[PATCH v2] efi_driver: fix duplicate efiblk#0 issue

[Heinrich Schuchardt]

On 03.07.23 15:30, Simon Glass wrote:
> Hi Masahisa,
>
> On Mon, 3 Jul 2023 at 07:09, Masahisa Kojima <masahisa.kojima at linaro.org> wrote:
>>
>> The devnum value of the blk_desc structure starts from 0,
>> current efi_bl_create_block_device() function creates
>> two "efiblk#0" devices for the cases that blk_find_max_devnum()
>> returns -ENODEV and blk_find_max_devnum() returns 0(one device
>> found in this case).
>>
>> This commit uses blk_next_free_devnum() instead of blk_find_max_devnum().
>>

Fixes: 05ef48a2484b ("efi_driver: EFI block driver")

>> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
>> ---
>> Changes in v2:
>> - uses blk_next_free_devnum() instead of blk_find_max_devnum()
>>
>>   lib/efi_driver/efi_block_device.c | 6 ++----
>>   1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/lib/efi_driver/efi_block_device.c b/lib/efi_driver/efi_block_device.c
>> index add00eeebb..e3abd90275 100644
>> --- a/lib/efi_driver/efi_block_device.c
>> +++ b/lib/efi_driver/efi_block_device.c
>> @@ -124,10 +124,8 @@ efi_bl_create_block_device(efi_handle_t handle, void *interface)
>>          struct efi_block_io *io = interface;
>>          struct efi_blk_plat *plat;
>>
>> -       devnum = blk_find_max_devnum(UCLASS_EFI_LOADER);

Simon, this line was last changed by your patch
e33a5c6be55e ("blk: Switch over to using uclass IDs")

>> -       if (devnum == -ENODEV)
>> -               devnum = 0;
>> -       else if (devnum < 0)
>> +       devnum = blk_next_free_devnum(UCLASS_EFI_LOADER);
>
> This really should be an internal function but I see it was exported
> as part of the virtio work.
>
> How come the EFI and DM block devices are getting out of sync?

They never were in sync:

The bug dates back to Jan 2018:
05ef48a2484b ("efi_driver: EFI block driver")

Best regards

Heinrich

>
> Anyway this function is munging around in the internals of the device
> and should be fixed before it causes more problems.
>
> For now, I suggest following what most other drivers so which is to
> call blk_create_devicef() passing a devnum of -1.
>
>> +       if (devnum < 0)
>>                  return EFI_OUT_OF_RESOURCES;
>>
>>          name = calloc(1, 18); /* strlen("efiblk#2147483648") + 1 */
>> --
>> 2.34.1
>>
>
> Regards,
> Simon