x86 PAT: change track_pfn_vma_new to take pgprot_t pointer param

Impact: cleanup

Change the protection parameter for track_pfn_vma_new() into a pgprot_t pointer.
Subsequent patch changes the x86 PAT handling to return a compatible
memtype in pgprot_t, if what was requested cannot be allowed due to conflicts.
No fuctionality change in this patch.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/pat.c

@@ -741,7 +741,7 @@ int track_pfn_vma_copy(struct vm_area_struct *vma)
  * Note that this function can be called with caller trying to map only a
  * subrange/page inside the vma.
  */
-int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
+int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
 			unsigned long pfn, unsigned long size)
 {
 	int retval = 0;
@@ -758,14 +758,14 @@ int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
 	if (is_linear_pfn_mapping(vma)) {
 		/* reserve the whole chunk starting from vm_pgoff */
 		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
-		return reserve_pfn_range(paddr, vma_size, prot);
+		return reserve_pfn_range(paddr, vma_size, *prot);
 	}
 
 	/* reserve page by page using pfn and size */
 	base_paddr = (resource_size_t)pfn << PAGE_SHIFT;
 	for (i = 0; i < size; i += PAGE_SIZE) {
 		paddr = base_paddr + i;
-		retval = reserve_pfn_range(paddr, PAGE_SIZE, prot);
+		retval = reserve_pfn_range(paddr, PAGE_SIZE, *prot);
 		if (retval)
 			goto cleanup_ret;
 	}

include/asm-generic/pgtable.h

@@ -301,7 +301,7 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm,
  * track_pfn_vma_new is called when a _new_ pfn mapping is being established
  * for physical range indicated by pfn and size.
  */
-static inline int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
+static inline int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
 					unsigned long pfn, unsigned long size)
 {
 	return 0;
@@ -332,7 +332,7 @@ static inline void untrack_pfn_vma(struct vm_area_struct *vma,
 {
 }
 #else
-extern int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
+extern int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
 				unsigned long pfn, unsigned long size);
 extern int track_pfn_vma_copy(struct vm_area_struct *vma);
 extern void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,

mm/memory.c

@@ -1511,6 +1511,7 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
 			unsigned long pfn)
 {
 	int ret;
+	pgprot_t pgprot = vma->vm_page_prot;
 	/*
 	 * Technically, architectures with pte_special can avoid all these
 	 * restrictions (same for remap_pfn_range).  However we would like
@@ -1525,10 +1526,10 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
 
 	if (addr < vma->vm_start || addr >= vma->vm_end)
 		return -EFAULT;
-	if (track_pfn_vma_new(vma, vma->vm_page_prot, pfn, PAGE_SIZE))
+	if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
 		return -EINVAL;
 
-	ret = insert_pfn(vma, addr, pfn, vma->vm_page_prot);
+	ret = insert_pfn(vma, addr, pfn, pgprot);
 
 	if (ret)
 		untrack_pfn_vma(vma, pfn, PAGE_SIZE);
@@ -1671,7 +1672,7 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
 
 	vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
 
-	err = track_pfn_vma_new(vma, prot, pfn, PAGE_ALIGN(size));
+	err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
 	if (err) {
 		/*
 		 * To indicate that track_pfn related cleanup is not