Re: Patch added to scsi-rc-fixes-2.6: [SCSI] host lock push-down

[Jeff Garzik <jeff@garzik.org>]

On 11/10/2010 06:45 PM, James Bottomley wrote:
> On Wed, 2010-11-10 at 18:28 -0500, Jeff Garzik wrote:
>> On 11/10/2010 05:40 PM, James Bottomley wrote:
>>> Your commit:
>>>
>>>       [SCSI] host lock push-down
>>>
>>>       Move the mid-layer's ->queuecommand() invocation from being locked
>>>       with the host lock to being unlocked to facilitate speeding up the
>>>       critical path for drivers who don't need this lock taken anyway.
>>>
>>>       The patch below presents a simple SCSI host lock push-down as an
>>>       equivalent transformation.  No locking or other behavior should change
>>>       with this patch.  All existing bugs and locking orders are preserved.
>>>
>>>       Minimal code disturbance was attempted with this change.  Most drivers
>>>       needed only two one-line modifications for their host lock push-down.
>>>
>>>       Signed-off-by: Jeff Garzik<jgarzik@redhat.com>
>>>       Signed-off-by: James Bottomley<James.Bottomley@suse.de>
>>>
>>> has been added to the upstream SCSI tree
>>> You can find it here:
>>
>> No comments on renaming ->queuecommand to something else?
>
> What we wondered about doing differently isn't really relevant for a
> change log ... that should just really be about what was done (to avoid
> confusion).

Wasn't referring to the changelog (perhaps shouldn't have quoted that); 
just asking the question generally.


>> The consequences are rather dire if this goes unnoticed, yes?
>
> You mean if there's a missed in-tree driver?  Yes, but I took care to
> make sure all SCSI drivers were accounted for.  For out of tree drivers,
> as with the eh lock push down, it's caveat emptor.

Thinking about out-of-tree drivers, yes.

	Jeff