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>
diff --git a/kernel/dma-coherent.c b/kernel/dma-coherent.c
index 4bdcea8..8056d08 100644
--- a/kernel/dma-coherent.c
+++ b/kernel/dma-coherent.c
@@ -109,34 +109,38 @@
int dma_alloc_from_coherent(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret)
{
- struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
+ struct dma_coherent_mem *mem;
int order = get_order(size);
+ int pageno;
- if (mem) {
- int page = bitmap_find_free_region(mem->bitmap, mem->size,
- order);
- if (page >= 0) {
- /*
- * Memory was found in the per-device arena.
- */
- *dma_handle = mem->device_base + (page << PAGE_SHIFT);
- *ret = mem->virt_base + (page << PAGE_SHIFT);
- memset(*ret, 0, size);
- } else if (mem->flags & DMA_MEMORY_EXCLUSIVE) {
- /*
- * The per-device arena is exhausted and we are not
- * permitted to fall back to generic memory.
- */
- *ret = NULL;
- } else {
- /*
- * The per-device arena is exhausted and we are
- * permitted to fall back to generic memory.
- */
- return 0;
- }
+ if (!dev)
+ return 0;
+ mem = dev->dma_mem;
+ if (!mem)
+ return 0;
+
+ pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
+ if (pageno >= 0) {
+ /*
+ * Memory was found in the per-device arena.
+ */
+ *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
+ *ret = mem->virt_base + (pageno << PAGE_SHIFT);
+ memset(*ret, 0, size);
+ } else if (mem->flags & DMA_MEMORY_EXCLUSIVE) {
+ /*
+ * The per-device arena is exhausted and we are not
+ * permitted to fall back to generic memory.
+ */
+ *ret = NULL;
+ } else {
+ /*
+ * The per-device arena is exhausted and we are
+ * permitted to fall back to generic memory.
+ */
+ return 0;
}
- return (mem != NULL);
+ return 1;
}
EXPORT_SYMBOL(dma_alloc_from_coherent);
