Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "Cleanups that sat in -next + -stable fodder that has just missed 4.11.

  There's more iov_iter work in my local tree, but I'd prefer to push
  the stuff that had been in -next first"

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  iov_iter: don't revert iov buffer if csum error
  generic_file_read_iter(): make use of iov_iter_revert()
  generic_file_direct_write(): make use of iov_iter_revert()
  orangefs: use iov_iter_revert()
  sctp: switch to copy_from_iter_full()
  net/9p: switch to copy_from_iter_full()
  switch memcpy_from_msg() to copy_from_iter_full()
  rds: make use of iov_iter_revert()

fs/orangefs/file.c

@@ -114,7 +114,6 @@ static ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inod
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct orangefs_khandle *handle = &orangefs_inode->refn.khandle;
 	struct orangefs_kernel_op_s *new_op = NULL;
-	struct iov_iter saved = *iter;
 	int buffer_index = -1;
 	ssize_t ret;
 
@@ -193,7 +192,7 @@ static ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inod
 		orangefs_bufmap_put(buffer_index);
 		buffer_index = -1;
 		if (type == ORANGEFS_IO_WRITE)
-			*iter = saved;
+			iov_iter_revert(iter, total_size);
 		gossip_debug(GOSSIP_FILE_DEBUG,
 			     "%s:going to repopulate_shared_memory.\n",
 			     __func__);

include/linux/skbuff.h

@@ -3113,7 +3113,7 @@ struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
 
 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
 {
-	return copy_from_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
+	return copy_from_iter_full(data, len, &msg->msg_iter) ? 0 : -EFAULT;
 }
 
 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)

mm/filemap.c

@@ -2035,7 +2035,6 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 	if (iocb->ki_flags & IOCB_DIRECT) {
 		struct address_space *mapping = file->f_mapping;
 		struct inode *inode = mapping->host;
-		struct iov_iter data = *iter;
 		loff_t size;
 
 		size = i_size_read(inode);
@@ -2046,11 +2045,12 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 
 		file_accessed(file);
 
-		retval = mapping->a_ops->direct_IO(iocb, &data);
+		retval = mapping->a_ops->direct_IO(iocb, iter);
 		if (retval >= 0) {
 			iocb->ki_pos += retval;
-			iov_iter_advance(iter, retval);
+			count -= retval;
 		}
+		iov_iter_revert(iter, iov_iter_count(iter) - count);
 
 		/*
 		 * Btrfs can have a short DIO read if we encounter
@@ -2061,7 +2061,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 		 * the rest of the read.  Buffered reads will not work for
 		 * DAX files, so don't bother trying.
 		 */
-		if (retval < 0 || !iov_iter_count(iter) || iocb->ki_pos >= size ||
+		if (retval < 0 || !count || iocb->ki_pos >= size ||
 		    IS_DAX(inode))
 			goto out;
 	}
@@ -2706,7 +2706,6 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 	ssize_t		written;
 	size_t		write_len;
 	pgoff_t		end;
-	struct iov_iter data;
 
 	write_len = iov_iter_count(from);
 	end = (pos + write_len - 1) >> PAGE_SHIFT;
@@ -2735,8 +2734,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 		}
 	}
 
-	data = *from;
-	written = mapping->a_ops->direct_IO(iocb, &data);
+	written = mapping->a_ops->direct_IO(iocb, from);
 
 	/*
 	 * Finally, try again to invalidate clean pages which might have been
@@ -2753,13 +2751,14 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 
 	if (written > 0) {
 		pos += written;
-		iov_iter_advance(from, written);
+		write_len -= written;
 		if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) {
 			i_size_write(inode, pos);
 			mark_inode_dirty(inode);
 		}
 		iocb->ki_pos = pos;
 	}
+	iov_iter_revert(from, write_len - iov_iter_count(from));
 out:
 	return written;
 }

net/9p/client.c

@@ -592,9 +592,8 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
 		ename = &req->rc->sdata[req->rc->offset];
 		if (len > inline_len) {
 			/* We have error in external buffer */
-			err = copy_from_iter(ename + inline_len,
-					     len - inline_len, uidata);
-			if (err != len - inline_len) {
+			if (!copy_from_iter_full(ename + inline_len,
+					     len - inline_len, uidata)) {
 				err = -EFAULT;
 				goto out_err;
 			}

net/9p/protocol.c

@@ -74,7 +74,7 @@ pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
 {
 	size_t len = min(pdu->capacity - pdu->size, size);
 	struct iov_iter i = *from;
-	if (copy_from_iter(&pdu->sdata[pdu->size], len, &i) != len)
+	if (!copy_from_iter_full(&pdu->sdata[pdu->size], len, &i))
 		len = 0;
 
 	pdu->size += len;

net/core/datagram.c

@@ -760,7 +760,7 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb,
 
 	if (msg_data_left(msg) < chunk) {
 		if (__skb_checksum_complete(skb))
-			goto csum_error;
+			return -EINVAL;
 		if (skb_copy_datagram_msg(skb, hlen, msg, chunk))
 			goto fault;
 	} else {
@@ -768,15 +768,16 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb,
 		if (skb_copy_and_csum_datagram(skb, hlen, &msg->msg_iter,
 					       chunk, &csum))
 			goto fault;
-		if (csum_fold(csum))
-			goto csum_error;
+
+		if (csum_fold(csum)) {
+			iov_iter_revert(&msg->msg_iter, chunk);
+			return -EINVAL;
+		}
+
 		if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
 			netdev_rx_csum_fault(skb->dev);
 	}
 	return 0;
-csum_error:
-	iov_iter_revert(&msg->msg_iter, chunk);
-	return -EINVAL;
 fault:
 	return -EFAULT;
 }

net/rds/recv.c

@@ -594,7 +594,6 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 		goto out;
 
 	while (1) {
-		struct iov_iter save;
 		/* If there are pending notifications, do those - and nothing else */
 		if (!list_empty(&rs->rs_notify_queue)) {
 			ret = rds_notify_queue_get(rs, msg);
@@ -630,7 +629,6 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 		rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
 			 &inc->i_conn->c_faddr,
 			 ntohs(inc->i_hdr.h_sport));
-		save = msg->msg_iter;
 		ret = inc->i_conn->c_trans->inc_copy_to_user(inc, &msg->msg_iter);
 		if (ret < 0)
 			break;
@@ -644,7 +642,7 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 			rds_inc_put(inc);
 			inc = NULL;
 			rds_stats_inc(s_recv_deliver_raced);
-			msg->msg_iter = save;
+			iov_iter_revert(&msg->msg_iter, ret);
 			continue;
 		}
 

net/sctp/sm_make_chunk.c

@@ -1512,14 +1512,12 @@ int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
 			  struct iov_iter *from)
 {
 	void *target;
-	ssize_t copied;
 
 	/* Make room in chunk for data.  */
 	target = skb_put(chunk->skb, len);
 
 	/* Copy data (whole iovec) into chunk */
-	copied = copy_from_iter(target, len, from);
-	if (copied != len)
+	if (!copy_from_iter_full(target, len, from))
 		return -EFAULT;
 
 	/* Adjust the chunk length field.  */