x86: dma_alloc_coherent sets gfp flags properly

Non real IOMMU implemenations (which doesn't do virtual mappings,
e.g. swiotlb, pci-nommu, etc) need to use proper gfp flags and
dma_mask to allocate pages in their own dma_alloc_coherent()
(allocated page need to be suitable for device's coherent_dma_mask).

This patch makes dma_alloc_coherent do this job so that IOMMUs don't
need to take care of it any more.

Real IOMMU implemenataions can simply ignore the gfp flags.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index ada1c87cafc2bc97acd022d568d872262aac88cf..8e398b56f50baa953cd9475b135cea5a2fb9b687 100644 (file)
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -80,26 +80,11 @@ nommu_alloc_coherent(struct device *hwdev, size_t size,
        int node;
        struct page *page;
 
-       gfp |= __GFP_ZERO;
-
-       dma_mask = hwdev->coherent_dma_mask;
-       if (!dma_mask)
-               dma_mask = *(hwdev->dma_mask);
+       dma_mask = dma_alloc_coherent_mask(hwdev, gfp);
 
-       if (dma_mask < DMA_24BIT_MASK)
-               return NULL;
+       gfp |= __GFP_ZERO;
 
        node = dev_to_node(hwdev);
-
-#ifdef CONFIG_X86_64
-       if (dma_mask <= DMA_32BIT_MASK && !(gfp & GFP_DMA))
-               gfp |= GFP_DMA32;
-#endif
-
-       /* No alloc-free penalty for ISA devices */
-       if (dma_mask == DMA_24BIT_MASK)
-               gfp |= GFP_DMA;
-
 again:
        page = alloc_pages_node(node, gfp, get_order(size));
        if (!page)

diff --git a/include/asm-x86/dma-mapping.h b/include/asm-x86/dma-mapping.h
index ad8b49032d18e44e1e0c7c0aae9a2e1d607b227f..0cc022b9a4a1886493e95dc7086332704ec5729f 100644 (file)
--- a/include/asm-x86/dma-mapping.h
+++ b/include/asm-x86/dma-mapping.h
@@ -239,6 +239,29 @@ static inline int dma_get_cache_alignment(void)
        return boot_cpu_data.x86_clflush_size;
 }
 
+static inline unsigned long dma_alloc_coherent_mask(struct device *dev,
+                                                   gfp_t gfp)
+{
+       unsigned long dma_mask = 0;
+
+       dma_mask = dev->coherent_dma_mask;
+       if (!dma_mask)
+               dma_mask = (gfp & GFP_DMA) ? DMA_24BIT_MASK : DMA_32BIT_MASK;
+
+       return dma_mask;
+}
+
+static inline gfp_t dma_alloc_coherent_gfp_flags(struct device *dev, gfp_t gfp)
+{
+       unsigned long dma_mask = dma_alloc_coherent_mask(dev, gfp);
+
+#ifdef CONFIG_X86_64
+       if (dma_mask <= DMA_32BIT_MASK && !(gfp & GFP_DMA))
+               gfp |= GFP_DMA32;
+#endif
+       return gfp;
+}
+
 static inline void *
 dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
                gfp_t gfp)
@@ -259,10 +282,11 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
        if (!dev->dma_mask)
                return NULL;
 
-       if (ops->alloc_coherent)
-               return ops->alloc_coherent(dev, size,
-                               dma_handle, gfp);
-       return NULL;
+       if (!ops->alloc_coherent)
+               return NULL;
+
+       return ops->alloc_coherent(dev, size, dma_handle,
+                                  dma_alloc_coherent_gfp_flags(dev, gfp));
 }
 
 static inline void dma_free_coherent(struct device *dev, size_t size,