Re: [PATCH] efi_loader: disk: allow blk devices even without UCLASS_PARTITION

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 4/28/22 06:49, AKASHI Takahiro wrote:
> While GPT partition is mandated in UEFI specification, CONFIG_PARTITION is
> seen optional under the current implementation.
> So modify efi_disk_rw_blocks() to allow accepting UCLASS_BLK devices.
>
> Fixes: commit d97e98c887ed ("efi_loader: disk: use udevice instead of blk_desc")
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
>   lib/efi_loader/efi_disk.c | 29 +++++++++++++++--------------
>   1 file changed, 15 insertions(+), 14 deletions(-)
>
> diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
> index 8fb5b2363c45..f5b462fb164a 100644
> --- a/lib/efi_loader/efi_disk.c
> +++ b/lib/efi_loader/efi_disk.c
> @@ -99,21 +99,22 @@ static efi_status_t efi_disk_rw_blocks(struct efi_block_io *this,
>   	if (buffer_size & (blksz - 1))
>   		return EFI_BAD_BUFFER_SIZE;
>
> -#if CONFIG_IS_ENABLED(PARTITIONS)
> -	if (direction == EFI_DISK_READ)
> -		n = dev_read(diskobj->dev, lba, blocks, buffer);
> -	else
> -		n = dev_write(diskobj->dev, lba, blocks, buffer);
> -#else
> -	/* dev is always a block device (UCLASS_BLK) */
> -	struct blk_desc *desc;
> +	if (CONFIG_IS_ENABLED(PARTITIONS) &&
> +	    device_get_uclass_id(diskobj->dev) == UCLASS_PARTITION) {
> +		if (direction == EFI_DISK_READ)
> +			n = dev_read(diskobj->dev, lba, blocks, buffer);
> +		else
> +			n = dev_write(diskobj->dev, lba, blocks, buffer);

Thanks for the patch. It solves the problem with the block IO protocol.

Why should dev_read() and dev_write only work for UCLASS_PARTITION?
Can't we make it work for any block device? I think the treatment of
different types of block devices should be moved to disk/disk-uclass.c.

I will pull this patch as a fast fix. But this should not be the final
design.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

> +	} else {
> +		/* dev is a block device (UCLASS_BLK) */
> +		struct blk_desc *desc;
>
> -	desc = dev_get_uclass_plat(diskobj->dev);
> -	if (direction == EFI_DISK_READ)
> -		n = blk_dread(desc, lba, blocks, buffer);
> -	else
> -		n = blk_dwrite(desc, lba, blocks, buffer);
> -#endif
> +		desc = dev_get_uclass_plat(diskobj->dev);
> +		if (direction == EFI_DISK_READ)
> +			n = blk_dread(desc, lba, blocks, buffer);
> +		else
> +			n = blk_dwrite(desc, lba, blocks, buffer);
> +	}
>
>   	/* We don't do interrupts, so check for timers cooperatively */
>   	efi_timer_check();