RE: [PATCH] eventdev: fix alignment padding

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Sivaprasad Tummala [mailto:sivaprasad.tummala@amd.com]
> Sent: Tuesday, 18 April 2023 12.46
> 
> fixed the padding required to align to cacheline size.
> 
> Fixes: 54f17843a887 ("eventdev: add port maintenance API")
> Cc: mattias.ronnblom@ericsson.com
> 
> Signed-off-by: Sivaprasad Tummala <sivaprasad.tummala@amd.com>
> ---
>  lib/eventdev/rte_eventdev_core.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/eventdev/rte_eventdev_core.h
> b/lib/eventdev/rte_eventdev_core.h
> index c328bdbc82..c27a52ccc0 100644
> --- a/lib/eventdev/rte_eventdev_core.h
> +++ b/lib/eventdev/rte_eventdev_core.h
> @@ -65,7 +65,7 @@ struct rte_event_fp_ops {
>  	/**< PMD Tx adapter enqueue same destination function. */
>  	event_crypto_adapter_enqueue_t ca_enqueue;
>  	/**< PMD Crypto adapter enqueue function. */
> -	uintptr_t reserved[6];
> +	uintptr_t reserved[5];
>  } __rte_cache_aligned;

This fix changes the size (reduces it by one cache line) of the elements in the public rte_event_fp_ops array, and thus breaks the ABI.

BTW, the patch it fixes, which was dated November 2021, also broke the ABI.

> 
>  extern struct rte_event_fp_ops rte_event_fp_ops[RTE_EVENT_MAX_DEVS];
> --
> 2.34.1