[PATCH] part: return -ENOSYS when get_info not valid.

[Heinrich Schuchardt]

On 10/20/21 04:37, schspa wrote:
> 在 2021-10-19星期二的 17:23 +0200，Heinrich Schuchardt写道：
>> On 10/19/21 15:35, zhaohui.shi wrote:
>>> From: schspa <schspa at gmail.com>
>>>
>>> In some case, get_info() interface can be NULL, add this check to
>>> stop
>>> from crash.
>>
>> Thank you for reviewing the partition driver code.
>>
>> There seems to be no driver missing a get_info implementation. Where
>> did
>> you run into a problem?
>>
> Yes, I do run into a problem, In my spl build, CONFIG_SPL_FS_EXT4,
> CONFIG_SPL_FS_FAT, CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION are all
> not enabled. In this case, get_info implementation is NULL. see
> 'part_get_info_ptr' and 'part_print_ptr' and part_efi.c for detail.
>
>> Why should we only check .get_info and not .test and not .print?
>>
>
> All part type driver have .test implementation, it can't be NULL,
> and .print have NULL pointer judgement already.
>
>>>
>>> Signed-off-by: schspa <schspa at gmail.com>
>>
>> Please, provide a name.
>>
>>> ---
>>>    disk/part.c | 7 +++++++
>>>    1 file changed, 7 insertions(+)
>>>
>>> diff --git a/disk/part.c b/disk/part.c
>>> index a6a8f7052b..7af3240ec7 100644
>>> --- a/disk/part.c
>>> +++ b/disk/part.c
>>> @@ -668,6 +668,13 @@ int part_get_info_by_name_type(struct blk_desc
>>> *dev_desc, const char *name,
>>>          part_drv = part_driver_lookup_type(dev_desc);
>>>          if (!part_drv)
>>>                  return -1;
>>> +
>>> +       if (!part_drv->get_info) {
>>> +               PRINTF("## Driver %s does not have the get_info()
>>> method\n",
>>> +                      part_drv->name);
>>
>> Please, use log_debug() to avoid noise on the console on every boot.
>>
>
> I think it's OK to use PRINTF, because of this BUG occurs only when
> user give a bad part configuration, and this error message can prompt
> the user that a configuration error has occurred.
> Besides, 'part_get_info' use PRINTF for this null pointer protection
> too.

Above you write that part_drv->get_info = NULL is part of your
configuration. So it will always be printed. The size of the SPL is very
critical on many boards. We should avoid anything that increases it.

Why is part_get_info_by_name_type() being called in your configuration
which does not provide a partition driver in SPL? Are there some
dependencies missing in the Kconfig files?

Best regards

Heinrich

>
>> Best regards
>>
>> Heinrich
>>
>>> +               return -ENOSYS;
>>> +       }
>>> +
>>>          for (i = 1; i < part_drv->max_entries; i++) {
>>>                  ret = part_drv->get_info(dev_desc, i, info);
>>>                  if (ret != 0) {
>>>
>