Re: [dpdk-dev] [PATCH 2/2] net/mlx5: fix initialization of struct members

[Yongseok Koh <yskoh@mellanox.com>]

> On Nov 14, 2018, at 4:06 AM, Shahaf Shuler <shahafs@mellanox.com> wrote:
> 
> Adding Koh, see below 
> 
> Tuesday, November 13, 2018 9:11 PM, Ali Alnubani:
>> Subject: [PATCH 2/2] net/mlx5: fix initialization of struct members
>> 
>> This patch fixes compilation errors with meson and the clang compiler caused
>> by some of the struct members not being initialized.
>> 
>> ```
>> ../drivers/net/mlx5/mlx5_mr.c:345:37: error: missing field 'end'
>> initializer [-Werror,-Wmissing-field-initializers]
>>                struct mlx5_mr_cache entry = { 0, };
>>                                                  ^
>> ../drivers/net/mlx5/mlx5_mr.c:389:36: error: missing field 'end'
>> initializer [-Werror,-Wmissing-field-initializers]
>>                        struct mlx5_mr_cache ret = { 0, };
>>                                                        ^
>> ../drivers/net/mlx5/mlx5_mr.c:691:35: error: missing field 'end'
>> initializer [-Werror,-Wmissing-field-initializers]
>>                struct mlx5_mr_cache ret = { 0, };
>>                                                ^ ```
>> 
>> The compilation errors reproduce with
>> clang version 3.4.2 (tags/RELEASE_34/dot2-final) on RHEL.
>> 
>> Fixes: e1114ff6a5ab ("net/mlx5: support e-switch flow count action")
>> Fixes: db48f9db5d9f ("net/mlx5: support new flow counter API")
>> Fixes: 974f1e7ef146 ("net/mlx5: add new memory region support")
>> Fixes: 65c9d24170c9 ("net/mlx5: enable loopback by configured mode")
>> Fixes: 87011737b715 ("mlx5: add software counters")
>> Cc: stable@dpdk.org
>> 
>> Signed-off-by: Ali Alnubani <alialnu@mellanox.com>
> 
> [...]
> 
>> diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c index
>> f4b15d3f6..435eaeee2 100644
>> --- a/drivers/net/mlx5/mlx5_mr.c
>> +++ b/drivers/net/mlx5/mlx5_mr.c
>> @@ -342,8 +342,9 @@ mr_insert_dev_cache(struct rte_eth_dev *dev,
>> struct mlx5_mr *mr)
>> 	DRV_LOG(DEBUG, "port %u inserting MR(%p) to global cache",
>> 		dev->data->port_id, (void *)mr);
>> 	for (n = 0; n < mr->ms_bmp_n; ) {
>> -		struct mlx5_mr_cache entry = { 0, };
>> +		struct mlx5_mr_cache entry;
>> 
>> +		memset(&entry, 0, sizeof(entry));
>> 		/* Find a contiguous chunk and advance the index. */
>> 		n = mr_find_next_chunk(mr, &entry, n);
>> 		if (!entry.end)
>> @@ -386,8 +387,9 @@ mr_lookup_dev_list(struct rte_eth_dev *dev, struct
>> mlx5_mr_cache *entry,
>> 		if (mr->ms_n == 0)
>> 			continue;
>> 		for (n = 0; n < mr->ms_bmp_n; ) {
>> -			struct mlx5_mr_cache ret = { 0, };
>> +			struct mlx5_mr_cache ret;
>> 
>> +			memset(&ret, 0, sizeof(ret));
> 
> do you have concerns about the performance w/ this extra memset?

For the three funcs modified with memset here are all slow-paths for the MR.
It is safe for performance.

Thanks,
Yongseok

> 
>> 			n = mr_find_next_chunk(mr, &ret, n);
>> 			if (addr >= ret.start && addr < ret.end) {
>> 				/* Found. */
>> @@ -688,8 +690,9 @@ mlx5_mr_create(struct rte_eth_dev *dev, struct
>> mlx5_mr_cache *entry,
>> 	 */
>> 	for (n = 0; n < ms_n; ++n) {
>> 		uintptr_t start;
>> -		struct mlx5_mr_cache ret = { 0, };
>> +		struct mlx5_mr_cache ret;
>> 
>> +		memset(&ret, 0, sizeof(ret));
>> 		start = data_re.start + n * msl->page_sz;
>> 		/* Exclude memsegs already registered by other MRs. */
>> 		if (mr_lookup_dev(dev, &ret, start) == UINT32_MAX) { diff --
>> git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c index
>> eef485021..b27fc4798 100644
>> --- a/drivers/net/mlx5/mlx5_rxq.c
>> +++ b/drivers/net/mlx5/mlx5_rxq.c
>> @@ -1782,7 +1782,7 @@ mlx5_hrxq_new(struct rte_eth_dev *dev,
>> 	struct mlx5_ind_table_ibv *ind_tbl;
>> 	struct ibv_qp *qp;
>> #ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
>> -	struct mlx5dv_qp_init_attr qp_init_attr = {0};
>> +	struct mlx5dv_qp_init_attr qp_init_attr;
>> #endif
>> 	int err;
>> 
>> @@ -1795,6 +1795,7 @@ mlx5_hrxq_new(struct rte_eth_dev *dev,
>> 		return NULL;
>> 	}
>> #ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
>> +	memset(&qp_init_attr, 0, sizeof(qp_init_attr));
>> 	if (tunnel) {
>> 		qp_init_attr.comp_mask =
>> 
>> 	MLX5DV_QP_INIT_ATTR_MASK_QP_CREATE_FLAGS;
>> diff --git a/drivers/net/mlx5/mlx5_stats.c b/drivers/net/mlx5/mlx5_stats.c
>> index a14d1e491..fccb9af0d 100644
>> --- a/drivers/net/mlx5/mlx5_stats.c
>> +++ b/drivers/net/mlx5/mlx5_stats.c
>> @@ -354,10 +354,11 @@ int
>> mlx5_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *stats)  {
>> 	struct priv *priv = dev->data->dev_private;
>> -	struct rte_eth_stats tmp = {0};
>> +	struct rte_eth_stats tmp;
>> 	unsigned int i;
>> 	unsigned int idx;
>> 
>> +	memset(&tmp, 0, sizeof(tmp));
>> 	/* Add software counters. */
>> 	for (i = 0; (i != priv->rxqs_n); ++i) {
>> 		struct mlx5_rxq_data *rxq = (*priv->rxqs)[i];
>> --
>> 2.11.0
>