dma-mapping: use unsigned long for dma_attrs

The dma-mapping core and the implementations do not change the DMA
attributes passed by pointer.  Thus the pointer can point to const data.
However the attributes do not have to be a bitfield.  Instead unsigned
long will do fine:

1. This is just simpler.  Both in terms of reading the code and setting
   attributes.  Instead of initializing local attributes on the stack
   and passing pointer to it to dma_set_attr(), just set the bits.

2. It brings safeness and checking for const correctness because the
   attributes are passed by value.

Semantic patches for this change (at least most of them):

    virtual patch
    virtual context

    @r@
    identifier f, attrs;

    @@
    f(...,
    - struct dma_attrs *attrs
    + unsigned long attrs
    , ...)
    {
    ...
    }

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

and

    // Options: --all-includes
    virtual patch
    virtual context

    @r@
    identifier f, attrs;
    type t;

    @@
    t f(..., struct dma_attrs *attrs);

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris]
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm]
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp]
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core]
Acked-by: David Vrabel <david.vrabel@citrix.com> [xen]
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb]
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 14 deletions

diff --git a/arch/ia64/sn/pci/pci_dma.c b/arch/ia64/sn/pci/pci_dma.c
index 8f59907007cb..74c934a997bb 100644
--- a/arch/ia64/sn/pci/pci_dma.c
+++ b/arch/ia64/sn/pci/pci_dma.c
@@ -77,7 +77,7 @@ EXPORT_SYMBOL(sn_dma_set_mask);
  */
 static void *sn_dma_alloc_coherent(struct device *dev, size_t size,
                                    dma_addr_t * dma_handle, gfp_t flags,
-                                   struct dma_attrs *attrs)
+                                   unsigned long attrs)
 {
         void *cpuaddr;
         unsigned long phys_addr;
@@ -138,7 +138,7 @@ static void *sn_dma_alloc_coherent(struct device *dev, size_t size,
  * any associated IOMMU mappings.
  */
 static void sn_dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
-                                 dma_addr_t dma_handle, struct dma_attrs *attrs)
+                                 dma_addr_t dma_handle, unsigned long attrs)
 {
         struct pci_dev *pdev = to_pci_dev(dev);
         struct sn_pcibus_provider *provider = SN_PCIDEV_BUSPROVIDER(pdev);
@@ -176,21 +176,18 @@ static void sn_dma_free_coherent(struct device *dev, size_t size, void *cpu_addr
 static dma_addr_t sn_dma_map_page(struct device *dev, struct page *page,
                                   unsigned long offset, size_t size,
                                   enum dma_data_direction dir,
-                                  struct dma_attrs *attrs)
+                                  unsigned long attrs)
 {
         void *cpu_addr = page_address(page) + offset;
         dma_addr_t dma_addr;
         unsigned long phys_addr;
         struct pci_dev *pdev = to_pci_dev(dev);
         struct sn_pcibus_provider *provider = SN_PCIDEV_BUSPROVIDER(pdev);
-        int dmabarr;
-
-        dmabarr = dma_get_attr(DMA_ATTR_WRITE_BARRIER, attrs);
 
         BUG_ON(!dev_is_pci(dev));
 
         phys_addr = __pa(cpu_addr);
-        if (dmabarr)
+        if (attrs & DMA_ATTR_WRITE_BARRIER)
                 dma_addr = provider->dma_map_consistent(pdev, phys_addr,
                                                         size, SN_DMA_ADDR_PHYS);
         else
@@ -218,7 +215,7 @@ static dma_addr_t sn_dma_map_page(struct device *dev, struct page *page,
  */
 static void sn_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
                               size_t size, enum dma_data_direction dir,
-                              struct dma_attrs *attrs)
+                              unsigned long attrs)
 {
         struct pci_dev *pdev = to_pci_dev(dev);
         struct sn_pcibus_provider *provider = SN_PCIDEV_BUSPROVIDER(pdev);
@@ -240,7 +237,7 @@ static void sn_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
  */
 static void sn_dma_unmap_sg(struct device *dev, struct scatterlist *sgl,
                             int nhwentries, enum dma_data_direction dir,
-                            struct dma_attrs *attrs)
+                            unsigned long attrs)
 {
         int i;
         struct pci_dev *pdev = to_pci_dev(dev);
@@ -273,16 +270,13 @@ static void sn_dma_unmap_sg(struct device *dev, struct scatterlist *sgl,
  */
 static int sn_dma_map_sg(struct device *dev, struct scatterlist *sgl,
                          int nhwentries, enum dma_data_direction dir,
-                         struct dma_attrs *attrs)
+                         unsigned long attrs)
 {
         unsigned long phys_addr;
         struct scatterlist *saved_sg = sgl, *sg;
         struct pci_dev *pdev = to_pci_dev(dev);
         struct sn_pcibus_provider *provider = SN_PCIDEV_BUSPROVIDER(pdev);
         int i;
-        int dmabarr;
-
-        dmabarr = dma_get_attr(DMA_ATTR_WRITE_BARRIER, attrs);
 
         BUG_ON(!dev_is_pci(dev));
 
@@ -292,7 +286,7 @@ static int sn_dma_map_sg(struct device *dev, struct scatterlist *sgl,
         for_each_sg(sgl, sg, nhwentries, i) {
                 dma_addr_t dma_addr;
                 phys_addr = SG_ENT_PHYS_ADDRESS(sg);
-                if (dmabarr)
+                if (attrs & DMA_ATTR_WRITE_BARRIER)
                         dma_addr = provider->dma_map_consistent(pdev,
                                                                 phys_addr,
                                                                 sg->length,