[iov_iter] new primitives - copy_from_iter_full() and friends
copy_from_iter_full(), copy_from_iter_full_nocache() and
csum_and_copy_from_iter_full() - counterparts of copy_from_iter()
et.al., advancing iterator only in case of successful full copy
and returning whether it had been successful or not.
Convert some obvious users. *NOTE* - do not blindly assume that
something is a good candidate for those unless you are sure that
not advancing iov_iter in failure case is the right thing in
this case. Anything that does short read/short write kind of
stuff (or is in a loop, etc.) is unlikely to be a good one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c6f2d89..06e8b81 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1862,8 +1862,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
i, count);
return -EINVAL;
}
- if (unlikely(copy_from_iter(&desc, sizeof(desc), &from) !=
- sizeof(desc))) {
+ if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
return -EINVAL;