[dpdk-dev] [PATCH v4] eventdev: add errno-style return values

[Eads, Gage]

>  -----Original Message-----
>  From: Jerin Jacob [mailto:jerin.jacob at caviumnetworks.com]
>  Sent: Tuesday, March 21, 2017 6:06 AM
>  To: Eads, Gage <gage.eads at intel.com>
>  Cc: dev at dpdk.org; Richardson, Bruce <bruce.richardson at intel.com>;
>  hemant.agrawal at nxp.com; Van Haaren, Harry <harry.van.haaren at intel.com>;
>  nipun.gupta at nxp.com
>  Subject: Re: [PATCH v4] eventdev: add errno-style return values
>  
>  On Fri, Mar 17, 2017 at 09:51:28AM -0500, Gage Eads wrote:
>  > From: "Eads, Gage" <gage.eads at 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 at 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
>  >
>  >  lib/librte_eventdev/rte_eventdev.h | 40
>  > +++++++++++++++++++++++++++++++++++---
>  >  1 file changed, 37 insertions(+), 3 deletions(-)
>  >
>  > diff --git a/lib/librte_eventdev/rte_eventdev.h
>  > b/lib/librte_eventdev/rte_eventdev.h
>  > index 2b30a35..a45c81a 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 */
>  >
>  > @@ -1118,9 +1119,14 @@ 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.
>  
>  Some reason you haven't addressed the comments in v2.i.e add a note that -
>  ENOSPC applicable only for *closed system*
>  
>  http://dpdk.org/ml/archives/dev/2017-March/060352.html
>  

Will fix.

>  
>  >   * @see rte_event_port_enqueue_depth()
>  >   */
>  >  static inline uint16_t
>  > @@ -1129,6 +1135,20 @@ 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
>  
>  Some reason you haven't addressed the comments in v2.i.e Not fixed the build
>  issue.
>  http://dpdk.org/ml/archives/dev/2017-March/060352.html
>  
>  You can reproduce it by setting CONFIG_RTE_LIBRTE_EVENTDEV_DEBUG=y in
>  common config.
>  
>  We have two approaches to fix it
>  1/ Pollute lib/librte_eventdev/rte_eventdev.h header with implementation
>  specific header files
>  
>  Or
>  
>  2/ Have neat pmd debug common function in rte_eventdev_pmd.h.Let all PMD
>  driver call it by including rte_eventdev_pmd.h
>  

I'd prefer to avoid the issue by dropping the debug message and RTE_EVENTDEV_DETACHED, like so:

#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

What do you think?