ethdev: expose flow API error helper

rte_flow_error_set() is a convenient helper to initialize error objects.

Since there is no fundamental reason to prevent applications from using it,
expose it through the public interface after modifying its return value
from positive to negative. This is done for consistency with the rest of
the public interface.

Documentation is updated accordingly.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>

doc/guides/prog_guide/rte_flow.rst

@@ -1695,6 +1695,25 @@ freed by the application, however its pointer can be considered valid only
 as long as its associated DPDK port remains configured. Closing the
 underlying device or unloading the PMD invalidates it.
 
+Helpers
+-------
+
+Error initializer
+~~~~~~~~~~~~~~~~~
+
+.. code-block:: c
+
+   static inline int
+   rte_flow_error_set(struct rte_flow_error *error,
+                      int code,
+                      enum rte_flow_error_type type,
+                      const void *cause,
+                      const char *message);
+
+This function initializes ``error`` (if non-NULL) with the provided
+parameters and sets ``rte_errno`` to ``code``. A negative error ``code`` is
+then returned.
+
 Caveats
 -------
 
@@ -1760,13 +1779,11 @@ the legacy filtering framework, which should eventually disappear.
   whatsoever). They only make sure these callbacks are non-NULL or return
   the ``ENOSYS`` (function not supported) error.
 
-This interface additionally defines the following helper functions:
+This interface additionally defines the following helper function:
 
 - ``rte_flow_ops_get()``: get generic flow operations structure from a
   port.
 
-- ``rte_flow_error_set()``: initialize generic flow error structure.
-
 More will be added over time.
 
 Device compatibility

drivers/net/mlx4/mlx4_flow.c

@@ -955,9 +955,9 @@ mlx4_flow_isolate(struct rte_eth_dev *dev,
 		mlx4_mac_addr_del(priv);
 	} else if (mlx4_mac_addr_add(priv) < 0) {
 		priv->isolated = 1;
-		return -rte_flow_error_set(error, rte_errno,
-					   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
-					   NULL, "cannot leave isolated mode");
+		return rte_flow_error_set(error, rte_errno,
+					  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+					  NULL, "cannot leave isolated mode");
 	}
 	return 0;
 }

drivers/net/tap/tap_flow.c

@@ -1462,7 +1462,7 @@ tap_flow_isolate(struct rte_eth_dev *dev,
 	return 0;
 error:
 	pmd->flow_isolate = 0;
-	return -rte_flow_error_set(
+	return rte_flow_error_set(
 		error, ENOTSUP, RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
 		"TC rule creation failed");
 }

lib/librte_ether/rte_ethdev_version.map

@@ -193,5 +193,6 @@ DPDK_17.11 {
 
 	rte_eth_dev_pool_ops_supported;
 	rte_eth_dev_reset;
+	rte_flow_error_set;
 
 } DPDK_17.08;

lib/librte_ether/rte_flow.c

@@ -145,9 +145,9 @@ rte_flow_validate(uint16_t port_id,
 		return -rte_errno;
 	if (likely(!!ops->validate))
 		return ops->validate(dev, attr, pattern, actions, error);
-	return -rte_flow_error_set(error, ENOSYS,
-				   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
-				   NULL, rte_strerror(ENOSYS));
+	return rte_flow_error_set(error, ENOSYS,
+				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+				  NULL, rte_strerror(ENOSYS));
 }
 
 /* Create a flow rule on a given port. */
@@ -183,9 +183,9 @@ rte_flow_destroy(uint16_t port_id,
 		return -rte_errno;
 	if (likely(!!ops->destroy))
 		return ops->destroy(dev, flow, error);
-	return -rte_flow_error_set(error, ENOSYS,
-				   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
-				   NULL, rte_strerror(ENOSYS));
+	return rte_flow_error_set(error, ENOSYS,
+				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+				  NULL, rte_strerror(ENOSYS));
 }
 
 /* Destroy all flow rules associated with a port. */
@@ -200,9 +200,9 @@ rte_flow_flush(uint16_t port_id,
 		return -rte_errno;
 	if (likely(!!ops->flush))
 		return ops->flush(dev, error);
-	return -rte_flow_error_set(error, ENOSYS,
-				   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
-				   NULL, rte_strerror(ENOSYS));
+	return rte_flow_error_set(error, ENOSYS,
+				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+				  NULL, rte_strerror(ENOSYS));
 }
 
 /* Query an existing flow rule. */
@@ -220,9 +220,9 @@ rte_flow_query(uint16_t port_id,
 		return -rte_errno;
 	if (likely(!!ops->query))
 		return ops->query(dev, flow, action, data, error);
-	return -rte_flow_error_set(error, ENOSYS,
-				   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
-				   NULL, rte_strerror(ENOSYS));
+	return rte_flow_error_set(error, ENOSYS,
+				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+				  NULL, rte_strerror(ENOSYS));
 }
 
 /* Restrict ingress traffic to the defined flow rules. */
@@ -238,9 +238,28 @@ rte_flow_isolate(uint16_t port_id,
 		return -rte_errno;
 	if (likely(!!ops->isolate))
 		return ops->isolate(dev, set, error);
-	return -rte_flow_error_set(error, ENOSYS,
-				   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
-				   NULL, rte_strerror(ENOSYS));
+	return rte_flow_error_set(error, ENOSYS,
+				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+				  NULL, rte_strerror(ENOSYS));
+}
+
+/* Initialize flow error structure. */
+int
+rte_flow_error_set(struct rte_flow_error *error,
+		   int code,
+		   enum rte_flow_error_type type,
+		   const void *cause,
+		   const char *message)
+{
+	if (error) {
+		*error = (struct rte_flow_error){
+			.type = type,
+			.cause = cause,
+			.message = message,
+		};
+	}
+	rte_errno = code;
+	return -code;
 }
 
 /** Compute storage space needed by item specification. */

lib/librte_ether/rte_flow.h

@@ -1321,6 +1321,30 @@ rte_flow_query(uint16_t port_id,
 int
 rte_flow_isolate(uint16_t port_id, int set, struct rte_flow_error *error);
 
+/**
+ * Initialize flow error structure.
+ *
+ * @param[out] error
+ *   Pointer to flow error structure (may be NULL).
+ * @param code
+ *   Related error code (rte_errno).
+ * @param type
+ *   Cause field and error types.
+ * @param cause
+ *   Object responsible for the error.
+ * @param message
+ *   Human-readable error message.
+ *
+ * @return
+ *   Negative error code (errno value) and rte_errno is set.
+ */
+int
+rte_flow_error_set(struct rte_flow_error *error,
+		   int code,
+		   enum rte_flow_error_type type,
+		   const void *cause,
+		   const char *message);
+
 /**
  * Generic flow representation.
  *

lib/librte_ether/rte_flow_driver.h

@@ -45,7 +45,6 @@
 
 #include <stdint.h>
 
-#include <rte_errno.h>
 #include "rte_ethdev.h"
 #include "rte_flow.h"
 
@@ -127,43 +126,6 @@ struct rte_flow_ops {
 		 struct rte_flow_error *);
 };
 
-/**
- * Initialize generic flow error structure.
- *
- * This function also sets rte_errno to a given value.
- *
- * @param[out] error
- *   Pointer to flow error structure (may be NULL).
- * @param code
- *   Related error code (rte_errno).
- * @param type
- *   Cause field and error types.
- * @param cause
- *   Object responsible for the error.
- * @param message
- *   Human-readable error message.
- *
- * @return
- *   Error code.
- */
-static inline int
-rte_flow_error_set(struct rte_flow_error *error,
-		   int code,
-		   enum rte_flow_error_type type,
-		   const void *cause,
-		   const char *message)
-{
-	if (error) {
-		*error = (struct rte_flow_error){
-			.type = type,
-			.cause = cause,
-			.message = message,
-		};
-	}
-	rte_errno = code;
-	return code;
-}
-
 /**
  * Get generic flow operations structure from a port.
  *