/dev/mem: remove redundant test on len

The len test in write_kmem() is always true, so can be reduced.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/mem.c

@@ -581,7 +581,6 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
 
 			if (len > PAGE_SIZE)
 				len = PAGE_SIZE;
-			if (len) {
 			written = copy_from_user(kbuf, buf, len);
 			if (written) {
 				if (wrote + virtr)
@@ -589,7 +588,6 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
 				free_page((unsigned long)kbuf);
 				return -EFAULT;
 			}
-			}
 			len = vwrite(kbuf, (char *)p, len);
 			count -= len;
 			buf += len;