1 files changed, 24 insertions, 18 deletions

diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index 49822d90ea96..c5f734e20b0f 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -117,12 +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;
 
@@ -135,7 +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);
 
@@ -156,7 +157,7 @@ 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 {
@@ -166,30 +167,35 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 			 (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 */
@@ -198,7 +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 */
@@ -208,9 +214,9 @@ slow_irqon:
 			else
 				ret += nr;
 		}
-
-		return ret;
 	}
+
+	return ret;
 }
 
 #endif /* __HAVE_ARCH_PTE_SPECIAL */