Re: [dpdk-dev] [PATCH v2 2/7] net/mlx5: remove redundant objects in probe code

["Xueming(Steven) Li" <xuemingl@mellanox.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Adrien Mazarguil
> Sent: Thursday, June 14, 2018 4:35 PM
> To: Shahaf Shuler <shahafs@mellanox.com>
> Cc: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v2 2/7] net/mlx5: remove redundant objects in probe code
> 
> This patch gets rid of redundant calls to open the device and query its attributes in order to
> simplify the code.
> 
> Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> --
> v2 changes:
> 
> - Minor indent fix on existing code.
> ---
>  drivers/net/mlx5/mlx5.c | 64 +++++++++++++++++++++-----------------------
>  1 file changed, 30 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c index 3bdcb3970..1a5391e63 100644
> --- a/drivers/net/mlx5/mlx5.c
> +++ b/drivers/net/mlx5/mlx5.c
> @@ -654,10 +654,10 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,  {
>  	struct ibv_device **list = NULL;
>  	struct ibv_device *ibv_dev;
> +	struct ibv_context *ctx = NULL;
> +	struct ibv_device_attr_ex attr;
>  	struct mlx5dv_context dv_attr = { .comp_mask = 0 };
>  	int err = 0;
> -	struct ibv_context *attr_ctx = NULL;
> -	struct ibv_device_attr_ex device_attr;
>  	unsigned int vf = 0;
>  	unsigned int mps;
>  	unsigned int cqe_comp;
> @@ -714,12 +714,12 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  		       PCI_DEVICE_ID_MELLANOX_CONNECTX5VF) ||
>  		      (pci_dev->id.device_id ==
>  		       PCI_DEVICE_ID_MELLANOX_CONNECTX5EXVF));
> -		attr_ctx = mlx5_glue->open_device(list[i]);
> +		ctx = mlx5_glue->open_device(list[i]);
>  		rte_errno = errno;
>  		err = rte_errno;
>  		break;
>  	}
> -	if (attr_ctx == NULL) {
> +	if (ctx == NULL) {
>  		switch (err) {
>  		case 0:
>  			DRV_LOG(ERR,
> @@ -748,7 +748,7 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,  #ifdef
> HAVE_IBV_DEVICE_STRIDING_RQ_SUPPORT
>  	dv_attr.comp_mask |= MLX5DV_CONTEXT_MASK_STRIDING_RQ;  #endif
> -	mlx5_glue->dv_query_device(attr_ctx, &dv_attr);
> +	mlx5_glue->dv_query_device(ctx, &dv_attr);
>  	if (dv_attr.flags & MLX5DV_CONTEXT_FLAGS_MPW_ALLOWED) {
>  		if (dv_attr.flags & MLX5DV_CONTEXT_FLAGS_ENHANCED_MPW) {
>  			DRV_LOG(DEBUG, "enhanced MPW is supported"); @@ -822,23 +822,20 @@
> mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  	DRV_LOG(WARNING, "MPLS over GRE/UDP tunnel offloading disabled due to"
>  		" old OFED/rdma-core version or firmware configuration");  #endif
> -	err = mlx5_glue->query_device_ex(attr_ctx, NULL, &device_attr);
> +	err = mlx5_glue->query_device_ex(ctx, NULL, &attr);
>  	if (err) {
>  		DEBUG("ibv_query_device_ex() failed");
>  		goto error;
>  	}
> -	DRV_LOG(INFO, "%u port(s) detected",
> -		device_attr.orig_attr.phys_port_cnt);
> -	for (i = 0; i < device_attr.orig_attr.phys_port_cnt; i++) {
> +	DRV_LOG(INFO, "%u port(s) detected", attr.orig_attr.phys_port_cnt);
> +	for (i = 0; i < attr.orig_attr.phys_port_cnt; i++) {
>  		char name[RTE_ETH_NAME_MAX_LEN];
>  		int len;
>  		uint32_t port = i + 1; /* ports are indexed from one */
> -		struct ibv_context *ctx = NULL;
>  		struct ibv_port_attr port_attr;
>  		struct ibv_pd *pd = NULL;
>  		struct priv *priv = NULL;
>  		struct rte_eth_dev *eth_dev = NULL;
> -		struct ibv_device_attr_ex device_attr_ex;
>  		struct ether_addr mac;
>  		struct mlx5_dev_config config = {
>  			.cqe_comp = cqe_comp,
> @@ -865,7 +862,7 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  		len = snprintf(name, sizeof(name), PCI_PRI_FMT,
>  			 pci_dev->addr.domain, pci_dev->addr.bus,
>  			 pci_dev->addr.devid, pci_dev->addr.function);
> -		if (device_attr.orig_attr.phys_port_cnt > 1)
> +		if (attr.orig_attr.phys_port_cnt > 1)
>  			snprintf(name + len, sizeof(name), " port %u", i);
>  		if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
>  			eth_dev = rte_eth_dev_attach_secondary(name);
> @@ -907,7 +904,8 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  			continue;
>  		}
>  		DRV_LOG(DEBUG, "using port %u", port);
> -		ctx = mlx5_glue->open_device(ibv_dev);
> +		if (!ctx)
> +			ctx = mlx5_glue->open_device(ibv_dev);
>  		if (ctx == NULL) {
>  			err = ENODEV;
>  			goto port_error;
> @@ -949,7 +947,7 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  		priv->ctx = ctx;
>  		strncpy(priv->ibdev_path, priv->ctx->device->ibdev_path,
>  			sizeof(priv->ibdev_path));
> -		priv->device_attr = device_attr;
> +		priv->device_attr = attr;
>  		priv->port = port;
>  		priv->pd = pd;
>  		priv->mtu = ETHER_MTU;
> @@ -960,17 +958,12 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  				strerror(rte_errno));
>  			goto port_error;
>  		}
> -		err = mlx5_glue->query_device_ex(ctx, NULL, &device_attr_ex);
> -		if (err) {
> -			DRV_LOG(ERR, "ibv_query_device_ex() failed");
> -			goto port_error;
> -		}
> -		config.hw_csum = !!(device_attr_ex.device_cap_flags_ex &
> +		config.hw_csum = !!(attr.device_cap_flags_ex &
>  				    IBV_DEVICE_RAW_IP_CSUM);
>  		DRV_LOG(DEBUG, "checksum offloading is %ssupported",
>  			(config.hw_csum ? "" : "not "));
>  #ifdef HAVE_IBV_DEVICE_COUNTERS_SET_SUPPORT
> -		config.flow_counter_en = !!(device_attr.max_counter_sets);
> +		config.flow_counter_en = !!attr.max_counter_sets;
>  		mlx5_glue->describe_counter_set(ctx, 0, &cs_desc);
>  		DRV_LOG(DEBUG,
>  			"counter type = %d, num of cs = %ld, attributes = %d", @@ -978,7 +971,7 @@
> mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  			cs_desc.attributes);
>  #endif
>  		config.ind_table_max_size =
> -			device_attr_ex.rss_caps.max_rwq_indirection_table_size;
> +			attr.rss_caps.max_rwq_indirection_table_size;
>  		/* Remove this check once DPDK supports larger/variable
>  		 * indirection tables. */
>  		if (config.ind_table_max_size >
> @@ -986,29 +979,28 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  			config.ind_table_max_size = ETH_RSS_RETA_SIZE_512;
>  		DRV_LOG(DEBUG, "maximum Rx indirection table size is %u",
>  			config.ind_table_max_size);
> -		config.hw_vlan_strip = !!(device_attr_ex.raw_packet_caps &
> +		config.hw_vlan_strip = !!(attr.raw_packet_caps &
>  					 IBV_RAW_PACKET_CAP_CVLAN_STRIPPING);
>  		DRV_LOG(DEBUG, "VLAN stripping is %ssupported",
>  			(config.hw_vlan_strip ? "" : "not "));
> 
> -		config.hw_fcs_strip = !!(device_attr_ex.raw_packet_caps &
> +		config.hw_fcs_strip = !!(attr.raw_packet_caps &
>  					 IBV_RAW_PACKET_CAP_SCATTER_FCS);
>  		DRV_LOG(DEBUG, "FCS stripping configuration is %ssupported",
>  			(config.hw_fcs_strip ? "" : "not "));
> 
>  #ifdef HAVE_IBV_WQ_FLAG_RX_END_PADDING
> -		config.hw_padding = !!device_attr_ex.rx_pad_end_addr_align;
> +		config.hw_padding = !!attr.rx_pad_end_addr_align;
>  #endif
>  		DRV_LOG(DEBUG,
>  			"hardware Rx end alignment padding is %ssupported",
>  			(config.hw_padding ? "" : "not "));
>  		config.vf = vf;
> -		config.tso = ((device_attr_ex.tso_caps.max_tso > 0) &&
> -			      (device_attr_ex.tso_caps.supported_qpts &
> -			      (1 << IBV_QPT_RAW_PACKET)));
> +		config.tso = (attr.tso_caps.max_tso > 0 &&
> +			      (attr.tso_caps.supported_qpts &
> +			       (1 << IBV_QPT_RAW_PACKET)));
>  		if (config.tso)
> -			config.tso_max_payload_sz =
> -					device_attr_ex.tso_caps.max_tso;
> +			config.tso_max_payload_sz = attr.tso_caps.max_tso;
>  		if (config.mps && !mps) {
>  			DRV_LOG(ERR,
>  				"multi-packet send not supported on this device"
> @@ -1168,14 +1160,18 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  				 priv, mem_event_cb);
>  		rte_rwlock_write_unlock(&mlx5_shared_data->mem_event_rwlock);
>  		rte_eth_dev_probing_finish(eth_dev);
> +		/*
> +		 * Each eth_dev instance is assigned its own Verbs context,
> +		 * since this one is consumed, let the next iteration open
> +		 * another.
> +		 */
> +		ctx = NULL;
>  		continue;
>  port_error:
>  		if (priv)
>  			rte_free(priv);
>  		if (pd)
>  			claim_zero(mlx5_glue->dealloc_pd(pd));
> -		if (ctx)
> -			claim_zero(mlx5_glue->close_device(ctx));
>  		if (eth_dev && rte_eal_process_type() == RTE_PROC_PRIMARY)
>  			rte_eth_dev_release_port(eth_dev);
>  		break;
> @@ -1187,8 +1183,8 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
>  	 * way to enumerate the registered ethdevs to free the previous ones.
>  	 */
>  error:
> -	if (attr_ctx)
> -		claim_zero(mlx5_glue->close_device(attr_ctx));
> +	if (ctx)
> +		claim_zero(mlx5_glue->close_device(ctx));
>  	if (list)
>  		mlx5_glue->free_device_list(list);
>  	if (err) {
> --
> 2.11.0

Reviewed-by: Xueming Li <xuemingl@mellanox.com>