iov_iter: Separate type from direction and use accessor functions
In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.
Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements. This makes it easier to add further
iterator types. Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.
Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself. Only the direction is required.
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 524ecc9..5dd433a 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -821,7 +821,7 @@ static void ceph_aio_complete_req(struct ceph_osd_request *req)
aio_req->total_len = rc + zlen;
}
- iov_iter_bvec(&i, ITER_BVEC, osd_data->bvec_pos.bvecs,
+ iov_iter_bvec(&i, READ, osd_data->bvec_pos.bvecs,
osd_data->num_bvecs,
osd_data->bvec_pos.iter.bi_size);
iov_iter_advance(&i, rc);
@@ -1044,8 +1044,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
int zlen = min_t(size_t, len - ret,
size - pos - ret);
- iov_iter_bvec(&i, ITER_BVEC, bvecs, num_pages,
- len);
+ iov_iter_bvec(&i, READ, bvecs, num_pages, len);
iov_iter_advance(&i, ret);
iov_iter_zero(zlen, &i);
ret += zlen;