mm/page_alloc.c: cleanup obsolete KM_USER*

It's been five years now that KM_* kmap flags have been removed and that
we can call clear_highpage from any context.  So we remove prep_zero_pages
accordingly.

Signed-off-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 15 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 159dbbc3375d..7a5cbe7cc9b6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -380,20 +380,6 @@ void prep_compound_page(struct page *page, unsigned long order)
         }
 }
 
-static inline void prep_zero_page(struct page *page, unsigned int order,
-                                                        gfp_t gfp_flags)
-{
-        int i;
-
-        /*
-         * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
-         * and __GFP_HIGHMEM from hard or soft interrupt context.
-         */
-        VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
-        for (i = 0; i < (1 << order); i++)
-                clear_highpage(page + i);
-}
-
 #ifdef CONFIG_DEBUG_PAGEALLOC
 unsigned int _debug_guardpage_minorder;
 bool _debug_pagealloc_enabled __read_mostly;
@@ -975,7 +961,8 @@ static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
         kasan_alloc_pages(page, order);
 
         if (gfp_flags & __GFP_ZERO)
-                prep_zero_page(page, order, gfp_flags);
+                for (i = 0; i < (1 << order); i++)
+                        clear_highpage(page + i);
 
         if (order && (gfp_flags & __GFP_COMP))
                 prep_compound_page(page, order);