Re: Why flush cache in insw/outsw ?

[Paul M. <le...@li...>]

On Mon, Feb 19, 2007 at 11:38:15PM +0900, tak...@op... wrote:
> Currently, shmin can't compiled because of flush_dcache_all() in io_generic.c.
> SH3 doesn't have flush_"d"cache_all().

Ah, that's right, I forgot to stub it for SH-3.

> Could you please tell me why the flush operations has come here?
> Adding dummy flush_dcache_all() in cache_flush.h is easy, though.

We needed these for some of the IDE cases, it was something that was hit
in the PG_dcache_dirty conversion. We used to do this in the CONFIG_IDE
case by overloading the PIO I/O ops with an explicit flush, but that sort
of infrastructure no longer exists with libata. As the IDE code is really
the only user of the insw/outsw routines, this was the easy place to add
it.

You may want to add a sensible definition for SH-3 as well, but I'm not
sure how heavily you're hitting the libata drivers.