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

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