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>
diff --git a/arch/x86/include/asm/device.h b/arch/x86/include/asm/device.h
index 684ed6c..b2d0b4c 100644
--- a/arch/x86/include/asm/device.h
+++ b/arch/x86/include/asm/device.h
@@ -3,7 +3,7 @@
 
 struct dev_archdata {
 #ifdef CONFIG_X86_DEV_DMA_OPS
-	struct dma_map_ops *dma_ops;
+	const struct dma_map_ops *dma_ops;
 #endif
 #if defined(CONFIG_INTEL_IOMMU) || defined(CONFIG_AMD_IOMMU)
 	void *iommu; /* hook for IOMMU specific extension */
@@ -13,7 +13,7 @@ struct dev_archdata {
 #if defined(CONFIG_X86_DEV_DMA_OPS) && defined(CONFIG_PCI_DOMAINS)
 struct dma_domain {
 	struct list_head node;
-	struct dma_map_ops *dma_ops;
+	const struct dma_map_ops *dma_ops;
 	int domain_nr;
 };
 void add_dma_domain(struct dma_domain *domain);
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 4446162..5e47728 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -25,9 +25,9 @@ extern int iommu_merge;
 extern struct device x86_dma_fallback_dev;
 extern int panic_on_overflow;
 
-extern struct dma_map_ops *dma_ops;
+extern const struct dma_map_ops *dma_ops;
 
-static inline struct dma_map_ops *get_dma_ops(struct device *dev)
+static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
 {
 #ifndef CONFIG_X86_DEV_DMA_OPS
 	return dma_ops;
diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index 345c99c..7938698 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_X86_IOMMU_H
 #define _ASM_X86_IOMMU_H
 
-extern struct dma_map_ops nommu_dma_ops;
+extern const struct dma_map_ops nommu_dma_ops;
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
 extern int iommu_pass_through;