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Subject[PATCH] adjust gfp mask passed on nested vmalloc() invocation
- fix a latent bug resulting from blindly or-ing in __GFP_ZERO, since
the combination of this and __GFP_HIGHMEM (possibly passed into the
function) is forbidden in interrupt context
- avoid wasting more precious resources (DMA or DMA32 pools), when
being called through vmalloc_32{,_user}()
- explicitly allow using high memory here even if the outer allocation
request doesn't allow it, unless is collides with __GFP_ZERO
Signed-off-by: Jan Beulich <jbeulich@novell.com>

---
mm/vmalloc.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--- linux-2.6.32-rc3/mm/vmalloc.c 2009-10-05 11:59:56.000000000 +0200
+++ 2.6.32-rc3-vmalloc-nested-gfp/mm/vmalloc.c 2009-10-05 08:40:36.000000000 +0200
@@ -1410,6 +1410,7 @@ static void *__vmalloc_area_node(struct
{
struct page **pages;
unsigned int nr_pages, array_size, i;
+ gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;

nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
array_size = (nr_pages * sizeof(struct page *));
@@ -1417,13 +1418,16 @@ static void *__vmalloc_area_node(struct
area->nr_pages = nr_pages;
/* Please note that the recursion is strictly bounded. */
if (array_size > PAGE_SIZE) {
- pages = __vmalloc_node(array_size, gfp_mask | __GFP_ZERO,
+#ifdef CONFIG_HIGHMEM
+ /* See the comment in prep_zero_page(). */
+ if (!in_interrupt())
+ nested_gfp |= __GFP_HIGHMEM;
+#endif
+ pages = __vmalloc_node(array_size, nested_gfp,
PAGE_KERNEL, node, caller);
area->flags |= VM_VPAGES;
} else {
- pages = kmalloc_node(array_size,
- (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO,
- node);
+ pages = kmalloc_node(array_size, nested_gfp, node);
}
area->pages = pages;
area->caller = caller;




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