xen-blkfront: use bitmap_set() and bitmap_clear()

Use bitmap_set and bitmap_clear rather than modifying individual bits
in a memory region.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xensource.com
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/block/xen-blkfront.c

@@ -43,6 +43,7 @@
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/scatterlist.h>
+#include <linux/bitmap.h>
 
 #include <xen/xen.h>
 #include <xen/xenbus.h>
@@ -177,8 +178,7 @@ static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
 
 	spin_lock(&minor_lock);
 	if (find_next_bit(minors, end, minor) >= end) {
-		for (; minor < end; ++minor)
-			__set_bit(minor, minors);
+		bitmap_set(minors, minor, nr);
 		rc = 0;
 	} else
 		rc = -EBUSY;
@@ -193,8 +193,7 @@ static void xlbd_release_minors(unsigned int minor, unsigned int nr)
 
 	BUG_ON(end > nr_minors);
 	spin_lock(&minor_lock);
-	for (; minor < end; ++minor)
-		__clear_bit(minor, minors);
+	bitmap_clear(minors,  minor, nr);
 	spin_unlock(&minor_lock);
 }