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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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