[dpdk-dev] [PATCH v6] eventdev: add errno-style return values

[Gage Eads <gage.eads@intel.com>]

From: "Eads, Gage" <gage.eads@intel.com>

This commit adds rte_errno return values to rte_event_enqueue_burst() and
rte_event_dequeue_burst().

These return values allows user software to differentiate between an
invalid argument (such as an invalid queue_id or sched_type in an enqueued
event) and backpressure from the event device.

The port and device ID checks are placed in RTE_LIBRTE_EVENTDEV_DEBUG
header guards to avoid the performance hit in non-debug execution.

Signed-off-by: Gage Eads <gage.eads@intel.com>
---
Changes for v2:
  - Remove rte_errno initialization
Changes for v3:
  - Fix checkpatch and check-git-log.sh errors
Changes for v4:
  - v3 was incorrectly based on v1, v4 is instead based on v2's changes
Changes for v5:
  - Clarify -ENOSPC description and fix compilation errors
Changes for v6:
  - Fixed html doc rendering of bullet points for errno values

 lib/librte_eventdev/rte_eventdev.h | 37 ++++++++++++++++++++++++++++++++++---
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/lib/librte_eventdev/rte_eventdev.h b/lib/librte_eventdev/rte_eventdev.h
index 5ce2f33..9971937 100644
--- a/lib/librte_eventdev/rte_eventdev.h
+++ b/lib/librte_eventdev/rte_eventdev.h
@@ -245,6 +245,7 @@ extern "C" {
 
 #include <rte_common.h>
 #include <rte_memory.h>
+#include <rte_errno.h>
 
 struct rte_mbuf; /* we just use mbuf pointers; no need to include rte_mbuf.h */
 
@@ -1119,9 +1120,15 @@ rte_event_schedule(uint8_t dev_id)
  *   The number of event objects actually enqueued on the event device. The
  *   return value can be less than the value of the *nb_events* parameter when
  *   the event devices queue is full or if invalid parameters are specified in a
- *   *rte_event*. If return value is less than *nb_events*, the remaining events
- *   at the end of ev[] are not consumed,and the caller has to take care of them
- *
+ *   *rte_event*. If the return value is less than *nb_events*, the remaining
+ *   events at the end of ev[] are not consumed and the caller has to take care
+ *   of them, and rte_errno is set accordingly. Possible errno values include:
+ *   - -EINVAL  The port ID is invalid, device ID is invalid, an event's queue
+ *              ID is invalid, or an event's sched type doesn't match the
+ *              capabilities of the destination queue.
+ *   - -ENOSPC  The event port was backpressured and unable to enqueue
+ *              one or more events. This error code is only applicable to
+ *              closed systems.
  * @see rte_event_port_enqueue_depth()
  */
 static inline uint16_t
@@ -1130,6 +1137,18 @@ rte_event_enqueue_burst(uint8_t dev_id, uint8_t port_id,
 {
 	struct rte_eventdev *dev = &rte_eventdevs[dev_id];
 
+#ifdef RTE_LIBRTE_EVENTDEV_DEBUG
+	if (dev_id >= RTE_EVENT_MAX_DEVS || !rte_eventdevs[dev_id].attached) {
+		rte_errno = -EINVAL;
+		return 0;
+	}
+
+	if (port_id >= dev->data->nb_ports) {
+		rte_errno = -EINVAL;
+		return 0;
+	}
+#endif
+
 	/*
 	 * Allow zero cost non burst mode routine invocation if application
 	 * requests nb_events as const one
@@ -1240,6 +1259,18 @@ rte_event_dequeue_burst(uint8_t dev_id, uint8_t port_id, struct rte_event ev[],
 {
 	struct rte_eventdev *dev = &rte_eventdevs[dev_id];
 
+#ifdef RTE_LIBRTE_EVENTDEV_DEBUG
+	if (dev_id >= RTE_EVENT_MAX_DEVS || !rte_eventdevs[dev_id].attached) {
+		rte_errno = -EINVAL;
+		return 0;
+	}
+
+	if (port_id >= dev->data->nb_ports) {
+		rte_errno = -EINVAL;
+		return 0;
+	}
+#endif
+
 	/*
 	 * Allow zero cost non burst mode routine invocation if application
 	 * requests nb_events as const one
-- 
2.7.4