[PATCH 16/26] mm: Provide get_user_pages_unlocked()

[Jan Kara]

Provide a wrapper for get_user_pages() which takes care of acquiring and
releasing mmap_sem. Using this function reduces amount of places in
which we deal with mmap_sem.

Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 include/linux/mm.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8b6e55ee8855..70031ead06a5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1031,6 +1031,20 @@ long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 		    struct vm_area_struct **vmas);
 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 			struct page **pages);
+static inline long
+get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
+		 	unsigned long start, unsigned long nr_pages,
+			int write, int force, struct page **pages)
+{
+	long ret;
+
+	down_read(&mm->mmap_sem);
+	ret = get_user_pages(tsk, mm, start, nr_pages, write, force, pages,
+			     NULL);
+	up_read(&mm->mmap_sem);
+	return ret;
+}
+
 struct kvec;
 int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
 			struct page **pages);
-- 
1.8.1.4

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