# Re: \[PATCH v2 02/26\] block: Add bio\_advance()

- From: Tejun Heo \<hidden\>
- Date: 2012-09-20 23:25:13 
- List: linux-bcache
- Page: https://ratatoskr.run/linux-bcache/2012/09/3926542
- Thread: https://ratatoskr.run/linux-bcache/2012/09/3920950/t.md

```text
Hello,

On Thu, Sep 20, 2012 at 04:13:08PM -0700, Kent Overstreet wrote:
> I just cut and pasted that from blk_update_request(), which is what the
> next patch refactors...

Yeah, well, that was written when we didn't have WARNs.

> But yes it would be a bug. It gets converted to a BUG_ON() in a later
> patch (not in this series), as this gets further abstracted into a
> wrapper around bvec_advance_iter() which doesn't know about struct bio
> (as bio integrity gets its own iterator).

WARN() generally preferable unless there's no way at all to continue.
Storage layer could be a bit different if immediate danger for data
corruption exists but the general consensus seems that we're too
trigger happy with BUG_ON()s.

Thanks.

-- 
tejun
```