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    SubjectRe: [RFC][PATCH 3/5 v2] dma-buf: heaps: Add system heap to dmabuf heaps
    > +	i = sg_alloc_table(table, npages, GFP_KERNEL);
    > + if (i)
    > + goto err1;
    > + for_each_sg(table->sgl, sg, table->nents, i) {
    > + struct page *page;
    > +
    > + page = alloc_page(GFP_KERNEL);
    > + if (!page)
    > + goto err2;
    > + sg_set_page(sg, page, PAGE_SIZE, 0);
    > + }

    Given that one if not the primary intent here is to DMA map the memory
    this is a bad idea, as it might require bounce buffering.

    What we really want here is something like this:

    http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-noncoherent-allocator.3

    And I wonder if the S/G building should also move into common code
    instead of being duplicated everywhere.

    > +static int system_heap_create(void)
    > +{
    > + struct system_heap *sys_heap;
    > +
    > + sys_heap = kzalloc(sizeof(*sys_heap), GFP_KERNEL);
    > + if (!sys_heap)
    > + return -ENOMEM;
    > + sys_heap->heap.name = "system_heap";
    > + sys_heap->heap.ops = &system_heap_ops;
    > +
    > + dma_heap_add(&sys_heap->heap);

    Why is this dynamically allocated?

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