Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fix from Al Viro:
"Braino fix for iov_iter_revert() misuse"
* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix braino in generic_file_read_iter()
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index ae82d9c..f835964 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -790,6 +790,8 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
{
if (!unroll)
return;
+ if (WARN_ON(unroll > MAX_RW_COUNT))
+ return;
i->count += unroll;
if (unlikely(i->type & ITER_PIPE)) {
struct pipe_inode_info *pipe = i->pipe;
diff --git a/mm/filemap.c b/mm/filemap.c
index b7b973b..6f1be57 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2050,7 +2050,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
iocb->ki_pos += retval;
count -= retval;
}
- iov_iter_revert(iter, iov_iter_count(iter) - count);
+ iov_iter_revert(iter, count - iov_iter_count(iter));
/*
* Btrfs can have a short DIO read if we encounter