linux-kernel - [PATCH 6/7] userfaultfd: report UFFDIO_ZEROPAGE as available for shmem VMAs

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Date:   Tue, 20 Jun 2017 09:20:51 +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 6/7] userfaultfd: report UFFDIO_ZEROPAGE as available for shmem VMAs

Now when shmem VMAs can be filled with zero page via userfaultfd we can
report that UFFDIO_ZEROPAGE is available for those VMAs

Signed-off-by: Mike Rapoport <rppt@...ux.vnet.ibm.com>
---
 fs/userfaultfd.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index f7555fc..57794c2 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1183,7 +1183,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 	struct uffdio_register __user *user_uffdio_register;
 	unsigned long vm_flags, new_flags;
 	bool found;
-	bool non_anon_pages;
+	bool basic_ioctls;
 	unsigned long start, end, vma_end;
 
 	user_uffdio_register = (struct uffdio_register __user *) arg;
@@ -1249,7 +1249,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 	 * Search for not compatible vmas.
 	 */
 	found = false;
-	non_anon_pages = false;
+	basic_ioctls = false;
 	for (cur = vma; cur && cur->vm_start < end; cur = cur->vm_next) {
 		cond_resched();
 
@@ -1288,8 +1288,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 		/*
 		 * Note vmas containing huge pages
 		 */
-		if (is_vm_hugetlb_page(cur) || vma_is_shmem(cur))
-			non_anon_pages = true;
+		if (is_vm_hugetlb_page(cur))
+			basic_ioctls = true;
 
 		found = true;
 	}
@@ -1360,7 +1360,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 		 * userland which ioctls methods are guaranteed to
 		 * succeed on this range.
 		 */
-		if (put_user(non_anon_pages ? UFFD_API_RANGE_IOCTLS_BASIC :
+		if (put_user(basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :
 			     UFFD_API_RANGE_IOCTLS,
 			     &user_uffdio_register->ioctls))
 			ret = -EFAULT;
-- 
2.7.4