copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases

kmap_local_page() is enough there.  Moreover, we can use _copy_to_iter()
for actual copying in those cases - no useful extra checks on the
address we are copying from in that call.

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

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index d5f750c..8aff4eb 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -821,9 +821,9 @@ static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes
        if (likely(iter_is_iovec(i)))
                return copy_page_to_iter_iovec(page, offset, bytes, i);
        if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) {
-               void *kaddr = kmap_atomic(page);
-               size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
-               kunmap_atomic(kaddr);
+               void *kaddr = kmap_local_page(page);
+               size_t wanted = _copy_to_iter(kaddr + offset, bytes, i);
+               kunmap_local(kaddr);
                return wanted;
        }
        if (iov_iter_is_pipe(i))