copy_from_iter_nocache()

BTW, do we want memcpy_nocache()?

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/include/linux/uio.h b/include/linux/uio.h
index c567655b9595dc1b9a29a21f74e0e8dedf5412aa..bd8569a14c4acadd4df6f82d67d5347504c48e47 100644 (file)
--- 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 88c052e63a1da025959f96565ffb8a8ba6a4cf88..a1599ca4ab0ed0e27917276102612d2877038b08 100644 (file)
--- 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)
 {