[PATCH v2 6/6] powernv/memtrace: use __GFP_ZERO with alloc_contig_pages()

[David Hildenbrand]

alloc_contig_pages()->alloc_contig_range() now supports __GFP_ZERO,
so let's use that instead to resolve our TODO.

Signed-off-by: David Hildenbrand <da...@redhat.com>
---
 arch/powerpc/platforms/powernv/memtrace.c | 31 +++++------------------
 1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/memtrace.c 
b/arch/powerpc/platforms/powernv/memtrace.c
index 877720c64515..4ac9808e55a4 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -88,26 +88,6 @@ static void flush_dcache_range_chunked(unsigned long start, 
unsigned long stop,
        }
 }
 
-static void memtrace_clear_range(unsigned long start_pfn,
-                                unsigned long nr_pages)
-{
-       unsigned long pfn;
-
-       /* As HIGHMEM does not apply, use clear_page() directly. */
-       for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) {
-               if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
-                       cond_resched();
-               clear_page(__va(PFN_PHYS(pfn)));
-       }
-       /*
-        * Before we go ahead and use this range as cache inhibited range
-        * flush the cache.
-        */
-       flush_dcache_range_chunked((unsigned long)pfn_to_kaddr(start_pfn),
-                                  (unsigned long)pfn_to_kaddr(start_pfn + 
nr_pages),
-                                  FLUSH_CHUNK_SIZE);
-}
-
 static u64 memtrace_alloc_node(u32 nid, u64 size)
 {
        const unsigned long nr_pages = PHYS_PFN(size);
@@ -119,17 +99,18 @@ static u64 memtrace_alloc_node(u32 nid, u64 size)
         * by alloc_contig_pages().
         */
        page = alloc_contig_pages(nr_pages, GFP_KERNEL | __GFP_THISNODE |
-                                 __GFP_NOWARN, nid, NULL);
+                                 __GFP_NOWARN | __GFP_ZERO, nid, NULL);
        if (!page)
                return 0;
        start_pfn = page_to_pfn(page);
 
        /*
-        * Clear the range while we still have a linear mapping.
-        *
-        * TODO: use __GFP_ZERO with alloc_contig_pages() once supported.
+        * Before we go ahead and use this range as cache inhibited range
+        * flush the cache.
         */
-       memtrace_clear_range(start_pfn, nr_pages);
+       flush_dcache_range_chunked((unsigned long)pfn_to_kaddr(start_pfn),
+                                  (unsigned long)pfn_to_kaddr(start_pfn + 
nr_pages),
+                                  FLUSH_CHUNK_SIZE);
 
        /*
         * Set pages PageOffline(), to indicate that nobody (e.g., hibernation,
-- 
2.47.1