Re: [RFC][PATCH] allow sleep inside EH hooks

[Jeff Garzik <jgarzik@pobox.com>]

Luben Tuikov wrote:
> On 05/27/05 04:36, Jeff Garzik wrote:
> 
>>Christoph Hellwig wrote:
>>
>>>No, hav ing the host_lock only held for ->queuecommand which doesn't
>>>need that locking doesn't make any sense.  An API like the current one
>>
>>
>>It makes a lot of sense:  LLDs are written with the assumption that 
>>paths called from ->queuecommand will not be interrupted by their own 
>>interrupt handler, whereas error handling paths are typically written 
>>with precisely the -opposite- assumption.
>>
>>Removing spin_lock_irq() from queuecommand in SCSI EH causes problems, 
>>and solves nothing.
> 
> 
> scsi_done() itself needs no explicit locking, it is completely reentrant
> and this is a good thing.
> 
> I'd like to see the same thing for queuecommand(), i.e. host_lock be gone.

We can take up that topic once I'm done with sleeping-in-EH project :)

I don't disagree...   but changing the locking for ->queuecommand() is a 
-lot- more invasive, and requires much more care.

I'm also curious to see what others think about removing the host_lock 
acquisition from ->queuecommand() calls.

	Jeff