1 files changed, 36 insertions, 24 deletions

diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index 4b921af..c5f734e 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -34,7 +34,7 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
 
 	ptep = pte_offset_kernel(&pmd, addr);
 	do {
-		pte_t pte = *ptep;
+		pte_t pte = ACCESS_ONCE(*ptep);
 		struct page *page;
 
 		if ((pte_val(pte) & mask) != result)
@@ -63,12 +63,18 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
 
 	pmdp = pmd_offset(&pud, addr);
 	do {
-		pmd_t pmd = *pmdp;
+		pmd_t pmd = ACCESS_ONCE(*pmdp);
 
 		next = pmd_addr_end(addr, end);
-		if (pmd_none(pmd))
+		/*
+		 * If we find a splitting transparent hugepage we
+		 * return zero. That will result in taking the slow
+		 * path which will call wait_split_huge_page()
+		 * if the pmd is still in splitting state
+		 */
+		if (pmd_none(pmd) || pmd_trans_splitting(pmd))
 			return 0;
-		if (pmd_huge(pmd)) {
+		if (pmd_huge(pmd) || pmd_large(pmd)) {
 			if (!gup_hugepte((pte_t *)pmdp, PMD_SIZE, addr, next,
 					 write, pages, nr))
 				return 0;
@@ -91,7 +97,7 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
 
 	pudp = pud_offset(&pgd, addr);
 	do {
-		pud_t pud = *pudp;
+		pud_t pud = ACCESS_ONCE(*pudp);
 
 		next = pud_addr_end(addr, end);
 		if (pud_none(pud))
@@ -111,12 +117,13 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
 	return 1;
 }
 
-int get_user_pages_fast(unsigned long start, int nr_pages, int write,
-			struct page **pages)
+int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
+			  struct page **pages)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long addr, len, end;
 	unsigned long next;
+	unsigned long flags;
 	pgd_t *pgdp;
 	int nr = 0;
 
@@ -129,7 +136,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 
 	if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
 					start, len)))
-		goto slow_irqon;
+		return 0;
 
 	pr_devel("  aligned: %lx .. %lx\n", start, end);
 
@@ -150,40 +157,45 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 	 * So long as we atomically load page table pointers versus teardown,
 	 * we can follow the address down to the the page and take a ref on it.
 	 */
-	local_irq_disable();
+	local_irq_save(flags);
 
 	pgdp = pgd_offset(mm, addr);
 	do {
-		pgd_t pgd = *pgdp;
+		pgd_t pgd = ACCESS_ONCE(*pgdp);
 
 		pr_devel("  %016lx: normal pgd %p\n", addr,
 			 (void *)pgd_val(pgd));
 		next = pgd_addr_end(addr, end);
 		if (pgd_none(pgd))
-			goto slow;
+			break;
 		if (pgd_huge(pgd)) {
 			if (!gup_hugepte((pte_t *)pgdp, PGDIR_SIZE, addr, next,
 					 write, pages, &nr))
-				goto slow;
+				break;
 		} else if (is_hugepd(pgdp)) {
 			if (!gup_hugepd((hugepd_t *)pgdp, PGDIR_SHIFT,
 					addr, next, write, pages, &nr))
-				goto slow;
+				break;
 		} else if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
-			goto slow;
+			break;
 	} while (pgdp++, addr = next, addr != end);
 
-	local_irq_enable();
+	local_irq_restore(flags);
 
-	VM_BUG_ON(nr != (end - start) >> PAGE_SHIFT);
 	return nr;
+}
 
-	{
-		int ret;
+int get_user_pages_fast(unsigned long start, int nr_pages, int write,
+			struct page **pages)
+{
+	struct mm_struct *mm = current->mm;
+	int nr, ret;
+
+	start &= PAGE_MASK;
+	nr = __get_user_pages_fast(start, nr_pages, write, pages);
+	ret = nr;
 
-slow:
-		local_irq_enable();
-slow_irqon:
+	if (nr < nr_pages) {
 		pr_devel("  slow path ! nr = %d\n", nr);
 
 		/* Try to get the remaining pages with get_user_pages */
@@ -192,7 +204,7 @@ slow_irqon:
 
 		down_read(&mm->mmap_sem);
 		ret = get_user_pages(current, mm, start,
-			(end - start) >> PAGE_SHIFT, write, 0, pages, NULL);
+				     nr_pages - nr, write, 0, pages, NULL);
 		up_read(&mm->mmap_sem);
 
 		/* Have to be a bit careful with return values */
@@ -202,9 +214,9 @@ slow_irqon:
 			else
 				ret += nr;
 		}
-
-		return ret;
 	}
+
+	return ret;
 }
 
 #endif /* __HAVE_ARCH_PTE_SPECIAL */