Re: [PATCH 2.6.11-rc2] ide: merge do_rw_taskfile() and flagged_taskfile() into do_taskfile()

[Tejun Heo <tj@home-tj.org>]

Hello,

Bartlomiej Zolnierkiewicz wrote:
> On Sun, 6 Feb 2005 11:13:31 +0900, Tejun Heo <tj@home-tj.org> wrote:
> 
>> Hello, Bartlomiej.
> 
> 
> Hi,
> 
> 
>> This is a new version of ide_do_taskfile.patch.  Compared to the
>>original do_rw_task(), only one more 'if' is used in the hot path, so
>>I think the performance issue can be ignored now.  Also, there's no
>>userland visible change with this patch.  Everything should work just
>>as it did with do_rw_taskfile()/flagged_taskfile().
>>
>> do_taskfile() is different from do_rw_taskfile() in that
> 
> 
> Is there any gain in changing name to do_taskfile()?
>  

  Well, I was just thinking

  do_rw_taskfile + (do_)flagged_taskfile -> do_taskfile.

  If you like do_rw_taskfile better, I guess that's okay too. :-)

> 
>> - It uses task->data_phase to determine whether it's a DMA command
>>   or not.
> 
> 
> this is user-space visible change
> (it is right thing to do, I just wanted to point the fact)
> 

  Oops, I forgot that.  Still, it was kind of weird before.  If any of 
tf_{in|out}_flags is set, flagged_taskfile() is called and ->data_phase 
was used, but, if none of the flags was set, do_rw_taskfile() was called 
and the command is used to determine the same thing.  But, yeah, it's 
user-visible.

> 
>> do_taskfile() is different from flagged_taskfile() in that
>>
>> - No (TASKFILE_MULTI_IN && !mult_count) check.  ide_taskfile_ioctl()
>>   checks the same thing, so it doesn't change anything.
> 
> 
> The check may be needed.  AFAIR drive->mult_count may change
> before our taskfile request is started.
> 

  Okay, I'll resurrect that test.

> 
>> - No task->tf_out_flags handling.  ide_end_drive_cmd() ignores it
>>   anyway, so, again, it doesn't change anything.
> 
> 
> I guess you mean ->tf_in_flags?
> 

  Yes.

> 
>> So, what do you think?
> 
> 
> This patch looks much better but could you move writing taskfile
> registers to separate helpers (one for non-flagged and one for flagged)?
> 
> Probably splitting non-flagged taskfile load helper off do_rw_taskfile()
> should be done in separate patch.  We can then use this helper in
> ide-disk.c for __ide_do_rw_taskfile() (we can't do direct conversion
> to do_rw_taskfile() yet for various reasons).

  Sure, I'll do it now.

  Thanks.

-- 
tejun