Re: [PATCH] Revert "block: WARN in __blk_put_request() for potential bio leak"

[Boaz Harrosh <bharrosh@panasas.com>]

On 06/10/2009 11:29 AM, FUJITA Tomonori wrote:
> On Wed, 10 Jun 2009 11:15:10 +0300
> Boaz Harrosh <bharrosh@panasas.com> wrote:
>> That is a violation of block API. All block drivers must call
>> blk_end_request().
> 
> Where can I find a documentation about it?
> 

No documentation

> If not, can you stop claiming a new rule?
> 

The fact that ALL block drivers call it for proper service of ALL ULDS,
does it not make it a rule?

> If you want to propose a new rule, you need to fix the existing users
> first.
> 

Sorry I missed them. I couldn't even imagine that there will be any.
Will send patches, sorry.

> 
>> If they do not, then they can not for example be
>> called from inside Kernel. They relay on special bsg behavior
>> that always uses map_user.
> 
> Of course, we send SMP requests only via BSG. SMP is the first reason
> why we invented BSG.
> 

Of course what? Show me the big fat comment that says:
  only use from BSG!!! other wise broken block driver.

> 
<snip>
> 
> You don't need SAS hardware to play with blk_rq_map_user() and
> blk_rq_unmap_user(). All you need to do is writing a module that play
> with these functions.
> 
> 
>> I do believe you that there is no leak, I just want to understand why?
>> And any way, all "BSG SMP" drivers must be fixed to call blk_end_request().
>> They can not be dependent on the specific ULD that calls them.

Boaz