diff options
Diffstat (limited to 'kernel/dma-coherent.c')
| -rw-r--r-- | kernel/dma-coherent.c | 42 |
1 files changed, 31 insertions, 11 deletions
diff --git a/kernel/dma-coherent.c b/kernel/dma-coherent.c index f013a0c2e11..038707404b7 100644 --- a/kernel/dma-coherent.c +++ b/kernel/dma-coherent.c @@ -109,20 +109,40 @@ EXPORT_SYMBOL(dma_mark_declared_memory_occupied); 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) { - *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) - *ret = NULL; + if (!dev) + return 0; + mem = dev->dma_mem; + if (!mem) + return 0; + if (unlikely(size > mem->size)) + 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); |