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()

1 files changed, 7 insertions, 8 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index c5808b7..dc59c5f 100644
--- a/mm/filemap.c
+++ b/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;
 }