[PATCH v4 7/9] mm/mremap: Move TLB flush outside page table lock

[Aneesh Kumar K.V]

Move TLB flush outside page table lock so that kernel does
less with page table lock held. Releasing the ptl with old
TLB contents still valid will behave such that such access
happened before the level3 or level2 entry update.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
---
 mm/mremap.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 0e7b11daafee..7ac1df8e6d51 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -259,7 +259,7 @@ static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 	 * We don't have to worry about the ordering of src and dst
 	 * ptlocks because exclusive mmap_lock prevents deadlock.
 	 */
-	old_ptl = pmd_lock(vma->vm_mm, old_pmd);
+	old_ptl = pmd_lock(mm, old_pmd);
 	new_ptl = pmd_lockptr(mm, new_pmd);
 	if (new_ptl != old_ptl)
 		spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
@@ -271,11 +271,11 @@ static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 	VM_BUG_ON(!pmd_none(*new_pmd));
 	pmd_populate(mm, new_pmd, (pgtable_t)pmd_page_vaddr(pmd));
 
-	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PMD_SIZE, true);
 	if (new_ptl != old_ptl)
 		spin_unlock(new_ptl);
 	spin_unlock(old_ptl);
 
+	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PMD_SIZE, true);
 	return true;
 }
 #else
@@ -306,7 +306,7 @@ static bool move_normal_pud(struct vm_area_struct *vma, unsigned long old_addr,
 	 * We don't have to worry about the ordering of src and dst
 	 * ptlocks because exclusive mmap_lock prevents deadlock.
 	 */
-	old_ptl = pud_lock(vma->vm_mm, old_pud);
+	old_ptl = pud_lock(mm, old_pud);
 	new_ptl = pud_lockptr(mm, new_pud);
 	if (new_ptl != old_ptl)
 		spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
@@ -318,11 +318,11 @@ static bool move_normal_pud(struct vm_area_struct *vma, unsigned long old_addr,
 	VM_BUG_ON(!pud_none(*new_pud));
 
 	pud_populate(mm, new_pud, (pmd_t *)pud_page_vaddr(pud));
-	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PUD_SIZE, true);
 	if (new_ptl != old_ptl)
 		spin_unlock(new_ptl);
 	spin_unlock(old_ptl);
 
+	flush_pte_tlb_pwc_range(vma, old_addr, old_addr + PUD_SIZE, true);
 	return true;
 }
 #else
-- 
2.30.2