Re: [dpdk-dev] [PATCH] ethdev: verify reserved HW ring

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 6/23/2020 5:58 PM, Andrew Rybchenko wrote:
> On 6/23/20 7:41 PM, Ferruh Yigit wrote:
>> Function 'rte_eth_dma_zone_reserve()' returns an existing memzone based
>> on name match, but other requested attributes are discarded.
>> This may cause driver using a memzone with wrong size or alignment.
>>
>> Verify size, alignment and socket_id for matched memzone, and do not use
>> memzone if any one of the attributes are not justified.
>>
>> Reported-by: Renata Saiakhova <renata.saiakhova@ekinops.com>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 
> Few minor notes below, other than that:
> Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
> 
>> ---
>> Cc: Anatoly Burakov <anatoly.burakov@intel.com>
>> ---
>>  lib/librte_ethdev/rte_ethdev.c | 12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
>> index 8e10a6fc3..0fe84aadc 100644
>> --- a/lib/librte_ethdev/rte_ethdev.c
>> +++ b/lib/librte_ethdev/rte_ethdev.c
>> @@ -4202,8 +4202,18 @@ rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, const char *ring_name,
>>  	}
>>  
>>  	mz = rte_memzone_lookup(z_name);
>> -	if (mz)
>> +	if (mz) {
>> +		if ((socket_id != SOCKET_ID_ANY && socket_id != mz->socket_id) ||
>> +				size > mz->len ||
>> +				(uintptr_t)mz->addr & (align - 1)) {
> 
> IMHO, it would be a bit more readable if the result compared
> with 0. Up to you.

Both OK, I can update.

> 
>> +			RTE_ETHDEV_LOG(ERR,
>> +				"memzone %s does not justify the requested attributes\n",
>> +				mz->name);
>> +			return NULL;
> 
> Initially I thought it is a bad behaviour and memzone should
> be freed and reallocated, but it is even worse (implicit free).

+1

> May be it is better to highlight it in the description.

ok

> 
>> +		}
>> +
>>  		return mz;
>> +	}
>>  
>>  	return rte_memzone_reserve_aligned(z_name, size, socket_id,
>>  			RTE_MEMZONE_IOVA_CONTIG, align);
>>
>