generic_file_read_iter(): make use of iov_iter_revert()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/filemap.c b/mm/filemap.c
index 9f788ee..cc480c0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2033,7 +2033,6 @@
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);
@@ -2044,11 +2043,12 @@
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
@@ -2059,7 +2059,7 @@
* 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;
}