[iov_iter] new privimitive: iov_iter_revert()
opposite to iov_iter_advance(); the caller is responsible for never
using it to move back past the initial position.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 804e34c..f2d36a3 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -39,7 +39,10 @@ struct iov_iter {
};
union {
unsigned long nr_segs;
- int idx;
+ struct {
+ int idx;
+ int start_idx;
+ };
};
};
@@ -81,6 +84,7 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
size_t iov_iter_copy_from_user_atomic(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes);
void iov_iter_advance(struct iov_iter *i, size_t bytes);
+void iov_iter_revert(struct iov_iter *i, size_t bytes);
int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
size_t iov_iter_single_seg_count(const struct iov_iter *i);
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,