x86, pat: remove the dependency on 'vm_pgoff' in track/untrack pfn vma routines

'pfn' argument for track_pfn_vma_new() can be used for reserving the
attribute for the pfn range.  No need to depend on 'vm_pgoff'

Similarly, untrack_pfn_vma() can depend on the 'pfn' argument if it is
non-zero or can use follow_phys() to get the starting value of the pfn
range.

Also the non zero 'size' argument can be used instead of recomputing it
from vma.

This cleanup also prepares the ground for the track/untrack pfn vma
routines to take over the ownership of setting PAT specific vm_flag in the
'vma'.

[[email protected]: Clear pfn to paddr conversion]
Signed-off-by: Suresh Siddha <[email protected]>
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Cc: Venkatesh Pallipadi <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Carsten Otte <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Cc: Eric Paris <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Morris <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Kentaro Takeda <[email protected]>
Cc: Matt Helsley <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Robert Richter <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 19 insertions, 14 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 3d68ef6d2266..de36c886cd38 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -704,21 +704,18 @@ int track_pfn_vma_copy(struct vm_area_struct *vma)
 int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
 			unsigned long pfn, unsigned long size)
 {
+	resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT;
 	unsigned long flags;
-	resource_size_t paddr;
-	unsigned long vma_size = vma->vm_end - vma->vm_start;
 
-	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, 0);
-	}
+	/* reserve the whole chunk starting from paddr */
+	if (is_linear_pfn_mapping(vma))
+		return reserve_pfn_range(paddr, size, prot, 0);
 
 	if (!pat_enabled)
 		return 0;
 
 	/* for vm_insert_pfn and friends, we set prot based on lookup */
-	flags = lookup_memtype(pfn << PAGE_SHIFT);
+	flags = lookup_memtype(paddr);
 	*prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
 			 flags);
 
@@ -728,20 +725,28 @@ int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
 /*
  * untrack_pfn_vma is called while unmapping a pfnmap for a region.
  * untrack can be called for a specific region indicated by pfn and size or
- * can be for the entire vma (in which case size can be zero).
+ * can be for the entire vma (in which case pfn, size are zero).
  */
 void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
 			unsigned long size)
 {
 	resource_size_t paddr;
-	unsigned long vma_size = vma->vm_end - vma->vm_start;
+	unsigned long prot;
 
-	if (is_linear_pfn_mapping(vma)) {
-		/* free the whole chunk starting from vm_pgoff */
-		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
-		free_pfn_range(paddr, vma_size);
+	if (!is_linear_pfn_mapping(vma))
 		return;
+
+	/* free the chunk starting from pfn or the whole chunk */
+	paddr = (resource_size_t)pfn << PAGE_SHIFT;
+	if (!paddr && !size) {
+		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
+			WARN_ON_ONCE(1);
+			return;
+		}
+
+		size = vma->vm_end - vma->vm_start;
 	}
+	free_pfn_range(paddr, size);
 }
 
 pgprot_t pgprot_writecombine(pgprot_t prot)