dma_alloc_coherent: clean it up
This thing was rather stupidly coded. Rework it all prior to making changes. Also, rename local variable `page': kernel readers expect something called `page' to have type `struct page *'. Cc: Guennadi Liakhovetski <lg@denx.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Dmitry Baryshkov <dbaryshkov@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -109,34 +109,38 @@ EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
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int dma_alloc_from_coherent(struct device *dev, ssize_t size,
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dma_addr_t *dma_handle, void **ret)
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{
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struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
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struct dma_coherent_mem *mem;
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int order = get_order(size);
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int pageno;
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if (mem) {
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int page = bitmap_find_free_region(mem->bitmap, mem->size,
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order);
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if (page >= 0) {
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/*
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* Memory was found in the per-device arena.
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*/
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*dma_handle = mem->device_base + (page << PAGE_SHIFT);
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*ret = mem->virt_base + (page << PAGE_SHIFT);
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memset(*ret, 0, size);
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} else if (mem->flags & DMA_MEMORY_EXCLUSIVE) {
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/*
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* The per-device arena is exhausted and we are not
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* permitted to fall back to generic memory.
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*/
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*ret = NULL;
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} else {
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/*
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* The per-device arena is exhausted and we are
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* permitted to fall back to generic memory.
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*/
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return 0;
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}
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if (!dev)
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return 0;
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mem = dev->dma_mem;
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if (!mem)
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return 0;
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pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
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if (pageno >= 0) {
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/*
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* Memory was found in the per-device arena.
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*/
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*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
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*ret = mem->virt_base + (pageno << PAGE_SHIFT);
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memset(*ret, 0, size);
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} else if (mem->flags & DMA_MEMORY_EXCLUSIVE) {
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/*
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* The per-device arena is exhausted and we are not
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* permitted to fall back to generic memory.
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*/
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*ret = NULL;
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} else {
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/*
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* The per-device arena is exhausted and we are
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* permitted to fall back to generic memory.
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*/
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return 0;
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}
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return (mem != NULL);
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return 1;
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}
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EXPORT_SYMBOL(dma_alloc_from_coherent);
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