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/9p/xattr.c b/fs/9p/xattr.c
index 352abc39e891..ac8ff8ca4c11 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -32,7 +32,7 @@ ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
 	struct iov_iter to;
 	int err;
 
-	iov_iter_kvec(&to, READ | ITER_KVEC, &kvec, 1, buffer_size);
+	iov_iter_kvec(&to, READ, &kvec, 1, buffer_size);
 
 	attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
 	if (IS_ERR(attr_fid)) {
@@ -107,7 +107,7 @@ int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
 	struct iov_iter from;
 	int retval, err;
 
-	iov_iter_kvec(&from, WRITE | ITER_KVEC, &kvec, 1, value_len);
+	iov_iter_kvec(&from, WRITE, &kvec, 1, value_len);
 
 	p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
 		 name, value_len, flags);