[PATCH v2] nvme: Fix handling of large MDTS values

[Bart Van Assche]

On 4/1/21 8:54 AM, Keith Busch wrote:
> On Wed, Mar 31, 2021 at 08:59:52PM -0700, Bart Van Assche wrote:
>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>> index 40215a0246e4..25bc28e8845f 100644
>> --- a/drivers/nvme/host/core.c
>> +++ b/drivers/nvme/host/core.c
>> @@ -3123,10 +3123,11 @@ static int nvme_init_identify(struct nvme_ctrl *ctrl)
>>  
>>  	atomic_set(&ctrl->abort_limit, id->acl + 1);
>>  	ctrl->vwc = id->vwc;
>> -	if (id->mdts)
>> -		max_hw_sectors = 1 << (id->mdts + page_shift - 9);
>> -	else
>> +	max_hw_sectors = UINT_MAX;
>> +	if (id->mdts && check_shl_overflow(1U, id->mdts + page_shift - 9,
>> +					   &max_hw_sectors)) {
>>  		max_hw_sectors = UINT_MAX;
>> +	}
> 
> The condition can be rearranged so that max_hw_sectors is set to
> UINT_MAX just once:
> 
> 	if (!id->mdts || check_shl_overflow(1U, id->mdts + page_shift - 9,
> 					    &max_hw_sectors)) {
>   		max_hw_sectors = UINT_MAX;
> 	}

Hi Keith,

That's an interesting suggestion. I will integrate this change in my
patch and repost it.

Thanks,

Bart.