linux-kernel - [PATCH 4/7] userfaultfd: mcopy_atomic: introduce mfill_atomic

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Date:   Tue, 20 Jun 2017 09:20:49 +0300
From:   Mike Rapoport <rppt@...ux.vnet.ibm.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Andrea Arcangeli <aarcange@...hat.com>,
        Hugh Dickins <hughd@...gle.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Hillf Danton <hillf.zj@...baba-inc.com>,
        Pavel Emelyanov <xemul@...tuozzo.com>,
        linux mm <linux-mm@...ck.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>
Subject: [PATCH 4/7] userfaultfd: mcopy_atomic: introduce mfill_atomic_pte helper

Shuffle the code a bit to improve readability.

Signed-off-by: Mike Rapoport <rppt@...ux.vnet.ibm.com>
---
 mm/userfaultfd.c | 46 ++++++++++++++++++++++++++++++----------------
 1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 8bcb501..48c015c 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -371,6 +371,34 @@ extern ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
 				      bool zeropage);
 #endif /* CONFIG_HUGETLB_PAGE */
 
+static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
+						pmd_t *dst_pmd,
+						struct vm_area_struct *dst_vma,
+						unsigned long dst_addr,
+						unsigned long src_addr,
+						struct page **page,
+						bool zeropage)
+{
+	ssize_t err;
+
+	if (vma_is_anonymous(dst_vma)) {
+		if (!zeropage)
+			err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma,
+					       dst_addr, src_addr, page);
+		else
+			err = mfill_zeropage_pte(dst_mm, dst_pmd,
+						 dst_vma, dst_addr);
+	} else {
+		err = -EINVAL; /* if zeropage is true return -EINVAL */
+		if (likely(!zeropage))
+			err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd,
+						     dst_vma, dst_addr,
+						     src_addr, page);
+	}
+
+	return err;
+}
+
 static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
 					      unsigned long dst_start,
 					      unsigned long src_start,
@@ -487,22 +515,8 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
 		BUG_ON(pmd_none(*dst_pmd));
 		BUG_ON(pmd_trans_huge(*dst_pmd));
 
-		if (vma_is_anonymous(dst_vma)) {
-			if (!zeropage)
-				err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma,
-						       dst_addr, src_addr,
-						       &page);
-			else
-				err = mfill_zeropage_pte(dst_mm, dst_pmd,
-							 dst_vma, dst_addr);
-		} else {
-			err = -EINVAL; /* if zeropage is true return -EINVAL */
-			if (likely(!zeropage))
-				err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd,
-							     dst_vma, dst_addr,
-							     src_addr, &page);
-		}
-
+		err = mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr,
+				       src_addr, &page, zeropage);
 		cond_resched();
 
 		if (unlikely(err == -EFAULT)) {
-- 
2.7.4