template = fastest;
 	return 0;
 }