Messages in this thread | | | Date | Fri, 15 Mar 2019 02:06:49 -0700 | From | Christoph Hellwig <> | Subject | Re: [RFC][PATCH 3/5 v2] dma-buf: heaps: Add system heap to dmabuf heaps |
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> + 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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