> -----Original Message-----
> From: dev <dev-boun...@dpdk.org> On Behalf Of Fredrik A Lindgren
> Sent: Monday, February 1, 2021 9:22 AM
> To: dev@dpdk.org
> Subject: [dpdk-dev] Question: typedef of eventdev_info_get_t bug?
>
> While debugging a driver I was looking at the code and realized that
> eventdev_info_get_t typedef is defined with void return value but
> documentation
> for it says it should return 0
Hi Fredrik,
Be aware that your snippets of code below is mixing Event-dev and Eth-dev.
This is likely the cause of confusion.
> lib/librte_eventdev/eventdev_pmd.h:
>
> ...
> * @return
> * Returns 0 on success
> */
> typedef void (*eventdev_info_get_t)(struct rte_eventdev *dev,
> struct
> rte_event_dev_info *dev_info);
> ...
> struct rte_eventdev_ops {
> eventdev_info_get_t dev_infos_get;
> /**< Get device info. */
> ...
>
> While return value from it is used in lib/librte_ethdev/rte_ethdev.c:
>
> int
> rte_eth_dev_info_get(uint16_t port_id, struct rte_eth_dev_info *dev_info)
> ...
> diag = (*dev->dev_ops->dev_infos_get)(dev, dev_info);
> if (diag != 0) {
> ...
At the Eventdev layer, info_get() can return int (particularly 0 on success, or
-ERROR values).
At the Eventdev PMD layer, info_get() has a return void (the PMD cannot
indicate failure on providing its info)
Hence, the info_get() typedef (for the PMD) is void, but the Eventdev layer
itself checks some dev_id values
etc, and can return -EINVAL or -ENOTSUP in case the PMD doesn't support
info_get().
> Driver I'm debugging doesn't have any return statement in it's dev_infos_get
> function which seems to cause it to have "result" of last operation done in
> that
> function as return value.
> Though this behavior may be compiler specific but it should probably be
> clarified and
> updated (change prototype of stop using return value) to avoid issue with it.
Perhaps provide some more detail on Eventdev/Ethdev that you're debugging a
driver on,
provide some links to specific parts of the code? It seems like (from Eventdev
anyway) its
meant to work this way.
> Br,
> Fredrik
Regards, -Harry
