mm: do not use double negation for testing page flags

With the discussion[1], I found it seems there are every PageFlags
functions return bool at this moment so we don't need double negation
any more.  Although it's not a problem to keep it, it makes future users
confused to use double negation for them, too.

Remove such possibility.

[1] https://marc.info/?l=linux-kernel&m=148881578820434

Frankly sepaking, I like every PageFlags to return bool instead of int.
It will make it clear.  AFAIR, Chen Gang had tried it but don't know why
it was not merged at that time.

http://lkml.kernel.org/r/1469336184-1904-1-git-send-email-chengang@emindsoft.com.cn

Link: http://lkml.kernel.org/r/1488868597-32222-1-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 88e4b1737c90dd6c48688f573f2b4234073b0180..7cb9c88bb4a33ca11c3266f398ffffb53c5afc13 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -548,7 +548,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
                 * The page must only be referenced by the scanned process
                 * and page swap cache.
                 */
-               if (page_count(page) != 1 + !!PageSwapCache(page)) {
+               if (page_count(page) != 1 + PageSwapCache(page)) {
                        unlock_page(page);
                        result = SCAN_PAGE_COUNT;
                        goto out;
@@ -1181,7 +1181,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
                 * The page must only be referenced by the scanned process
                 * and page swap cache.
                 */
-               if (page_count(page) != 1 + !!PageSwapCache(page)) {
+               if (page_count(page) != 1 + PageSwapCache(page)) {
                        result = SCAN_PAGE_COUNT;
                        goto out_unmap;
                }