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>

14 files changed, 30 insertions, 35 deletions

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index e1cbdfdb7c68..0bcbcc20f769 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -65,7 +65,7 @@ static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
 	if (retval == 0)
 		return retval;
 
-	iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE);
+	iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
 
 	retval = p9_client_read(fid, page_offset(page), &to, &err);
 	if (err) {
@@ -175,7 +175,7 @@ static int v9fs_vfs_writepage_locked(struct page *page)
 	bvec.bv_page = page;
 	bvec.bv_offset = 0;
 	bvec.bv_len = len;
-	iov_iter_bvec(&from, ITER_BVEC | WRITE, &bvec, 1, len);
+	iov_iter_bvec(&from, WRITE, &bvec, 1, len);
 
 	/* We should have writeback_fid always set */
 	BUG_ON(!v9inode->writeback_fid);
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index b0405d6aac85..d5db3c968a03 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -133,7 +133,7 @@ static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
 		if (rdir->tail == rdir->head) {
 			struct iov_iter to;
 			int n;
-			iov_iter_kvec(&to, READ | ITER_KVEC, &kvec, 1, buflen);
+			iov_iter_kvec(&to, READ, &kvec, 1, buflen);
 			n = p9_client_read(file->private_data, ctx->pos, &to,
 					   &err);
 			if (err)
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);
diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 77a83790a31f..639c16882e93 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -286,7 +286,7 @@ static void afs_load_bvec(struct afs_call *call, struct msghdr *msg,
 		offset = 0;
 	}
 
-	iov_iter_bvec(&msg->msg_iter, WRITE | ITER_BVEC, bv, nr, bytes);
+	iov_iter_bvec(&msg->msg_iter, WRITE, bv, nr, bytes);
 }
 
 /*
@@ -401,8 +401,7 @@ long afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call,
 
 	msg.msg_name		= NULL;
 	msg.msg_namelen		= 0;
-	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
-		      call->request_size);
+	iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, call->request_size);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= MSG_WAITALL | (call->send_pages ? MSG_MORE : 0);
@@ -432,7 +431,7 @@ error_do_abort:
 		rxrpc_kernel_abort_call(call->net->socket, rxcall,
 					RX_USER_ABORT, ret, "KSD");
 	} else {
-		iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, NULL, 0, 0);
+		iov_iter_kvec(&msg.msg_iter, READ, NULL, 0, 0);
 		rxrpc_kernel_recv_data(call->net->socket, rxcall,
 				       &msg.msg_iter, false,
 				       &call->abort_code, &call->service_id);
@@ -468,7 +467,7 @@ static void afs_deliver_to_call(struct afs_call *call)
 		if (state == AFS_CALL_SV_AWAIT_ACK) {
 			struct iov_iter iter;
 
-			iov_iter_kvec(&iter, READ | ITER_KVEC, NULL, 0, 0);
+			iov_iter_kvec(&iter, READ, NULL, 0, 0);
 			ret = rxrpc_kernel_recv_data(call->net->socket,
 						     call->rxcall, &iter, false,
 						     &remote_abort,
@@ -825,7 +824,7 @@ void afs_send_empty_reply(struct afs_call *call)
 
 	msg.msg_name		= NULL;
 	msg.msg_namelen		= 0;
-	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
+	iov_iter_kvec(&msg.msg_iter, WRITE, NULL, 0, 0);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;
@@ -864,7 +863,7 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 	iov[0].iov_len		= len;
 	msg.msg_name		= NULL;
 	msg.msg_namelen		= 0;
-	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
+	iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;
@@ -905,7 +904,7 @@ int afs_extract_data(struct afs_call *call, void *buf, size_t count,
 
 	iov.iov_base = buf + call->offset;
 	iov.iov_len = count - call->offset;
-	iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, count - call->offset);
+	iov_iter_kvec(&iter, READ, &iov, 1, count - call->offset);
 
 	ret = rxrpc_kernel_recv_data(net->socket, call->rxcall, &iter,
 				     want_more, &remote_abort,
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 524ecc95b04d..5dd433aa9b23 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;
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);
 }
 
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 7b5b960a04b8..10cff44832d8 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -857,7 +857,7 @@ setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 	ctx->bv = bv;
 	ctx->len = saved_len - count;
 	ctx->npages = npages;
-	iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
+	iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
 	return 0;
 }
 
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 89985a0a6819..26f8a65b8722 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2962,13 +2962,13 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 			return 0;
 		}
 
-		iov_iter_bvec(&iter, WRITE | ITER_BVEC, bvec, npages, data_len);
+		iov_iter_bvec(&iter, WRITE, bvec, npages, data_len);
 	} else if (buf_len >= data_offset + data_len) {
 		/* read response payload is in buf */
 		WARN_ONCE(npages > 0, "read data can be either in buf or in pages");
 		iov.iov_base = buf + data_offset;
 		iov.iov_len = data_len;
-		iov_iter_kvec(&iter, WRITE | ITER_KVEC, &iov, 1, data_len);
+		iov_iter_kvec(&iter, WRITE, &iov, 1, data_len);
 	} else {
 		/* read response payload cannot be in both buf and pages */
 		WARN_ONCE(1, "buf can not contain only a part of read data");
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index b48f43963da6..146b618802a5 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -307,8 +307,7 @@ __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 			.iov_base = &rfc1002_marker,
 			.iov_len  = 4
 		};
-		iov_iter_kvec(&smb_msg.msg_iter, WRITE | ITER_KVEC, &hiov,
-			      1, 4);
+		iov_iter_kvec(&smb_msg.msg_iter, WRITE, &hiov, 1, 4);
 		rc = smb_send_kvec(server, &smb_msg, &sent);
 		if (rc < 0)
 			goto uncork;
@@ -329,8 +328,7 @@ __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 			size += iov[i].iov_len;
 		}
 
-		iov_iter_kvec(&smb_msg.msg_iter, WRITE | ITER_KVEC,
-			      iov, n_vec, size);
+		iov_iter_kvec(&smb_msg.msg_iter, WRITE, iov, n_vec, size);
 
 		rc = smb_send_kvec(server, &smb_msg, &sent);
 		if (rc < 0)
@@ -346,7 +344,7 @@ __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 			rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
 					     &bvec.bv_offset);
 
-			iov_iter_bvec(&smb_msg.msg_iter, WRITE | ITER_BVEC,
+			iov_iter_bvec(&smb_msg.msg_iter, WRITE,
 				      &bvec, 1, bvec.bv_len);
 			rc = smb_send_kvec(server, &smb_msg, &sent);
 			if (rc < 0)
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index a5e4a221435c..76976d6e50f9 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -674,7 +674,7 @@ static int receive_from_sock(struct connection *con)
 		nvec = 2;
 	}
 	len = iov[0].iov_len + iov[1].iov_len;
-	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, iov, nvec, len);
+	iov_iter_kvec(&msg.msg_iter, READ, iov, nvec, len);
 
 	r = ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
 	if (ret <= 0)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index b53e76391e52..8b90f5480904 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -923,7 +923,7 @@ __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	int host_err;
 
 	trace_nfsd_read_vector(rqstp, fhp, offset, *count);
-	iov_iter_kvec(&iter, READ | ITER_KVEC, vec, vlen, *count);
+	iov_iter_kvec(&iter, READ, vec, vlen, *count);
 	host_err = vfs_iter_read(file, &iter, &offset, 0);
 	return nfsd_finish_read(rqstp, fhp, file, offset, count, host_err);
 }
@@ -999,7 +999,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	if (stable && !use_wgather)
 		flags |= RWF_SYNC;
 
-	iov_iter_kvec(&iter, WRITE | ITER_KVEC, vec, vlen, *cnt);
+	iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
 	host_err = vfs_iter_write(file, &iter, &pos, flags);
 	if (host_err < 0)
 		goto out_nfserr;
diff --git a/fs/ocfs2/cluster/tcp.c b/fs/ocfs2/cluster/tcp.c
index 7d9eea7d4a87..e9f236af1927 100644
--- a/fs/ocfs2/cluster/tcp.c
+++ b/fs/ocfs2/cluster/tcp.c
@@ -916,7 +916,7 @@ static int o2net_recv_tcp_msg(struct socket *sock, void *data, size_t len)
 {
 	struct kvec vec = { .iov_len = len, .iov_base = data, };
 	struct msghdr msg = { .msg_flags = MSG_DONTWAIT, };
-	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &vec, 1, len);
+	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, len);
 	return sock_recvmsg(sock, &msg, MSG_DONTWAIT);
 }
 
diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
index 31932879b716..136a8bdc1d91 100644
--- a/fs/orangefs/inode.c
+++ b/fs/orangefs/inode.c
@@ -25,7 +25,7 @@ static int read_one_page(struct page *page)
 	struct iov_iter to;
 	struct bio_vec bv = {.bv_page = page, .bv_len = PAGE_SIZE};
 
-	iov_iter_bvec(&to, ITER_BVEC | READ, &bv, 1, PAGE_SIZE);
+	iov_iter_bvec(&to, READ, &bv, 1, PAGE_SIZE);
 
 	gossip_debug(GOSSIP_INODE_DEBUG,
 		    "orangefs_readpage called with page %p\n",
diff --git a/fs/splice.c b/fs/splice.c
index b3daa971f597..3553f1956508 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -301,7 +301,7 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
 	struct kiocb kiocb;
 	int idx, ret;
 
-	iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len);
+	iov_iter_pipe(&to, READ, pipe, len);
 	idx = to.idx;
 	init_sync_kiocb(&kiocb, in);
 	kiocb.ki_pos = *ppos;
@@ -386,7 +386,7 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
 	 */
 	offset = *ppos & ~PAGE_MASK;
 
-	iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len + offset);
+	iov_iter_pipe(&to, READ, pipe, len + offset);
 
 	res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &base);
 	if (res <= 0)
@@ -745,8 +745,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 			left -= this_len;
 		}
 
-		iov_iter_bvec(&from, ITER_BVEC | WRITE, array, n,
-			      sd.total_len - left);
+		iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left);
 		ret = vfs_iter_write(out, &from, &sd.pos, 0);
 		if (ret <= 0)
 			break;