From aa563d7bca6e882ec2bdae24603c8f016401a144 Mon Sep 17 00:00:00 2001 From: David Howells Date: Sat, 20 Oct 2018 00:57:56 +0100 Subject: 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 --- drivers/xen/pvcalls-back.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index b1092fbefa63..2e5d845b5091 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -137,13 +137,13 @@ static void pvcalls_conn_back_read(void *opaque) if (masked_prod < masked_cons) { vec[0].iov_base = data->in + masked_prod; vec[0].iov_len = wanted; - iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 1, wanted); + iov_iter_kvec(&msg.msg_iter, WRITE, vec, 1, wanted); } else { vec[0].iov_base = data->in + masked_prod; vec[0].iov_len = array_size - masked_prod; vec[1].iov_base = data->in; vec[1].iov_len = wanted - vec[0].iov_len; - iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 2, wanted); + iov_iter_kvec(&msg.msg_iter, WRITE, vec, 2, wanted); } atomic_set(&map->read, 0); @@ -195,13 +195,13 @@ static void pvcalls_conn_back_write(struct sock_mapping *map) if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) { vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); vec[0].iov_len = size; - iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 1, size); + iov_iter_kvec(&msg.msg_iter, READ, vec, 1, size); } else { vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); vec[0].iov_len = array_size - pvcalls_mask(cons, array_size); vec[1].iov_base = data->out; vec[1].iov_len = size - vec[0].iov_len; - iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 2, size); + iov_iter_kvec(&msg.msg_iter, READ, vec, 2, size); } atomic_set(&map->write, 0); -- cgit v1.2.3