On 3/15/21 11:55 AM, Thomas Monjalon wrote:

15/03/2021 09:43, Andrew Rybchenko:

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On 3/15/21 10:54 AM, Thomas Monjalon wrote:

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15/03/2021 08:18, Andrew Rybchenko:

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On 3/12/21 8:46 PM, Thomas Monjalon wrote:

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--- a/lib/librte_ethdev/rte_flow.c
+++ b/lib/librte_ethdev/rte_flow.c

@@ -255,18 +255,19 @@ rte_flow_ops_get(uint16_t port_id, struct rte_flow_error *error)
 
 	if (unlikely(!rte_eth_dev_is_valid_port(port_id)))
 		code = ENODEV;
-	else if (unlikely(!dev->dev_ops->filter_ctrl ||
-			  dev->dev_ops->filter_ctrl(dev,
-						    RTE_ETH_FILTER_GENERIC,
-						    RTE_ETH_FILTER_GET,
-						    &ops) ||
-			  !ops))
-		code = ENOSYS;
+	else if (unlikely(dev->dev_ops->flow_ops_get == NULL))
+		code = ENOTSUP;

It is described as:
   -ENOTSUP: valid but unsupported rule specification (e.g.
   partial bit-masks are unsupported).
So, it looks different. May be it is really better to keep
ENOSYS.

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 	else
-		return ops;
-	rte_flow_error_set(error, code, RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
-			   NULL, rte_strerror(code));
-	return NULL;
+		code = dev->dev_ops->flow_ops_get(dev, &ops);
+	if (code == 0 && ops == NULL)
+		code = EACCES;

It looks something new. I think it should be mentioned in flow_ops_get
type documentation (similar to eth_promiscuous_enable_t) and
rte_flow_validate() etc functions
return values description.

It is an internal function used only in rte_flow.c.
The real consequence is to set rte_errno in a lot of rte_flow API.
Not sure there is a good way to document the code details.
Other codes are not documented in rte_flow.h

First of all it is a behaviour of the flow_ops_get callback and
driver developers should know that it is a legal to return 0 and
ops==NULL and know what it means.

The combination code 0 and ops NULL is not new.
Previously, it was returning ENOSYS.
I've just given a more meaningful error code: EACCES,
while replacing ENOSYS with ENOTSUP for the other case.

Yes, exactly. What I'm trying to say that it would be
helpful to make it a bit more transparent to PMD developers.
Yes, it was not documented before, I agree. I think it is
a good time to improve documentation.

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Second, it is visible as rte_flow_validate() (and other functions
which use rte_flow_ops_get()) return value value which has
special meaning. So, should be documented.

Yes, I should update the API doc where ENOSYS was mentioned.
Or probably better: I should keep the error code ENOSYS
and do not break API.
Preference?

Good question. I think we should not distinguish NULL callback
and NULL ops returned by not-NULL callback. So, I think
keeping ENOSYS is the best option here.