Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 09cf698a authored by Al Viro's avatar Al Viro
Browse files

new primitive: iov_iter_for_each_range() 



For kvec and bvec: feeds segments to given callback as long as it
returns 0.  For iovec and pipe: fails.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6d1ff4d6

include/linux/uio.h

+4 −0
Original line number Diff line number Diff line
@@ -244,4 +244,8 @@ int compat_import_iovec(int type, const struct compat_iovec __user * uvector, 
int import_single_range(int type, void __user *buf, size_t len,

		 struct iovec *iov, struct iov_iter *i);



int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,

			    int (*f)(struct kvec *vec, void *context),

			    void *context);



#endif

lib/iov_iter.c

+22 −0
Original line number Diff line number Diff line
@@ -1446,3 +1446,25 @@ int import_single_range(int rw, void __user *buf, size_t len, 
	return 0;

}

EXPORT_SYMBOL(import_single_range);



int iov_iter_for_each_range(struct iov_iter *i, size_t bytes,

			    int (*f)(struct kvec *vec, void *context),

			    void *context)

{

	struct kvec w;

	int err = -EINVAL;

	if (!bytes)

		return 0;



	iterate_all_kinds(i, bytes, v, -EINVAL, ({

		w.iov_base = kmap(v.bv_page) + v.bv_offset;

		w.iov_len = v.bv_len;

		err = f(&w, context);

		kunmap(v.bv_page);

		err;}), ({

		w = v;

		err = f(&w, context);})

	)

	return err;

}

EXPORT_SYMBOL(iov_iter_for_each_range);