Hello, Mark.
On Tue, Jun 04, 2013 at 10:09:41AM -0500, Mark Langsdorf wrote:
> > And tell ahci core sizeof(ecx_host_priv) some way, but really, just
> > having a plain pointer should be enough, I think.
>
> I think I want to do the opposite. For 90% of the AHCI EM functions,
> I want ecx_host_priv to be an ahci_host_priv so that I can use those
> functions without having to keep a local copy of them.
>
> Would something like this:
> struct ahci_host_priv {
> /* standard AHCI existing stuff */
> void *private_data;
> };
>
> I shied away from that because a private data structure having a private
> data structure doesn't seem right.
Aren't we talking about the same thing? I'm perfectly fine with
adding a pointer to ahci_host_priv. Maybe you can name it slightly
differently - say, *impl_data, *platform_data, whatever.
> >> +static ssize_t ecx_transmit_led_message(struct ata_port *ap, u32 state,
> >> + ssize_t size)
> >> +{
> > ...
> >> + if (!hpriv->em_msg_type & EM_MSG_TYPE_LED)
> >> + return size;
> >
> > Is this really correct? You first negate and convert it to bool and
> > then bit-wise and it with a mask? How is supposed to work?
>
> Am I confused about the order of operations? It's meant to be "continue
> if hpriv->em_msg_type doesn't have EM_MSG_TYPE_LED set".
Shouldn't that be
if (!(hpriv->em_msg_type & EM_MSG_TYPE_LED))
! has higher priority than &. You're converting em_msg_type to 1 or 0
and then and'ing EM_MSG_TYPE_LED to it.
> >> - ahci_save_initial_config(dev, hpriv, 0, 0);
> >> + ahci_save_initial_config(dev, (struct ahci_host_priv *) hpriv, 0, 0);
> >
> > Ugh....... how is this supposed to work? What if ahci_host_priv grows
> > larger than ecx one in the future? :(
>
> For functions like ahci_save_initial_config, I just want to use the
> already defined ahci_ functions with my extra data along for the ride.
> What's the best way to do that?
Please don't override different types on the same area. Having the
driver specific data in a separate struct pointed to by ahci_host_priv
should work fine, right?
Thanks.
--
tejun
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