[PATCH v12 16/31] mm: introduce __vm_normal_page()

[Laurent Dufour]

When dealing with the speculative fault path we should use the VMA's field
cached value stored in the vm_fault structure.

Currently vm_normal_page() is using the pointer to the VMA to fetch the
vm_flags value. This patch provides a new __vm_normal_page() which is
receiving the vm_flags flags value as parameter.

Note: The speculative path is turned on for architecture providing support
for special PTE flag. So only the first block of vm_normal_page is used
during the speculative path.

Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
---
 include/linux/mm.h | 18 +++++++++++++++---
 mm/memory.c        | 21 ++++++++++++---------
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f465bb2b049e..f14b2c9ddfd4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1421,9 +1421,21 @@ static inline void INIT_VMA(struct vm_area_struct *vma)
 #endif
 }
 
-struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
-			     pte_t pte, bool with_public_device);
-#define vm_normal_page(vma, addr, pte) _vm_normal_page(vma, addr, pte, false)
+struct page *__vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+			      pte_t pte, bool with_public_device,
+			      unsigned long vma_flags);
+static inline struct page *_vm_normal_page(struct vm_area_struct *vma,
+					    unsigned long addr, pte_t pte,
+					    bool with_public_device)
+{
+	return __vm_normal_page(vma, addr, pte, with_public_device,
+				vma->vm_flags);
+}
+static inline struct page *vm_normal_page(struct vm_area_struct *vma,
+					  unsigned long addr, pte_t pte)
+{
+	return _vm_normal_page(vma, addr, pte, false);
+}
 
 struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
 				pmd_t pmd);
diff --git a/mm/memory.c b/mm/memory.c
index 85ec5ce5c0a8..be93f2c8ebe0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -533,7 +533,8 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
 }
 
 /*
- * vm_normal_page -- This function gets the "struct page" associated with a pte.
+ * __vm_normal_page -- This function gets the "struct page" associated with
+ * a pte.
  *
  * "Special" mappings do not wish to be associated with a "struct page" (either
  * it doesn't exist, or it exists but they don't want to touch it). In this
@@ -574,8 +575,9 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
  * PFNMAP mappings in order to support COWable mappings.
  *
  */
-struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
-			     pte_t pte, bool with_public_device)
+struct page *__vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+			      pte_t pte, bool with_public_device,
+			      unsigned long vma_flags)
 {
 	unsigned long pfn = pte_pfn(pte);
 
@@ -584,7 +586,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 			goto check_pfn;
 		if (vma->vm_ops && vma->vm_ops->find_special_page)
 			return vma->vm_ops->find_special_page(vma, addr);
-		if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
+		if (vma_flags & (VM_PFNMAP | VM_MIXEDMAP))
 			return NULL;
 		if (is_zero_pfn(pfn))
 			return NULL;
@@ -620,8 +622,8 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 
 	/* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */
 
-	if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
-		if (vma->vm_flags & VM_MIXEDMAP) {
+	if (unlikely(vma_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
+		if (vma_flags & VM_MIXEDMAP) {
 			if (!pfn_valid(pfn))
 				return NULL;
 			goto out;
@@ -630,7 +632,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 			off = (addr - vma->vm_start) >> PAGE_SHIFT;
 			if (pfn == vma->vm_pgoff + off)
 				return NULL;
-			if (!is_cow_mapping(vma->vm_flags))
+			if (!is_cow_mapping(vma_flags))
 				return NULL;
 		}
 	}
@@ -2532,7 +2534,8 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 
-	vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte);
+	vmf->page = __vm_normal_page(vma, vmf->address, vmf->orig_pte, false,
+				     vmf->vma_flags);
 	if (!vmf->page) {
 		/*
 		 * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a
@@ -3706,7 +3709,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
 	update_mmu_cache(vma, vmf->address, vmf->pte);
 
-	page = vm_normal_page(vma, vmf->address, pte);
+	page = __vm_normal_page(vma, vmf->address, pte, false, vmf->vma_flags);
 	if (!page) {
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
 		return 0;
-- 
2.21.0