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List:       linux-scsi
Subject:    Re: [ANNOUNCE] Status of unlocked_qcmds=1 operation for .37
From:       Boaz Harrosh <bharrosh () panasas ! com>
Date:       2010-10-31 12:14:28
Message-ID: 4CCD5DA4.9090806 () panasas ! com
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On 10/28/2010 08:26 PM, Andi Kleen wrote:
>> I disagree with your approach this introduces a spin_unlock_irqrestore
>> call site at every return, in the usually huge queuecommand.
> 
> I converted the full tree and in practice it turns out there 
> are very few returns in nearly all queuecommands. So it won't
> make much difference.
> 

"few returns" is too much. Any thing bigger than 1 is a total wast.

And the mess?!? Where to add the flags? where the returns? Need a 
"{...}" or not. Lots of manual intervention, and possible errors.
I bet with my approach you wouldn't need to manually fix a single
file.

> Longer term they will be all hopefully gone again anyways.
> 

That one I'm most afraid of. These that did not get fixed in this
round, will not be fixed for a long time (if ever). I'd even go
anal and not open code the lock but actually call the original
__queue_command through a MACRO, that can be change in one place.
(And will solve your patchset bisect-ability)

- XXX_queue_command(...
+ XXX_queue_command_unlocked(...


+ XXX_queue_command(...
+ {
+ 	return SCSI_LOCKED_QUEUECOMMAND(XXX_queue_command_unlocked, ...);
+ }
> -Andi

But since I'm only blabing, the one that "do", gets to decide ;-) .
Perhaps next time.

Boaz
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