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>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 52d71b64c0c6..11bcd2fb90b1 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -588,7 +588,7 @@ cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
 {
 	struct msghdr smb_msg;
 	struct kvec iov = {.iov_base = buf, .iov_len = to_read};
-	iov_iter_kvec(&smb_msg.msg_iter, READ | ITER_KVEC, &iov, 1, to_read);
+	iov_iter_kvec(&smb_msg.msg_iter, READ, &iov, 1, to_read);
 
 	return cifs_readv_from_socket(server, &smb_msg);
 }
@@ -600,7 +600,7 @@ cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
 	struct msghdr smb_msg;
 	struct bio_vec bv = {
 		.bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
-	iov_iter_bvec(&smb_msg.msg_iter, READ | ITER_BVEC, &bv, 1, to_read);
+	iov_iter_bvec(&smb_msg.msg_iter, READ, &bv, 1, to_read);
 	return cifs_readv_from_socket(server, &smb_msg);
 }