mm, thp: fix comment inconsistency for swapin readahead functions

After fixing swapin issues, comment lines stayed as in old version.
This patch updates the comments.

Link: http://lkml.kernel.org/r/1468109345-32258-1-git-send-email-ebru.akagunduz@gmail.com
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/khugepaged.c

@@ -891,9 +891,10 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
 		/* do_swap_page returns VM_FAULT_RETRY with released mmap_sem */
 		if (ret & VM_FAULT_RETRY) {
 			down_read(&mm->mmap_sem);
+			if (hugepage_vma_revalidate(mm, address)) {
 				/* vma is no longer available, don't continue to swapin */
-			if (hugepage_vma_revalidate(mm, address))
 				return false;
+			}
 			/* check if the pmd is still valid */
 			if (mm_find_pmd(mm, address) != pmd)
 				return false;
@@ -969,7 +970,7 @@ static void collapse_huge_page(struct mm_struct *mm,
 
 	/*
 	 * __collapse_huge_page_swapin always returns with mmap_sem locked.
-	 * If it fails, release mmap_sem and jump directly out.
+	 * If it fails, we release mmap_sem and jump out_nolock.
 	 * Continuing to collapse causes inconsistency.
 	 */
 	if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) {