mm/vmalloc.c: don't unconditonally use __GFP_HIGHMEM

Commit 19809c2 ("mm, vmalloc: use __GFP_HIGHMEM implicitly") added
use of __GFP_HIGHMEM for allocations.  vmalloc_32 may use
GFP_DMA/GFP_DMA32 which does not play nice with __GFP_HIGHMEM and will
trigger a BUG in gfp_zone.

Only add __GFP_HIGHMEM if we aren't using GFP_DMA/GFP_DMA32.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1482249
Link: http://lkml.kernel.org/r/20170816220705.31374-1-labbott@redhat.com
Fixes: 19809c2 ("mm, vmalloc: use __GFP_HIGHMEM implicitly")
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -1671,15 +1671,18 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	struct page **pages;
 	unsigned int nr_pages, array_size, i;
 	const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
-	const gfp_t alloc_mask = gfp_mask | __GFP_HIGHMEM | __GFP_NOWARN;
+	const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
+	const gfp_t highmem_mask = (gfp_mask & (GFP_DMA | GFP_DMA32)) ?
+					0 :
+					__GFP_HIGHMEM;
 
 	nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
 	array_size = (nr_pages * sizeof(struct page *));
 
 	area->nr_pages = nr_pages;
 	/* Please note that the recursion is strictly bounded. */
 	if (array_size > PAGE_SIZE) {
-		pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM,
+		pages = __vmalloc_node(array_size, 1, nested_gfp|highmem_mask,
 				PAGE_KERNEL, node, area->caller);
 	} else {
 		pages = kmalloc_node(array_size, nested_gfp, node);
@@ -1700,17 +1703,17 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 		}
 
 		if (node == NUMA_NO_NODE)
-			page = alloc_page(alloc_mask);
+			page = alloc_page(alloc_mask|highmem_mask);
 		else
-			page = alloc_pages_node(node, alloc_mask, 0);
+			page = alloc_pages_node(node, alloc_mask|highmem_mask, 0);
 
 		if (unlikely(!page)) {
 			/* Successfully allocated i pages, free them in __vunmap() */
 			area->nr_pages = i;
 			goto fail;
 		}
 		area->pages[i] = page;
-		if (gfpflags_allow_blocking(gfp_mask))
+		if (gfpflags_allow_blocking(gfp_mask|highmem_mask))
 			cond_resched();
 	}