treewide: Constify most dma_map_ops structures

Most dma_map_ops structures are never modified. Constify these
structures such that these can be write-protected. This patch
has been generated as follows:

git grep -l 'struct dma_map_ops' |
  xargs -d\\n sed -i \
    -e 's/struct dma_map_ops/const struct dma_map_ops/g' \
    -e 's/const struct dma_map_ops {/struct dma_map_ops {/g' \
    -e 's/^const struct dma_map_ops;$/struct dma_map_ops;/' \
    -e 's/const const struct dma_map_ops /const struct dma_map_ops /g';
sed -i -e 's/const \(struct dma_map_ops intel_dma_ops\)/\1/' \
  $(git grep -l 'struct dma_map_ops intel_dma_ops');
sed -i -e 's/const \(struct dma_map_ops dma_iommu_ops\)/\1/' \
  $(git grep -l 'struct dma_map_ops' | grep ^arch/powerpc);
sed -i -e '/^struct vmd_dev {$/,/^};$/ s/const \(struct dma_map_ops[[:blank:]]dma_ops;\)/\1/' \
       -e '/^static void vmd_setup_dma_ops/,/^}$/ s/const \(struct dma_map_ops \*dest\)/\1/' \
       -e 's/const \(struct dma_map_ops \*dest = \&vmd->dma_ops\)/\1/' \
    drivers/pci/host/*.c
sed -i -e '/^void __init pci_iommu_alloc(void)$/,/^}$/ s/dma_ops->/intel_dma_ops./' arch/ia64/kernel/pci-dma.c
sed -i -e 's/static const struct dma_map_ops sn_dma_ops/static struct dma_map_ops sn_dma_ops/' arch/ia64/sn/pci/pci_dma.c
sed -i -e 's/(const struct dma_map_ops \*)//' drivers/misc/mic/bus/vop_bus.c

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Russell King <linux@armlinux.org.uk>
Cc: x86@kernel.org
Signed-off-by: Doug Ledford <dledford@redhat.com>

arch/powerpc/kernel/dma-swiotlb.c

@@ -46,7 +46,7 @@ static u64 swiotlb_powerpc_get_required(struct device *dev)
  * map_page, and unmap_page on highmem, use normal dma_ops
  * for everything else.
  */
-struct dma_map_ops swiotlb_dma_ops = {
+const struct dma_map_ops swiotlb_dma_ops = {
 	.alloc = __dma_direct_alloc_coherent,
 	.free = __dma_direct_free_coherent,
 	.mmap = dma_direct_mmap_coherent,

arch/powerpc/kernel/dma.c

@@ -274,7 +274,7 @@ static inline void dma_direct_sync_single(struct device *dev,
 }
 #endif
 
-struct dma_map_ops dma_direct_ops = {
+const struct dma_map_ops dma_direct_ops = {
 	.alloc				= dma_direct_alloc_coherent,
 	.free				= dma_direct_free_coherent,
 	.mmap				= dma_direct_mmap_coherent,
@@ -316,7 +316,7 @@ EXPORT_SYMBOL(dma_set_coherent_mask);
 
 int __dma_set_mask(struct device *dev, u64 dma_mask)
 {
-	struct dma_map_ops *dma_ops = get_dma_ops(dev);
+	const struct dma_map_ops *dma_ops = get_dma_ops(dev);
 
 	if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL))
 		return dma_ops->set_dma_mask(dev, dma_mask);
@@ -344,7 +344,7 @@ EXPORT_SYMBOL(dma_set_mask);
 
 u64 __dma_get_required_mask(struct device *dev)
 {
-	struct dma_map_ops *dma_ops = get_dma_ops(dev);
+	const struct dma_map_ops *dma_ops = get_dma_ops(dev);
 
 	if (unlikely(dma_ops == NULL))
 		return 0;

arch/powerpc/kernel/pci-common.c

@@ -59,14 +59,14 @@ resource_size_t isa_mem_base;
 EXPORT_SYMBOL(isa_mem_base);
 
 
-static struct dma_map_ops *pci_dma_ops = &dma_direct_ops;
+static const struct dma_map_ops *pci_dma_ops = &dma_direct_ops;
 
-void set_pci_dma_ops(struct dma_map_ops *dma_ops)
+void set_pci_dma_ops(const struct dma_map_ops *dma_ops)
 {
 	pci_dma_ops = dma_ops;
 }
 
-struct dma_map_ops *get_pci_dma_ops(void)
+const struct dma_map_ops *get_pci_dma_ops(void)
 {
 	return pci_dma_ops;
 }