2 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/uio.h b/include/linux/uio.h
index c567655b9595..bd8569a14c4a 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -83,6 +83,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
                          struct iov_iter *i);
 size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i);
 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
+size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
 unsigned long iov_iter_alignment(const struct iov_iter *i);
 void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 88c052e63a1d..a1599ca4ab0e 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -399,6 +399,27 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 }
 EXPORT_SYMBOL(copy_from_iter);
 
+size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
+{
+        char *to = addr;
+        if (unlikely(bytes > i->count))
+                bytes = i->count;
+
+        if (unlikely(!bytes))
+                return 0;
+
+        iterate_and_advance(i, bytes, v,
+                __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
+                                         v.iov_base, v.iov_len),
+                memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
+                                 v.bv_offset, v.bv_len),
+                memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
+        )
+
+        return bytes;
+}
+EXPORT_SYMBOL(copy_from_iter_nocache);
+
 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
                          struct iov_iter *i)
 {