Re: [SeaBIOS] Wrong address returned by container _of macro

[Kevin O'Connor]

On Wed, Apr 04, 2012 at 04:04:54PM +0900, Daniel Castro wrote:
> Hello All,
>
> I have a little problem, when I try to get my drive on boot (16bit) I
> am getting the wrong address:
>
> This code:
>   struct xendrive_s * xendrive =
> GLOBALFLAT2GLOBAL(container_of(GET_GLOBAL(op->drive_g), struct
> xendrive_s, drive));

op is on the stack, so one must not use GET_GLOBAL on it.  Also,
drive_g is already a "global", so GLOBALFLAT2GLOBAL must not be called
on it.  So, this should read:

struct xendrive_s * xendrive = container_of(op->drive_g, struct xendrive_s, drive))

If one looks at the other disk drivers, they'll see something similar
- for example ahci_cmd_data() has:

    struct ahci_port_s *port = container_of(
        op->drive_g, struct ahci_port_s, drive);

-Kevin

Wrong address returned by container _of macro

[Daniel Castro]

On Fri, Apr 6, 2012 at 9:57 PM, Kevin O'Connor <[e-mail]> wrote:
> On Wed, Apr 04, 2012 at 04:04:54PM +0900, Daniel Castro wrote:
> > Hello All,
> >
> > I have a little problem, when I try to get my drive on boot (16bit) I
> > am getting the wrong address:
> >
> > This code:
> >       struct xendrive_s * xendrive =
> > GLOBALFLAT2GLOBAL(container_of(GET_GLOBAL(op->drive_g), struct
> > xendrive_s, drive));
>
> op is on the stack, so one must not use GET_GLOBAL on it.  Also,
> drive_g is already a "global", so GLOBALFLAT2GLOBAL must not be called
> on it.  So, this should read:
>
> struct xendrive_s * xendrive = container_of(op->drive_g, struct xendrive_s, drive))
>
> If one looks at the other disk drivers, they'll see something similar
> - for example ahci_cmd_data() has:
>
>    struct ahci_port_s *port = container_of(
>        op->drive_g, struct ahci_port_s, drive);
> Yes, indeed, I followed the same process as virtuo drivers, yet the
> memory address returned by container_of made no sense, so I kept
> trying stuff out. Anyway I have a work around now, maybe later when I
> clean the code I will change it back to just container_of, I am
> pushing forward to get a working prototype as soon as possible.
> -Kevin