Re: [RFC][PATCH v4 11/69] lookup_fast(): consolidate the RCU success case

Linus Torvalds
2020-03-14T00:26:11Z

On Fri, Mar 13, 2020 at 4:55 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> - if (unlikely(negative))
> + if (unlikely(!inode))
> return -ENOENT;

Isn't that buggy?

Despite the name, 'inode' isn't an inode pointer. It's a pointer to
the return location.

I think the test should be

if (unlikely(!*inode))
return -ENOENT;

and I also suspect that the argument name should be fixed (maybe
"inodepp", maybe something better).

Because the "inode" pointer itself always exists. The callers will
have something like

struct inode *inode;

and then pass in "&inode" to the function.

And it's possible that I'm talking complete garbage.

Linus