Hello,
Bartlomiej Zolnierkiewicz wrote:
On Wed, 2 Feb 2005 12:06:03 +0900, Tejun Heo <[EMAIL PROTECTED]> wrote:
21_ide_do_taskfile.patch
Merged do_rw_taskfile() and flagged_taskfile() into do_taskfile(). During the merge, the following changes took place. 1. flagged taskfile now honors HOB feature register. (do_rw_taskfile() did write to HOB feature.) 2. No do_rw_taskfile() HIHI check on select register. Except for the DEV bit, all bits are honored. 3. Uses taskfile->data_phase to determine if dma trasfer is requested. (do_rw_taskfile() directly switched on taskfile->command for all dma commands)
Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>
do_rw_taskfile() is going to be used by fs requests once __ide_do_rw_disk() is converted to taskfile transport.
I don't think that do_rw_taskfile() and flagged_taskfile() merge is a good thing as it adds unnecessary overhead for hot path (fs requests).
Yeah, I also thought about that, but here are reasons why I still think merging is better.
1. The added overhead is small. It's just a dozen more if's per every disk io. I don't think it will make any noticeable difference.
2. If hot path optimization is needed, it can be easily done inside one do_taskfile() function with one or two more if's.
3. Currently, do_rw_taskfile() isn't used by __ide_do_rw_disk(). We can think about optimization when actually converting it to use taskfile transport. And IMHO, if hot path optimization is needed, leaving hot path optimization where it is now (inside __ide_do_rw_disk()) is better than moving it to separate taskfile function (do_rw_taskfile()).
-- tejun
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