x86, pat: separate the pfn attribute tracking for remap_pfn_range and vm_insert_pfn

With PAT enabled, vm_insert_pfn() looks up the existing pfn memory
attribute and uses it.  Expectation is that the driver reserves the
memory attributes for the pfn before calling vm_insert_pfn().

remap_pfn_range() (when called for the whole vma) will setup a new
attribute (based on the prot argument) for the specified pfn range.
This addresses the legacy usage which typically calls remap_pfn_range()
with a desired memory attribute.  For ranges smaller than the vma size
(which is typically not the case), remap_pfn_range() will use the
existing memory attribute for the pfn range.

Expose two different API's for these different behaviors.
track_pfn_insert() for tracking the pfn attribute set by vm_insert_pfn()
and track_pfn_remap() for the remap_pfn_range().

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'.

[khlebnikov@openvz.org: Clear checks in track_pfn_remap()]
[akpm@linux-foundation.org: tweak a few comments]
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 8 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 57361708d1a5..6bef278ad303 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1060,7 +1060,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
                  * We do not free on error cases below as remove_vma
                  * gets called on error from higher level routine
                  */
-                ret = track_pfn_vma_copy(vma);
+                ret = track_pfn_copy(vma);
                 if (ret)
                         return ret;
         }
@@ -1328,7 +1328,7 @@ static void unmap_single_vma(struct mmu_gather *tlb,
                 uprobe_munmap(vma, start, end);
 
         if (unlikely(is_pfn_mapping(vma)))
-                untrack_pfn_vma(vma, 0, 0);
+                untrack_pfn(vma, 0, 0);
 
         if (start != end) {
                 if (unlikely(is_vm_hugetlb_page(vma))) {
@@ -2162,14 +2162,11 @@ 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, &pgprot, pfn, PAGE_SIZE))
+        if (track_pfn_insert(vma, &pgprot, pfn))
                 return -EINVAL;
 
         ret = insert_pfn(vma, addr, pfn, pgprot);
 
-        if (ret)
-                untrack_pfn_vma(vma, pfn, PAGE_SIZE);
-
         return ret;
 }
 EXPORT_SYMBOL(vm_insert_pfn);
@@ -2311,7 +2308,7 @@ 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_remap(vma, &prot, pfn, PAGE_ALIGN(size));
         if (err) {
                 /*
                  * To indicate that track_pfn related cleanup is not
@@ -2335,7 +2332,7 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
         } while (pgd++, addr = next, addr != end);
 
         if (err)
-                untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
+                untrack_pfn(vma, pfn, PAGE_ALIGN(size));
 
         return err;
 }