[PATCH] efi_driver: fix a wrong cast

[AKASHI Takahiro]

On Mon, Sep 27, 2021 at 09:48:54AM +0200, Heinrich Schuchardt wrote:
> 
> 
> On 9/27/21 6:30 AM, AKASHI Takahiro wrote:
> > struct efi_driver_binding_protocol, i.e. bp, is not the first element
> > in struct efi_driver_binding_extended_protocol.
> > So the casting:
> > 	struct efi_driver_binding_extended_protocol *bp =
> > 		(struct efi_driver_binding_extended_protocol *)this;
> > is simply wrong.
> 
> The definition in include/efi_driver.h is:
> 
> /*
>  * This structure adds internal fields to the driver binding protocol.
>  */
> struct efi_driver_binding_extended_protocol {
>         struct efi_driver_binding_protocol bp;
>         const struct efi_driver_ops *ops;
> };
> 
> Why do you claim "bp is not the first element"?
> 
> The whole efi_driver code relies on the fact that the
> efi_driver_binding_extended_protocol can be interpreted as
> efi_driver_binding_protocol.

Oops, *I* have added some member elements in another patch.
(I'm trying to make efi_driver objects show up in DM tree.)
Please forget this patch for a while.

-Takahiro Akashi

> Best regards
> 
> Heinrich
> 
> > 
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> > ---
> >   lib/efi_driver/efi_uclass.c | 14 +++++++-------
> >   1 file changed, 7 insertions(+), 7 deletions(-)
> > 
> > diff --git a/lib/efi_driver/efi_uclass.c b/lib/efi_driver/efi_uclass.c
> > index 382c2b477f4d..9e784f9c237f 100644
> > --- a/lib/efi_driver/efi_uclass.c
> > +++ b/lib/efi_driver/efi_uclass.c
> > @@ -65,8 +65,8 @@ static efi_status_t EFIAPI efi_uc_supported(
> >   {
> >   	efi_status_t r, ret;
> >   	void *interface;
> > -	struct efi_driver_binding_extended_protocol *bp =
> > -			(struct efi_driver_binding_extended_protocol *)this;
> > +	struct efi_driver_binding_extended_protocol *bp = container_of(this,
> > +			struct efi_driver_binding_extended_protocol, bp);
> > 
> >   	EFI_ENTRY("%p, %p, %ls", this, controller_handle,
> >   		  efi_dp_str(remaining_device_path));
> > @@ -113,8 +113,8 @@ static efi_status_t EFIAPI efi_uc_start(
> >   {
> >   	efi_status_t r, ret;
> >   	void *interface = NULL;
> > -	struct efi_driver_binding_extended_protocol *bp =
> > -			(struct efi_driver_binding_extended_protocol *)this;
> > +	struct efi_driver_binding_extended_protocol *bp = container_of(this,
> > +			struct efi_driver_binding_extended_protocol, bp);
> > 
> >   	EFI_ENTRY("%p, %p, %ls", this, controller_handle,
> >   		  efi_dp_str(remaining_device_path));
> > @@ -201,8 +201,8 @@ static efi_status_t EFIAPI efi_uc_stop(
> >   	efi_status_t ret;
> >   	efi_uintn_t count;
> >   	struct efi_open_protocol_info_entry *entry_buffer;
> > -	struct efi_driver_binding_extended_protocol *bp =
> > -			(struct efi_driver_binding_extended_protocol *)this;
> > +	struct efi_driver_binding_extended_protocol *bp = container_of(this,
> > +			struct efi_driver_binding_extended_protocol, bp);
> > 
> >   	EFI_ENTRY("%p, %p, %zu, %p", this, controller_handle,
> >   		  number_of_children, child_handle_buffer);
> > @@ -283,7 +283,7 @@ static efi_status_t efi_add_driver(struct driver *drv)
> >   	}
> >   	bp->bp.image_handle = bp->bp.driver_binding_handle;
> >   	ret = efi_add_protocol(bp->bp.driver_binding_handle,
> > -			       &efi_guid_driver_binding_protocol, bp);
> > +			       &efi_guid_driver_binding_protocol, &bp->bp);
> >   	if (ret != EFI_SUCCESS) {
> >   		efi_delete_handle(bp->bp.driver_binding_handle);
> >   		free(bp);
> >