Re: [PATCH] powerpc/fadump: reset dump area size variable if memblock reserve fails

[Sourabh Jain <sourabhjain@linux.ibm.com>]

On 03/07/23 16:59, Michael Ellerman wrote:
> Sourabh Jain <sourabhjain@linux.ibm.com> writes:
>> Hello Michael,
>>
>> Do you have any feedback or comments regarding this patch?
>>
>> Thanks,
>> Sourabh
>>
>> On 08/06/23 14:52, Sourabh Jain wrote:
>>> If the memory reservation process (memblock_reserve) fails to reserve
>>> the memory, the reserve dump variable retains the dump area size.
>>> Consequently, the size of the dump area calculated for reservation
>>> is displayed in /sys/kernel/fadump/mem_reserved.
>>>
>>> To resolve this issue, the reserve dump area size variable is set to 0
>>> if the memblock_reserve fails to reserve memory.
>>>
>>> Fixes: 8255da95e545 ("powerpc/fadump: release all the memory above boot memory size")
>>> Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
>>> Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
>>> ---
>>>    arch/powerpc/kernel/fadump.c | 1 +
>>>    1 file changed, 1 insertion(+)
>>>
>>> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
>>> index ea0a073abd96..a8f2c3b2fa1e 100644
>>> --- a/arch/powerpc/kernel/fadump.c
>>> +++ b/arch/powerpc/kernel/fadump.c
>>> @@ -641,6 +641,7 @@ int __init fadump_reserve_mem(void)
>>>    			goto error_out;
>>>    
>>>    		if (memblock_reserve(base, size)) {
>>> +			fw_dump.reserve_dump_area_size = 0;
>>>    			pr_err("Failed to reserve memory!\n");
>>>    			goto error_out;
>>>    		}
> Shouldn't reserve_dump_area_size be set to zero at error_out, which
> already clears fadump_enabled?
>
> 	return ret;
> error_out:
> 	fw_dump.fadump_enabled = 0;
> 	return 0;
> }
>
>
> Otherwise the code immediately above will suffer from the same issue
> won't it?
>
> 		if (fw_dump.ops->fadump_setup_metadata &&
> 		    (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
> 			goto error_out;

Agree, resetting fw_dump.reserve_dump_area_size below error_out label is 
better.

Thanks for the review. I will send v2.

Sourabh Jain