mm: cleanup the gfp_mask handling in __vmalloc_area_node

Patch series "two small vmalloc cleanups".

This patch (of 2):

__vmalloc_area_node currently has four different gfp_t variables to
just express this simple logic:

 - use the passed in mask, plus __GFP_NOWARN and __GFP_HIGHMEM (if
   suitable) for the underlying page allocation
 - use just the reclaim flags from the passed in mask plus __GFP_ZERO
   for allocating the page array

Simplify this down to just use the pre-existing nested_gfp as-is for
the page array allocation, and just the passed in gfp_mask for the
page allocation, after conditionally ORing __GFP_HIGHMEM into it.  This
also makes the allocation warning a little more correct.

Also initialize two variables at the time of declaration while touching
this area.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lkml.kernel.org/r/20201002124035.1539300-1-hch@lst.de
Link: https://lkml.kernel.org/r/20201002124035.1539300-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5c61bf8..acd11d3 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2461,21 +2461,19 @@ EXPORT_SYMBOL_GPL(vmap_pfn);
 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
                                 pgprot_t prot, int node)
 {
-       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_NOWARN;
-       const gfp_t highmem_mask = (gfp_mask & (GFP_DMA | GFP_DMA32)) ?
-                                       0 :
-                                       __GFP_HIGHMEM;
+       unsigned int nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
+       unsigned int array_size = nr_pages * sizeof(struct page *), i;
+       struct page **pages;
 
-       nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
-       array_size = (nr_pages * sizeof(struct page *));
+       gfp_mask |= __GFP_NOWARN;
+       if (!(gfp_mask & (GFP_DMA | GFP_DMA32)))
+               gfp_mask |= __GFP_HIGHMEM;
 
        /* Please note that the recursion is strictly bounded. */
        if (array_size > PAGE_SIZE) {
-               pages = __vmalloc_node(array_size, 1, nested_gfp|highmem_mask,
-                               node, area->caller);
+               pages = __vmalloc_node(array_size, 1, nested_gfp, node,
+                                       area->caller);
        } else {
                pages = kmalloc_node(array_size, nested_gfp, node);
        }
@@ -2493,9 +2491,9 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
                struct page *page;
 
                if (node == NUMA_NO_NODE)
-                       page = alloc_page(alloc_mask|highmem_mask);
+                       page = alloc_page(gfp_mask);
                else
-                       page = alloc_pages_node(node, alloc_mask|highmem_mask, 0);
+                       page = alloc_pages_node(node, gfp_mask, 0);
 
                if (unlikely(!page)) {
                        /* Successfully allocated i pages, free them in __vfree() */