netfs: Make netfs_advance_write() return size_t

netfs_advance_write() calculates the amount of data it's attaching to a
stream with size_t, but then returns this as an int. Switch the return
value to size_t for consistency.

Signed-off-by: David Howells <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
cc: Jeff Layton <[e-mail]>
cc: [e-mail]
cc: [e-mail]
cc: [e-mail]
Signed-off-by: Christian Brauner <[e-mail]>

fs/netfs/internal.h

···
 			 struct iov_iter *source);
 void netfs_issue_write(struct netfs_io_request *wreq,
 		       struct netfs_io_stream *stream);
-int netfs_advance_write(struct netfs_io_request *wreq,
-			struct netfs_io_stream *stream,
-			loff_t start, size_t len, bool to_eof);
+size_t netfs_advance_write(struct netfs_io_request *wreq,
+			   struct netfs_io_stream *stream,
+			   loff_t start, size_t len, bool to_eof);
 struct netfs_io_request *netfs_begin_writethrough(struct kiocb *iocb, size_t len);
 int netfs_advance_writethrough(struct netfs_io_request *wreq, struct writeback_control *wbc,
 			       struct folio *folio, size_t copied, bool to_page_end,

fs/netfs/write_issue.c

···
  * we can avoid overrunning the credits obtained (cifs) and try to parallelise
  * content-crypto preparation with network writes.
  */
-int netfs_advance_write(struct netfs_io_request *wreq,
-			struct netfs_io_stream *stream,
-			loff_t start, size_t len, bool to_eof)
+size_t netfs_advance_write(struct netfs_io_request *wreq,
+			   struct netfs_io_stream *stream,
+			   loff_t start, size_t len, bool to_eof)
 {
 	struct netfs_io_subrequest *subreq = stream->construct;
 	size_t part;