Re: [dpdk-stable] [PATCH 2/3] stack: add lock-free support indication

[Olivier Matz <olivier.matz@6wind.com>]

On Mon, Apr 12, 2021 at 10:29:00AM +0200, Stanislaw Kardach wrote:
> Currently it is impossible to detect programatically whether lock-free
> implementation of rte_stack is supported. One could check whether the
> header guard for lock-free stubs is defined (_RTE_STACK_LF_STUBS_H_) but
> that's an unstable implementation detail. Because of that currently all
> lock-free ring creations silently succeed (as long as the stack header
> is 16B long) which later leads to push and pop operations being NOPs.
> The observable effect is that stack_lf_autotest fails on platforms not
> supporting the lock-free. Instead it should just skip the lock-free test
> altogether.
> 
> This commit adds a new errno value (ENOTSUP) that may be returned by
> rte_stack_create() to indicate that a given combination of flags is not
> supported on a current platform.
> This is detected by checking a compile-time flag in the include logic in
> rte_stack_lf.h which may be used by applications to check the lock-free
> support at compile time.
> 
> Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
> Fixes: 7911ba0473e0 ("stack: enable lock-free implementation for aarch64")
> Cc: phil.yang@arm.com
> Cc: stable@dpdk.org

Acked-by: Olivier Matz <olivier.matz@6wind.com>