[v2] net/mlx5: set RSS key to NULL to indicate default RSS

Message ID 1541062744-25491-1-git-send-email-ophirmu@mellanox.com (mailing list archive)
State Superseded, archived
Delegated to: Shahaf Shuler
Headers
Series [v2] net/mlx5: set RSS key to NULL to indicate default RSS |

Checks

Context Check Description
ci/Intel-compilation success Compilation OK

Commit Message

Ophir Munk Nov. 1, 2018, 8:59 a.m. UTC
  Applications which add RSS rules must supply an RSS key and length.
If an application is only interested in default RSS operation it
should not care about the exact RSS key.
By setting the key to NULL - the PMD will use the default RSS key.
In addition if the application does not care about the RSS type it can
set it to 0 and the PMD will use the default type (ETH_RSS_IP).

Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
---
 doc/guides/nics/mlx5.rst           |  1 +
 drivers/net/mlx5/mlx5_flow.c       |  8 +++++++-
 drivers/net/mlx5/mlx5_flow_dv.c    |  8 ++++++--
 drivers/net/mlx5/mlx5_flow_verbs.c |  9 +++++++--
 drivers/net/mlx5/mlx5_rxq.c        | 14 ++++++--------
 lib/librte_ethdev/rte_flow.h       |  2 +-
 6 files changed, 28 insertions(+), 14 deletions(-)
  

Comments

Shahaf Shuler Nov. 1, 2018, 2 p.m. UTC | #1
Hi Ophir, 

Thursday, November 1, 2018 10:59 AM, Ophir Munk:
> Subject: [PATCH v2] net/mlx5: set RSS key to NULL to indicate default RSS
> 
> Applications which add RSS rules must supply an RSS key and length.
> If an application is only interested in default RSS operation it should not care
> about the exact RSS key.
> By setting the key to NULL - the PMD will use the default RSS key.
> In addition if the application does not care about the RSS type it can set it to 0
> and the PMD will use the default type (ETH_RSS_IP).
> 
> Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
> ---
>  doc/guides/nics/mlx5.rst           |  1 +
>  drivers/net/mlx5/mlx5_flow.c       |  8 +++++++-
>  drivers/net/mlx5/mlx5_flow_dv.c    |  8 ++++++--
>  drivers/net/mlx5/mlx5_flow_verbs.c |  9 +++++++--
>  drivers/net/mlx5/mlx5_rxq.c        | 14 ++++++--------
>  lib/librte_ethdev/rte_flow.h       |  2 +-
>  6 files changed, 28 insertions(+), 14 deletions(-)
> 
> diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index
> 6769628..de8f15b 100644
> --- a/doc/guides/nics/mlx5.rst
> +++ b/doc/guides/nics/mlx5.rst
> @@ -54,6 +54,7 @@ Features
>  - Support for scattered TX and RX frames.
>  - IPv4, IPv6, TCPv4, TCPv6, UDPv4 and UDPv6 RSS on any number of queues.
>  - Several RSS hash keys, one for each flow type.
> +- NULL RSS key indicates default RSS key

I don't think it is a feature, it should be an API implementation. 

>  - Configurable RETA table.
>  - Support for multiple MAC addresses.
>  - VLAN filtering.
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index 280af0a..5742989 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -912,7 +912,13 @@ uint32_t mlx5_flow_adjust_priority(struct
> rte_eth_dev *dev, int32_t priority,
> 
> RTE_FLOW_ERROR_TYPE_ACTION_CONF,
>  					  &rss->level,
>  					  "tunnel RSS is not supported");
> -	if (rss->key_len < MLX5_RSS_HASH_KEY_LEN)
> +	/* allow RSS key_len 0 in case of NULL (default) RSS key */

Missing period. 

> +	if (rss->key_len == 0 && rss->key != NULL)
> +		return rte_flow_error_set(error, ENOTSUP,
> +
> RTE_FLOW_ERROR_TYPE_ACTION_CONF,
> +					  &rss->key_len,
> +					  "RSS hash key length 0");
> +	if (rss->key_len > 0 && rss->key_len < MLX5_RSS_HASH_KEY_LEN)

Can't you simplify using a single condition: 
If (rss->key && rss->key_len < MLX5_RSS_HASH_KEY_LEN)

Same rss->key addition should be for the case the key_len is too large. 

>  		return rte_flow_error_set(error, ENOTSUP,
> 
> RTE_FLOW_ERROR_TYPE_ACTION_CONF,
>  					  &rss->key_len,
> diff --git a/drivers/net/mlx5/mlx5_flow_dv.c
> b/drivers/net/mlx5/mlx5_flow_dv.c index 8f729f4..fd52bf4 100644
> --- a/drivers/net/mlx5/mlx5_flow_dv.c
> +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> @@ -1056,6 +1056,7 @@
>  {
>  	const struct rte_flow_action_queue *queue;
>  	const struct rte_flow_action_rss *rss;
> +	uint8_t	*rss_key;

Why no declare it inside the RSS case? 

>  	int actions_n = dev_flow->dv.actions_n;
>  	struct rte_flow *flow = dev_flow->flow;
> 
> @@ -1094,8 +1095,11 @@
>  			memcpy((*flow->queue), rss->queue,
>  			       rss->queue_num * sizeof(uint16_t));
>  		flow->rss.queue_num = rss->queue_num;
> -		memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
> -		flow->rss.types = rss->types;
> +		/* NULL RSS key indicates default RSS key */

Missing period. 

> +		rss_key = (!rss->key) ? rss_hash_default_key : rss->key;
> +		memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);

For consistency you should also set the key_len on the flow structure to MLX5_RSS_HASH_KEY_LEN.

> +		/* RSS type 0 indicates default RSS type ETH_RSS_IP */

Period. 

> +		flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
>  		flow->rss.level = rss->level;
>  		/* Added to array only in apply since we need the QP */
>  		flow->actions |= MLX5_FLOW_ACTION_RSS; diff --git
> a/drivers/net/mlx5/mlx5_flow_verbs.c
> b/drivers/net/mlx5/mlx5_flow_verbs.c
> index 81bc39f..ae9042f 100644
> --- a/drivers/net/mlx5/mlx5_flow_verbs.c
> +++ b/drivers/net/mlx5/mlx5_flow_verbs.c
> @@ -925,14 +925,19 @@
>  				struct mlx5_flow *dev_flow)
>  {
>  	const struct rte_flow_action_rss *rss = action->conf;
> +	const uint8_t *rss_key;
>  	struct rte_flow *flow = dev_flow->flow;
> 
>  	if (flow->queue)
>  		memcpy((*flow->queue), rss->queue,
>  		       rss->queue_num * sizeof(uint16_t));
>  	flow->rss.queue_num = rss->queue_num;
> -	memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
> -	flow->rss.types = rss->types;
> +
> +	/* NULL RSS key indicates default RSS key */

period

> +	rss_key = !rss->key ? rss_hash_default_key : rss->key;

For consistency you should also set the key_len on the flow structure to MLX5_RSS_HASH_KEY_LEN. 

> +	memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);
> +	/* RSS type 0 indicates default RSS type (ETH_RSS_IP) */

period

> +	flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
>  	flow->rss.level = rss->level;
>  	*action_flags |= MLX5_FLOW_ACTION_RSS;  } diff --git
> a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c index
> ed993ea..36fc202 100644
> --- a/drivers/net/mlx5/mlx5_rxq.c
> +++ b/drivers/net/mlx5/mlx5_rxq.c
> @@ -1783,10 +1783,6 @@ struct mlx5_hrxq *
>  		rte_errno = ENOMEM;
>  		return NULL;
>  	}
> -	if (!rss_key_len) {
> -		rss_key_len = MLX5_RSS_HASH_KEY_LEN;
> -		rss_key = rss_hash_default_key;
> -	}
>  #ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
>  	qp = mlx5_glue->dv_create_qp
>  		(priv->ctx,
> @@ -1798,8 +1794,7 @@ struct mlx5_hrxq *
>  				IBV_QP_INIT_ATTR_RX_HASH,
>  			.rx_hash_conf = (struct ibv_rx_hash_conf){
>  				.rx_hash_function =
> IBV_RX_HASH_FUNC_TOEPLITZ,
> -				.rx_hash_key_len = rss_key_len ?
> rss_key_len :
> -						   MLX5_RSS_HASH_KEY_LEN,
> +				.rx_hash_key_len = rss_key_len,
>  				.rx_hash_key = rss_key ?
>  					       (void *)(uintptr_t)rss_key :
>  					       rss_hash_default_key,
> @@ -1824,8 +1819,7 @@ struct mlx5_hrxq *
>  				IBV_QP_INIT_ATTR_RX_HASH,
>  			.rx_hash_conf = (struct ibv_rx_hash_conf){
>  				.rx_hash_function =
> IBV_RX_HASH_FUNC_TOEPLITZ,
> -				.rx_hash_key_len = rss_key_len ?
> rss_key_len :
> -						   MLX5_RSS_HASH_KEY_LEN,
> +				.rx_hash_key_len = rss_key_len,
>  				.rx_hash_key = rss_key ?
>  					       (void *)(uintptr_t)rss_key :
>  					       rss_hash_default_key,
> @@ -1888,8 +1882,12 @@ struct mlx5_hrxq *
>  	LIST_FOREACH(hrxq, &priv->hrxqs, next) {
>  		struct mlx5_ind_table_ibv *ind_tbl;
> 
> +		if (!rss_key_len)
> +			rss_key_len = MLX5_RSS_HASH_KEY_LEN;

In the mlx5_hrxq_new above you trust the rss_key_len to be the correct one, and it is ok since you validate it on the rss validate function.
Why it is not the case here as well? 

>  		if (hrxq->rss_key_len != rss_key_len)
>  			continue;
> +		if (!rss_key)
> +			rss_key = rss_hash_default_key;

Same question. You already copied to correct key in flow_verbs_translate_action_rss or on the flow_dv_create_action funciton. 

>  		if (memcmp(hrxq->rss_key, rss_key, rss_key_len))
>  			continue;
>  		if (hrxq->hash_fields != hash_fields) diff --git
> a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h index
> c0fe879..6cc72ab 100644
> --- a/lib/librte_ethdev/rte_flow.h
> +++ b/lib/librte_ethdev/rte_flow.h
> @@ -1785,7 +1785,7 @@ struct rte_flow_action_rss {
>  	uint64_t types; /**< Specific RSS hash types (see ETH_RSS_*). */
>  	uint32_t key_len; /**< Hash key length in bytes. */
>  	uint32_t queue_num; /**< Number of entries in @p queue. */
> -	const uint8_t *key; /**< Hash key. */
> +	const uint8_t *key; /**< Hash key. NULL should indicate default key

This change should be on a separate commit in a separate series. 
It is better to put the doc update above the function and not inline on the field so that you can elaborate more. 
Also you are missing the same doc update for the types field. 

Note: your patch for mlx5 can be accepted also w/o it, but it is better to align all vendors and I think it is aligned w/ the spirit of the rte_flow maintainer. 

> */
>  	const uint16_t *queue; /**< Queue indices to use. */  };
> 
> --
> 1.8.3.1
  
Ophir Munk Nov. 2, 2018, 5:54 p.m. UTC | #2
> -----Original Message-----
> From: Shahaf Shuler
> Sent: Thursday, November 01, 2018 4:01 PM
> To: Ophir Munk <ophirmu@mellanox.com>; dev@dpdk.org; Yongseok Koh 
> <yskoh@mellanox.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>; Olga Shern 
> <olgas@mellanox.com>; Asaf Penso <asafp@mellanox.com>
> Subject: RE: [PATCH v2] net/mlx5: set RSS key to NULL to indicate 
> default RSS
> 
> Hi Ophir,
> 
> Thursday, November 1, 2018 10:59 AM, Ophir Munk:
> > Subject: [PATCH v2] net/mlx5: set RSS key to NULL to indicate 
> > default RSS
> >
> > Applications which add RSS rules must supply an RSS key and length.
> > If an application is only interested in default RSS operation it 
> > should not care about the exact RSS key.
> > By setting the key to NULL - the PMD will use the default RSS key.
> > In addition if the application does not care about the RSS type it 
> > can set it to 0 and the PMD will use the default type (ETH_RSS_IP).
> >
> > Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
> > ---
> >  doc/guides/nics/mlx5.rst           |  1 +
> >  drivers/net/mlx5/mlx5_flow.c       |  8 +++++++-
> >  drivers/net/mlx5/mlx5_flow_dv.c    |  8 ++++++--
> >  drivers/net/mlx5/mlx5_flow_verbs.c |  9 +++++++--
> >  drivers/net/mlx5/mlx5_rxq.c        | 14 ++++++--------
> >  lib/librte_ethdev/rte_flow.h       |  2 +-
> >  6 files changed, 28 insertions(+), 14 deletions(-)
> >
> > diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst 
> > index 6769628..de8f15b 100644
> > --- a/doc/guides/nics/mlx5.rst
> > +++ b/doc/guides/nics/mlx5.rst
> > @@ -54,6 +54,7 @@ Features
> >  - Support for scattered TX and RX frames.
> >  - IPv4, IPv6, TCPv4, TCPv6, UDPv4 and UDPv6 RSS on any number of
> queues.
> >  - Several RSS hash keys, one for each flow type.
> > +- NULL RSS key indicates default RSS key
> 
> I don't think it is a feature, it should be an API implementation.

1. There is no "API implementation" section in the mlx5.rst doc. Please indicate where exactly you think it should be added.
2. I think you can consider this a feature: applications can use default RSS without knowing any specific RSS parameters.
Setting key to NULL is just the mean to get it (maybe should not be mentioned).

How about:
Default RSS operation with no hash key specification

> 
> >  - Configurable RETA table.
> >  - Support for multiple MAC addresses.
> >  - VLAN filtering.
> > diff --git a/drivers/net/mlx5/mlx5_flow.c 
> > b/drivers/net/mlx5/mlx5_flow.c index 280af0a..5742989 100644
> > --- a/drivers/net/mlx5/mlx5_flow.c
> > +++ b/drivers/net/mlx5/mlx5_flow.c
> > @@ -912,7 +912,13 @@ uint32_t mlx5_flow_adjust_priority(struct 
> > rte_eth_dev *dev, int32_t priority,
> >
> > RTE_FLOW_ERROR_TYPE_ACTION_CONF,
> >  					  &rss->level,
> >  					  "tunnel RSS is not supported");
> > -	if (rss->key_len < MLX5_RSS_HASH_KEY_LEN)
> > +	/* allow RSS key_len 0 in case of NULL (default) RSS key */
> 
> Missing period.

Will be added in v3

> 
> > +	if (rss->key_len == 0 && rss->key != NULL)
> > +		return rte_flow_error_set(error, ENOTSUP,
> > +
> > RTE_FLOW_ERROR_TYPE_ACTION_CONF,
> > +					  &rss->key_len,
> > +					  "RSS hash key length 0");
> > +	if (rss->key_len > 0 && rss->key_len < MLX5_RSS_HASH_KEY_LEN)
> 
> Can't you simplify using a single condition:
> If (rss->key && rss->key_len < MLX5_RSS_HASH_KEY_LEN)
> 

Do you mean that if key==NULL we do not care about the key_len?
(since if key==NULL key_len can have any value? 
Wil update in V3

> Same rss->key addition should be for the case the key_len is too large.
> 
> >  		return rte_flow_error_set(error, ENOTSUP,
> >
> > RTE_FLOW_ERROR_TYPE_ACTION_CONF,
> >  					  &rss->key_len,
> > diff --git a/drivers/net/mlx5/mlx5_flow_dv.c 
> > b/drivers/net/mlx5/mlx5_flow_dv.c index 8f729f4..fd52bf4 100644
> > --- a/drivers/net/mlx5/mlx5_flow_dv.c
> > +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> > @@ -1056,6 +1056,7 @@
> >  {
> >  	const struct rte_flow_action_queue *queue;
> >  	const struct rte_flow_action_rss *rss;
> > +	uint8_t	*rss_key;
> 
> Why no declare it inside the RSS case?

It is consistent with the coding style in this file.
1. There is no variable declaration inside any case.
2. If rss_key is declared inside the RSS case - the same should be for rss variable (for consistency) and there can be more cases to check.

> 
> >  	int actions_n = dev_flow->dv.actions_n;
> >  	struct rte_flow *flow = dev_flow->flow;
> >
> > @@ -1094,8 +1095,11 @@
> >  			memcpy((*flow->queue), rss->queue,
> >  			       rss->queue_num * sizeof(uint16_t));
> >  		flow->rss.queue_num = rss->queue_num;
> > -		memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
> > -		flow->rss.types = rss->types;
> > +		/* NULL RSS key indicates default RSS key */
> 
> Missing period.

Will be added in v3

> 
> > +		rss_key = (!rss->key) ? rss_hash_default_key : rss->key;
> > +		memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);
> 
> For consistency you should also set the key_len on the flow structure 
> to MLX5_RSS_HASH_KEY_LEN.
> 

There is no key_len on the flow structure. 
I guess the key_len field is missing since it is redundant (key_len is always 40 bytes).

> > +		/* RSS type 0 indicates default RSS type ETH_RSS_IP */
> 
> Period.

Will be added in v3

> 
> > +		flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
> >  		flow->rss.level = rss->level;
> >  		/* Added to array only in apply since we need the QP */
> >  		flow->actions |= MLX5_FLOW_ACTION_RSS; diff --git 
> > a/drivers/net/mlx5/mlx5_flow_verbs.c
> > b/drivers/net/mlx5/mlx5_flow_verbs.c
> > index 81bc39f..ae9042f 100644
> > --- a/drivers/net/mlx5/mlx5_flow_verbs.c
> > +++ b/drivers/net/mlx5/mlx5_flow_verbs.c
> > @@ -925,14 +925,19 @@
> >  				struct mlx5_flow *dev_flow)
> >  {
> >  	const struct rte_flow_action_rss *rss = action->conf;
> > +	const uint8_t *rss_key;
> >  	struct rte_flow *flow = dev_flow->flow;
> >
> >  	if (flow->queue)
> >  		memcpy((*flow->queue), rss->queue,
> >  		       rss->queue_num * sizeof(uint16_t));
> >  	flow->rss.queue_num = rss->queue_num;
> > -	memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
> > -	flow->rss.types = rss->types;
> > +
> > +	/* NULL RSS key indicates default RSS key */
> 
> period

Will be added in v3

> 
> > +	rss_key = !rss->key ? rss_hash_default_key : rss->key;
> 
> For consistency you should also set the key_len on the flow structure 
> to MLX5_RSS_HASH_KEY_LEN.
> 

There is no key_len on the flow structure.

> > +	memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);
> > +	/* RSS type 0 indicates default RSS type (ETH_RSS_IP) */
> 
> period

Will be added in v3

> 
> > +	flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
> >  	flow->rss.level = rss->level;
> >  	*action_flags |= MLX5_FLOW_ACTION_RSS;  } diff --git 
> > a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c index
> > ed993ea..36fc202 100644
> > --- a/drivers/net/mlx5/mlx5_rxq.c
> > +++ b/drivers/net/mlx5/mlx5_rxq.c
> > @@ -1783,10 +1783,6 @@ struct mlx5_hrxq *
> >  		rte_errno = ENOMEM;
> >  		return NULL;
> >  	}
> > -	if (!rss_key_len) {
> > -		rss_key_len = MLX5_RSS_HASH_KEY_LEN;
> > -		rss_key = rss_hash_default_key;
> > -	}
> >  #ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
> >  	qp = mlx5_glue->dv_create_qp
> >  		(priv->ctx,
> > @@ -1798,8 +1794,7 @@ struct mlx5_hrxq *
> >  				IBV_QP_INIT_ATTR_RX_HASH,
> >  			.rx_hash_conf = (struct ibv_rx_hash_conf){
> >  				.rx_hash_function =
> > IBV_RX_HASH_FUNC_TOEPLITZ,
> > -				.rx_hash_key_len = rss_key_len ?
> > rss_key_len :
> > -
> MLX5_RSS_HASH_KEY_LEN,
> > +				.rx_hash_key_len = rss_key_len,
> >  				.rx_hash_key = rss_key ?
> >  					       (void *)(uintptr_t)rss_key :
> >  					       rss_hash_default_key,
> > @@ -1824,8 +1819,7 @@ struct mlx5_hrxq *
> >  				IBV_QP_INIT_ATTR_RX_HASH,
> >  			.rx_hash_conf = (struct ibv_rx_hash_conf){
> >  				.rx_hash_function =
> > IBV_RX_HASH_FUNC_TOEPLITZ,
> > -				.rx_hash_key_len = rss_key_len ?
> > rss_key_len :
> > -
> MLX5_RSS_HASH_KEY_LEN,
> > +				.rx_hash_key_len = rss_key_len,
> >  				.rx_hash_key = rss_key ?
> >  					       (void *)(uintptr_t)rss_key :
> >  					       rss_hash_default_key,
> > @@ -1888,8 +1882,12 @@ struct mlx5_hrxq *
> >  	LIST_FOREACH(hrxq, &priv->hrxqs, next) {
> >  		struct mlx5_ind_table_ibv *ind_tbl;
> >
> > +		if (!rss_key_len)
> > +			rss_key_len = MLX5_RSS_HASH_KEY_LEN;
> 
> In the mlx5_hrxq_new above you trust the rss_key_len to be the correct 
> one, and it is ok since you validate it on the rss validate function.
> Why it is not the case here as well?
> 

Will be updated in v3.
Remark: rss_key_len assignment can be dropped  because calling mlx5_hrxq_get is done with constant MLX5_RSS_HASH_KEY_LEN already assigned to rss_key_len 

> >  		if (hrxq->rss_key_len != rss_key_len)
> >  			continue;
> > +		if (!rss_key)
> > +			rss_key = rss_hash_default_key;
> 
> Same question. You already copied to correct key in 
> flow_verbs_translate_action_rss or on the flow_dv_create_action funciton.

Will be dropped in v3
Will also drop in v3 another legacy code which does redundant rss_key==NULL check

> 
> >  		if (memcmp(hrxq->rss_key, rss_key, rss_key_len))
> >  			continue;
> >  		if (hrxq->hash_fields != hash_fields) diff --git 
> > a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h index 
> > c0fe879..6cc72ab 100644
> > --- a/lib/librte_ethdev/rte_flow.h
> > +++ b/lib/librte_ethdev/rte_flow.h
> > @@ -1785,7 +1785,7 @@ struct rte_flow_action_rss {
> >  	uint64_t types; /**< Specific RSS hash types (see ETH_RSS_*). */
> >  	uint32_t key_len; /**< Hash key length in bytes. */
> >  	uint32_t queue_num; /**< Number of entries in @p queue. */
> > -	const uint8_t *key; /**< Hash key. */
> > +	const uint8_t *key; /**< Hash key. NULL should indicate default 
> > +key
> 
> This change should be on a separate commit in a separate series.
> It is better to put the doc update above the function and not inline 
> on the field so that you can elaborate more.
> Also you are missing the same doc update for the types field.
> 

Will issue a sepearte commit in a separate series

> Note: your patch for mlx5 can be accepted also w/o it, but it is 
> better to align all vendors and I think it is aligned w/ the spirit of 
> the rte_flow maintainer.
> 
> > */
> >  	const uint16_t *queue; /**< Queue indices to use. */  };
> >
> > --
> > 1.8.3.1
  
Ophir Munk Nov. 3, 2018, 5:18 p.m. UTC | #3
Please see comments inline

> -----Original Message-----
> From: Ophir Munk
> Sent: Friday, November 02, 2018 7:55 PM
> To: dev@dpdk.org; Yongseok Koh <yskoh@mellanox.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>; Asaf Penso
> <asafp@mellanox.com>; Olga Shern <olgas@mellanox.com>; Ophir Munk
> <ophirmu@mellanox.com>
> Subject: FW: [PATCH v2] net/mlx5: set RSS key to NULL to indicate default
> RSS
> 
> 
> > -----Original Message-----
> > From: Shahaf Shuler
> > Sent: Thursday, November 01, 2018 4:01 PM
> > To: Ophir Munk <ophirmu@mellanox.com>; dev@dpdk.org; Yongseok Koh
> > <yskoh@mellanox.com>
> > Cc: Thomas Monjalon <thomas@monjalon.net>; Olga Shern
> > <olgas@mellanox.com>; Asaf Penso <asafp@mellanox.com>
> > Subject: RE: [PATCH v2] net/mlx5: set RSS key to NULL to indicate
> > default RSS
> >
> > Hi Ophir,
> >
> 
> >
> > > +	if (rss->key_len == 0 && rss->key != NULL)
> > > +		return rte_flow_error_set(error, ENOTSUP,
> > > +
> > > RTE_FLOW_ERROR_TYPE_ACTION_CONF,
> > > +					  &rss->key_len,
> > > +					  "RSS hash key length 0");
> > > +	if (rss->key_len > 0 && rss->key_len < MLX5_RSS_HASH_KEY_LEN)
> >
> > Can't you simplify using a single condition:
> > If (rss->key && rss->key_len < MLX5_RSS_HASH_KEY_LEN)
> >
> 
> Do you mean that if key==NULL we do not care about the key_len?
> (since if key==NULL key_len can have any value?
> Wil update in V3

After applying in v3 the reviewed condition code - action validation confirms a NULL key with key length 6.
But then testpmd crashes when creating the rule. Crash occurs in rte_flow_conv_action_conf().
When reverting to v2 condition code action validation is failing (as expected) with error message:
Caught error type 15 (action configuration): cause: 0x7fffffffbf18, RSS hash key too small: Unknown error 95
and flow creation fails with the same error.

I will issue v4 with v2  condition code.

> 
> > Same rss->key addition should be for the case the key_len is too large.
  

Patch

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index 6769628..de8f15b 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -54,6 +54,7 @@  Features
 - Support for scattered TX and RX frames.
 - IPv4, IPv6, TCPv4, TCPv6, UDPv4 and UDPv6 RSS on any number of queues.
 - Several RSS hash keys, one for each flow type.
+- NULL RSS key indicates default RSS key
 - Configurable RETA table.
 - Support for multiple MAC addresses.
 - VLAN filtering.
diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index 280af0a..5742989 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -912,7 +912,13 @@  uint32_t mlx5_flow_adjust_priority(struct rte_eth_dev *dev, int32_t priority,
 					  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
 					  &rss->level,
 					  "tunnel RSS is not supported");
-	if (rss->key_len < MLX5_RSS_HASH_KEY_LEN)
+	/* allow RSS key_len 0 in case of NULL (default) RSS key */
+	if (rss->key_len == 0 && rss->key != NULL)
+		return rte_flow_error_set(error, ENOTSUP,
+					  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
+					  &rss->key_len,
+					  "RSS hash key length 0");
+	if (rss->key_len > 0 && rss->key_len < MLX5_RSS_HASH_KEY_LEN)
 		return rte_flow_error_set(error, ENOTSUP,
 					  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
 					  &rss->key_len,
diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 8f729f4..fd52bf4 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -1056,6 +1056,7 @@ 
 {
 	const struct rte_flow_action_queue *queue;
 	const struct rte_flow_action_rss *rss;
+	uint8_t	*rss_key;
 	int actions_n = dev_flow->dv.actions_n;
 	struct rte_flow *flow = dev_flow->flow;
 
@@ -1094,8 +1095,11 @@ 
 			memcpy((*flow->queue), rss->queue,
 			       rss->queue_num * sizeof(uint16_t));
 		flow->rss.queue_num = rss->queue_num;
-		memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
-		flow->rss.types = rss->types;
+		/* NULL RSS key indicates default RSS key */
+		rss_key = (!rss->key) ? rss_hash_default_key : rss->key;
+		memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);
+		/* RSS type 0 indicates default RSS type ETH_RSS_IP */
+		flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
 		flow->rss.level = rss->level;
 		/* Added to array only in apply since we need the QP */
 		flow->actions |= MLX5_FLOW_ACTION_RSS;
diff --git a/drivers/net/mlx5/mlx5_flow_verbs.c b/drivers/net/mlx5/mlx5_flow_verbs.c
index 81bc39f..ae9042f 100644
--- a/drivers/net/mlx5/mlx5_flow_verbs.c
+++ b/drivers/net/mlx5/mlx5_flow_verbs.c
@@ -925,14 +925,19 @@ 
 				struct mlx5_flow *dev_flow)
 {
 	const struct rte_flow_action_rss *rss = action->conf;
+	const uint8_t *rss_key;
 	struct rte_flow *flow = dev_flow->flow;
 
 	if (flow->queue)
 		memcpy((*flow->queue), rss->queue,
 		       rss->queue_num * sizeof(uint16_t));
 	flow->rss.queue_num = rss->queue_num;
-	memcpy(flow->key, rss->key, MLX5_RSS_HASH_KEY_LEN);
-	flow->rss.types = rss->types;
+
+	/* NULL RSS key indicates default RSS key */
+	rss_key = !rss->key ? rss_hash_default_key : rss->key;
+	memcpy(flow->key, rss_key, MLX5_RSS_HASH_KEY_LEN);
+	/* RSS type 0 indicates default RSS type (ETH_RSS_IP) */
+	flow->rss.types = !rss->types ? ETH_RSS_IP : rss->types;
 	flow->rss.level = rss->level;
 	*action_flags |= MLX5_FLOW_ACTION_RSS;
 }
diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index ed993ea..36fc202 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -1783,10 +1783,6 @@  struct mlx5_hrxq *
 		rte_errno = ENOMEM;
 		return NULL;
 	}
-	if (!rss_key_len) {
-		rss_key_len = MLX5_RSS_HASH_KEY_LEN;
-		rss_key = rss_hash_default_key;
-	}
 #ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
 	qp = mlx5_glue->dv_create_qp
 		(priv->ctx,
@@ -1798,8 +1794,7 @@  struct mlx5_hrxq *
 				IBV_QP_INIT_ATTR_RX_HASH,
 			.rx_hash_conf = (struct ibv_rx_hash_conf){
 				.rx_hash_function = IBV_RX_HASH_FUNC_TOEPLITZ,
-				.rx_hash_key_len = rss_key_len ? rss_key_len :
-						   MLX5_RSS_HASH_KEY_LEN,
+				.rx_hash_key_len = rss_key_len,
 				.rx_hash_key = rss_key ?
 					       (void *)(uintptr_t)rss_key :
 					       rss_hash_default_key,
@@ -1824,8 +1819,7 @@  struct mlx5_hrxq *
 				IBV_QP_INIT_ATTR_RX_HASH,
 			.rx_hash_conf = (struct ibv_rx_hash_conf){
 				.rx_hash_function = IBV_RX_HASH_FUNC_TOEPLITZ,
-				.rx_hash_key_len = rss_key_len ? rss_key_len :
-						   MLX5_RSS_HASH_KEY_LEN,
+				.rx_hash_key_len = rss_key_len,
 				.rx_hash_key = rss_key ?
 					       (void *)(uintptr_t)rss_key :
 					       rss_hash_default_key,
@@ -1888,8 +1882,12 @@  struct mlx5_hrxq *
 	LIST_FOREACH(hrxq, &priv->hrxqs, next) {
 		struct mlx5_ind_table_ibv *ind_tbl;
 
+		if (!rss_key_len)
+			rss_key_len = MLX5_RSS_HASH_KEY_LEN;
 		if (hrxq->rss_key_len != rss_key_len)
 			continue;
+		if (!rss_key)
+			rss_key = rss_hash_default_key;
 		if (memcmp(hrxq->rss_key, rss_key, rss_key_len))
 			continue;
 		if (hrxq->hash_fields != hash_fields)
diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index c0fe879..6cc72ab 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -1785,7 +1785,7 @@  struct rte_flow_action_rss {
 	uint64_t types; /**< Specific RSS hash types (see ETH_RSS_*). */
 	uint32_t key_len; /**< Hash key length in bytes. */
 	uint32_t queue_num; /**< Number of entries in @p queue. */
-	const uint8_t *key; /**< Hash key. */
+	const uint8_t *key; /**< Hash key. NULL should indicate default key */
 	const uint16_t *queue; /**< Queue indices to use. */
 };