On Thu, Jun 18, 2015 at 11:44:22PM +0200, Lorenzo Nava wrote:
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 7e7583d..8e7f402 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -645,15 +645,29 @@ static void *__dma_alloc(struct device *dev, size_t
> size, dma_addr_t *handle,
> size = PAGE_ALIGN(size);
> want_vaddr = !dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs);
>
> - if (is_coherent || nommu())
> + if (nommu()) {
> addr = __alloc_simple_buffer(dev, size, gfp, &page);
> - else if (!(gfp & __GFP_WAIT))
> + goto dma_alloc_done;
> + }
> +
> + if (dev_get_cma_area(dev) && (gfp & __GFP_WAIT)) {
> + addr = __alloc_from_contiguous(dev, size, prot, &page,
> + caller, want_vaddr);
> + goto dma_alloc_done;
> + }
> +
> + if (is_coherent) {
> + addr = __alloc_simple_buffer(dev, size, gfp, &page);
> + goto dma_alloc_done;
> + }
> +
> + if (!(gfp & __GFP_WAIT))
> addr = __alloc_from_pool(size, &page);
> - else if (!dev_get_cma_area(dev))
> - addr = __alloc_remap_buffer(dev, size, gfp, prot, &page,
> caller, want_vaddr);
> else
> - addr = __alloc_from_contiguous(dev, size, prot, &page, caller,
> want_vaddr);
> + addr = __alloc_remap_buffer(dev, size, gfp, prot, &page,
> + caller, want_vaddr);
>
> +dma_alloc_done:
> if (page)
> *handle = pfn_to_dma(dev, page_to_pfn(page));
The logic here looks alright but I would have preferred the original
more concise "if ... else if" constructs than the gotos (just personal
preference).
> @@ -680,9 +694,14 @@ void *arm_dma_alloc(struct device *dev, size_t size,
> dma_addr_t *handle,
> static void *arm_coherent_dma_alloc(struct device *dev, size_t size,
> dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
> {
> - pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
> + pgprot_t prot;
> void *memory;
>
> + if (attrs == NULL)
> + prot = PAGE_KERNEL;
> + else
> + prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
> +
> if (dma_alloc_from_coherent(dev, size, handle, &memory))
> return memory;
I still think this is the wrong way to fix. It doesn't address the
coherent dma mmap operation. I already replied on the previous version
that we should rather have an extra argument "coherent" to
__get_dma_pgprot().
> @@ -735,12 +754,12 @@ static void __arm_dma_free(struct device *dev, size_t
> size, void *cpu_addr,
>
> size = PAGE_ALIGN(size);
>
> - if (is_coherent || nommu()) {
> + if (nommu()) {
> __dma_free_buffer(page, size);
> } else if (__free_from_pool(cpu_addr, size)) {
> return;
You have an unnecessary __free_from_pool() call here in the is_coherent
case.
> } else if (!dev_get_cma_area(dev)) {
> - if (want_vaddr)
> + if (want_vaddr && !is_coherent)
> __dma_free_remap(cpu_addr, size);
> __dma_free_buffer(page, size);
> } else {
--
Catalin
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