hugetlb: unsigned ret cannot be negative

unsigned long ret cannot be negative, but ret can get -EFAULT.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Ken Chen <kenchen@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hugetlbfs/inode.c

@@ -252,6 +252,7 @@ static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 	for (;;) {
 		struct page *page;
 		unsigned long nr, ret;
+		int ra;
 
 		/* nr is the maximum number of bytes to copy from this page */
 		nr = huge_page_size(h);
@@ -274,16 +275,19 @@ static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 			 */
 			ret = len < nr ? len : nr;
 			if (clear_user(buf, ret))
-				ret = -EFAULT;
+				ra = -EFAULT;
+			else
+				ra = 0;
 		} else {
 			/*
 			 * We have the page, copy it to user space buffer.
 			 */
-			ret = hugetlbfs_read_actor(page, offset, buf, len, nr);
+			ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
+			ret = ra;
 		}
-		if (ret < 0) {
+		if (ra < 0) {
 			if (retval == 0)
-				retval = ret;
+				retval = ra;
 			if (page)
 				page_cache_release(page);
 			goto out;