powerpc/mm: use generic version of pmdp_clear_flush()

[mirror_ubuntu-zesty-kernel.git] / arch / powerpc / mm / pgtable_64.c

diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 6bfadf1aa5cbbfadbd7237e5f3da8ac8653a5651..f7775193d745e845df4b2e6b86f9d0de5ceae7fd 100644 (file)
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -554,47 +554,42 @@ unsigned long pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
        return old;
 }
 
-pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address,
-                      pmd_t *pmdp)
+pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
+                         pmd_t *pmdp)
 {
        pmd_t pmd;
 
        VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-       if (pmd_trans_huge(*pmdp)) {
-               pmd = pmdp_get_and_clear(vma->vm_mm, address, pmdp);
-       } else {
-               /*
-                * khugepaged calls this for normal pmd
-                */
-               pmd = *pmdp;
-               pmd_clear(pmdp);
-               /*
-                * Wait for all pending hash_page to finish. This is needed
-                * in case of subpage collapse. When we collapse normal pages
-                * to hugepage, we first clear the pmd, then invalidate all
-                * the PTE entries. The assumption here is that any low level
-                * page fault will see a none pmd and take the slow path that
-                * will wait on mmap_sem. But we could very well be in a
-                * hash_page with local ptep pointer value. Such a hash page
-                * can result in adding new HPTE entries for normal subpages.
-                * That means we could be modifying the page content as we
-                * copy them to a huge page. So wait for parallel hash_page
-                * to finish before invalidating HPTE entries. We can do this
-                * by sending an IPI to all the cpus and executing a dummy
-                * function there.
-                */
-               kick_all_cpus_sync();
-               /*
-                * Now invalidate the hpte entries in the range
-                * covered by pmd. This make sure we take a
-                * fault and will find the pmd as none, which will
-                * result in a major fault which takes mmap_sem and
-                * hence wait for collapse to complete. Without this
-                * the __collapse_huge_page_copy can result in copying
-                * the old content.
-                */
-               flush_tlb_pmd_range(vma->vm_mm, &pmd, address);
-       }
+       VM_BUG_ON(pmd_trans_huge(*pmdp));
+
+       pmd = *pmdp;
+       pmd_clear(pmdp);
+       /*
+        * Wait for all pending hash_page to finish. This is needed
+        * in case of subpage collapse. When we collapse normal pages
+        * to hugepage, we first clear the pmd, then invalidate all
+        * the PTE entries. The assumption here is that any low level
+        * page fault will see a none pmd and take the slow path that
+        * will wait on mmap_sem. But we could very well be in a
+        * hash_page with local ptep pointer value. Such a hash page
+        * can result in adding new HPTE entries for normal subpages.
+        * That means we could be modifying the page content as we
+        * copy them to a huge page. So wait for parallel hash_page
+        * to finish before invalidating HPTE entries. We can do this
+        * by sending an IPI to all the cpus and executing a dummy
+        * function there.
+        */
+       kick_all_cpus_sync();
+       /*
+        * Now invalidate the hpte entries in the range
+        * covered by pmd. This make sure we take a
+        * fault and will find the pmd as none, which will
+        * result in a major fault which takes mmap_sem and
+        * hence wait for collapse to complete. Without this
+        * the __collapse_huge_page_copy can result in copying
+        * the old content.
+        */
+       flush_tlb_pmd_range(vma->vm_mm, &pmd, address);
        return pmd;
 }