Re: [RESEND v9 1/9] efi_loader: move udevice pointer into struct efi_object

[Takahiro Akashi <takahiro.akashi@linaro.org>]

On Wed, Jul 20, 2022 at 09:44:43AM +0200, Heinrich Schuchardt wrote:
> On 7/20/22 01:56, Takahiro Akashi wrote:
> > On Sun, Jul 17, 2022 at 10:09:42AM +0200, Heinrich Schuchardt wrote:
> > > On 7/15/22 16:47, Masahisa Kojima wrote:
> > > > This is a preparation patch to provide the unified method
> > > > to access udevice pointer associated with the block io device.
> > > > The EFI handles of both EFI block io driver implemented in
> > > > lib/efi_loader/efi_disk.c and EFI block io driver implemented
> > > > as EFI payload can posess the udevice pointer in the struct efi_object.
> > > > 
> > > > We can use this udevice pointer to get the U-Boot friendly
> > > > block device name(e.g. mmc 0:1, nvme 0:1) through efi_handle_t.
> > > > 
> > > > Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
> > > > ---
> > > > Newly created in v9
> > > > 
> > > >    include/efi_loader.h      |  8 ++++++++
> > > >    lib/efi_loader/efi_disk.c | 20 +++++++++++++-------
> > > >    2 files changed, 21 insertions(+), 7 deletions(-)
> > > > 
> > > > diff --git a/include/efi_loader.h b/include/efi_loader.h
> > > > index 3a63a1f75f..bba5ffd482 100644
> > > > --- a/include/efi_loader.h
> > > > +++ b/include/efi_loader.h
> > > > @@ -226,6 +226,12 @@ const char *__efi_nesting_dec(void);
> > > >    #define EFI_CACHELINE_SIZE 128
> > > >    #endif
> > > > 
> > > > +/**
> > > > + * efi_handle_to_udev - accessor to the DM device associated to the EFI handle
> > > > + * @handle:	pointer to the EFI handle
> > > > + */
> > > > +#define efi_handle_to_udev(handle) (((struct efi_object *)handle)->dev)
> > > 
> > > This conversion will hide errors if handle is not of type efi_handle_t.
> > > We should avoid the conversion and see build time errors instead.
> > > Please, remove the macro.
> > 
> > I don't think we should remove the macro itself, but only the type casting.
> > 
> > I think it is a good practice to hide an implementation how the relationship
> > between udev and efi_object is maintained *behind* accessor macros.
> > 
> > > For every handle of type efi_handle_t you can access the field
> > > handle->dev directly.
> > > 
> > > For struct efi_disk_obj we can use disk->header.dev.
> > 
> > This is a good example for hiding the implementation from the rest of code.
> 
> Such a macro is pure code obfuscation.

I don't think so. It will help make it easier to read the code.

If I follow your logic, why did you introduce/accept guidcpy/guidcmp()?

-Takahiro Akashi

> I won't take such a patch.
> 
> Best regards
> 
> Heinrich
> 
> > 
> > > > +
> > > >    /* Key identifying current memory map */
> > > >    extern efi_uintn_t efi_memory_map_key;
> > > > 
> > > > @@ -375,6 +381,7 @@ enum efi_object_type {
> > > >     * @protocols:	linked list with the protocol interfaces installed on this
> > > >     *		handle
> > > >     * @type:	image type if the handle relates to an image
> > > > + * @dev:	pointer to the DM device which is associated with this EFI handle
> > > >     *
> > > >     * UEFI offers a flexible and expandable object model. The objects in the UEFI
> > > >     * API are devices, drivers, and loaded images. struct efi_object is our storage
> > > > @@ -392,6 +399,7 @@ struct efi_object {
> > > >    	/* The list of protocols */
> > > >    	struct list_head protocols;
> > > >    	enum efi_object_type type;
> > > > +	struct udevice *dev;
> > > >    };
> > > > 
> > > >    enum efi_image_auth_status {
> > > > diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
> > > > index 1d700b2a6b..a8e8521e3e 100644
> > > > --- a/lib/efi_loader/efi_disk.c
> > > > +++ b/lib/efi_loader/efi_disk.c
> > > > @@ -46,7 +46,6 @@ struct efi_disk_obj {
> > > >    	struct efi_device_path *dp;
> > > >    	unsigned int part;
> > > >    	struct efi_simple_file_system_protocol *volume;
> > > > -	struct udevice *dev; /* TODO: move it to efi_object */
> > > 
> > > ok
> > > 
> > > >    };
> > > > 
> > > >    /**
> > > > @@ -124,16 +123,16 @@ static efi_status_t efi_disk_rw_blocks(struct efi_block_io *this,
> > > >    		return EFI_BAD_BUFFER_SIZE;
> > > > 
> > > >    	if (CONFIG_IS_ENABLED(PARTITIONS) &&
> > > > -	    device_get_uclass_id(diskobj->dev) == UCLASS_PARTITION) {
> > > > +	    device_get_uclass_id(efi_handle_to_udev(diskobj)) == UCLASS_PARTITION) {
> > > 
> > > device_get_uclass_id(diskobj->header.hdev)) == UCLASS_PARTITION) {
> > > 
> > > >    		if (direction == EFI_DISK_READ)
> > > > -			n = dev_read(diskobj->dev, lba, blocks, buffer);
> > > > +			n = dev_read(efi_handle_to_udev(diskobj), lba, blocks, buffer);
> > > 
> > > dev_read(diskobj->header.hdev)
> > > 
> > > >    		else
> > > > -			n = dev_write(diskobj->dev, lba, blocks, buffer);
> > > > +			n = dev_write(efi_handle_to_udev(diskobj), lba, blocks, buffer);
> > > 
> > > dev_write(diskobj->header.hdev)
> > > 
> > > >    	} else {
> > > >    		/* dev is a block device (UCLASS_BLK) */
> > > >    		struct blk_desc *desc;
> > > > 
> > > > -		desc = dev_get_uclass_plat(diskobj->dev);
> > > > +		desc = dev_get_uclass_plat(efi_handle_to_udev(diskobj));
> > > 
> > > dev_get_uclass(diskobj->header.hdev)
> > > 
> > > 
> > > >    		if (direction == EFI_DISK_READ)
> > > >    			n = blk_dread(desc, lba, blocks, buffer);
> > > >    		else
> > > > @@ -552,7 +551,7 @@ static int efi_disk_create_raw(struct udevice *dev)
> > > > 
> > > >    		return -1;
> > > >    	}
> > > > -	disk->dev = dev;
> > > > +	efi_handle_to_udev(disk) = dev;
> > > >    	if (dev_tag_set_ptr(dev, DM_TAG_EFI, &disk->header)) {
> > > >    		efi_free_pool(disk->dp);
> > > >    		efi_delete_handle(&disk->header);
> > > > @@ -609,7 +608,7 @@ static int efi_disk_create_part(struct udevice *dev)
> > > >    		log_err("Adding partition for %s failed\n", dev->name);
> > > >    		return -1;
> > > >    	}
> > > > -	disk->dev = dev;
> > > > +	efi_handle_to_udev(disk) = dev;
> > > 
> > > disk->header.dev = dev;
> > 
> > It's my preference, but I would suggest another accessor:
> >         efi_set_udev(handle, dev);
> > to hide an implementation.
> > 
> > -Takahiro Akashi
> > 
> > > 
> > > >    	if (dev_tag_set_ptr(dev, DM_TAG_EFI, &disk->header)) {
> > > >    		efi_free_pool(disk->dp);
> > > >    		efi_delete_handle(&disk->header);
> > > > @@ -656,6 +655,13 @@ static int efi_disk_probe(void *ctx, struct event *event)
> > > >    		ret = efi_disk_create_raw(dev);
> > > >    		if (ret)
> > > >    			return -1;
> > > > +	} else {
> > > > +		efi_handle_t handle;
> > > > +
> > > > +		if (dev_tag_get_ptr(dev, DM_TAG_EFI, (void **)&handle))
> > > > +			return -1;
> > > > +
> > > > +		efi_handle_to_udev(handle) = dev;
> > > 
> > > handle->dev = dev;
> > > 
> > > Best regards
> > > 
> > > Heinrich
> > > 
> > > >    	}
> > > > 
> > > >    	device_foreach_child(child, dev) {
> > > 
>