linux-kernel - [PATCH 3/6] mm: move VM_LOCKED check to __mlock_vma_pages

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Message-Id: <1291335412-16231-4-git-send-email-walken@google.com>
Date:	Thu,  2 Dec 2010 16:16:49 -0800
From:	Michel Lespinasse <walken@...gle.com>
To:	linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
	Hugh Dickins <hughd@...gle.com>,
	Rik van Riel <riel@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Nick Piggin <npiggin@...nel.dk>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 3/6] mm: move VM_LOCKED check to __mlock_vma_pages_range()

Use a single code path for faulting in pages during mlock.

The reason to have it in this patch series is that I did not want to
update both code paths in a later change that releases mmap_sem when
blocking on disk.

Signed-off-by: Michel Lespinasse <walken@...gle.com>
---
 mm/mlock.c |   18 +++++++++---------
 1 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 0531173..241a5d2 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -169,7 +169,7 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma,
 	VM_BUG_ON(end   > vma->vm_end);
 	VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
 
-	gup_flags = FOLL_TOUCH | FOLL_MLOCK;
+	gup_flags = FOLL_TOUCH;
 	/*
 	 * We want to touch writable mappings with a write fault in order
 	 * to break COW, except for shared mappings because these don't COW
@@ -178,6 +178,9 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma,
 	if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
 		gup_flags |= FOLL_WRITE;
 
+	if (vma->vm_flags & VM_LOCKED)
+		gup_flags |= FOLL_MLOCK;
+
 	/* We don't try to access the guard page of a stack vma */
 	if (stack_guard_page(vma, start)) {
 		addr += PAGE_SIZE;
@@ -456,14 +459,11 @@ static int do_mlock_pages(unsigned long start, size_t len)
 		/*
 		 * Now fault in a range of pages within the first VMA.
 		 */
-		if (vma->vm_flags & VM_LOCKED) {
-			ret = __mlock_vma_pages_range(vma, nstart, nend);
-			if (ret) {
-				ret = __mlock_posix_error_return(ret);
-				break;
-			}
-		} else
-			make_pages_present(nstart, nend);
+		ret = __mlock_vma_pages_range(vma, nstart, nend);
+		if (ret) {
+			ret = __mlock_posix_error_return(ret);
+			break;
+		}
 	}
 	up_read(&mm->mmap_sem);
 	return ret;	/* 0 or negative error code */
-- 
1.7.3.1

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