2 files changed, 3 insertions, 1 deletions

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 60abc44385b7..fc9fb29d00eb 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 cc480c07c71b..d6e67be1802e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2048,7 +2048,7 @@ 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