Re: [PATCH v3 1/3] spinlock: remove volatile qualifier

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 19 May 2026 12:34:14 +0200
Thomas Monjalon <thomas@monjalon.net> wrote:

> When compiling with C++20 standard requirement (default in GCC 16),
> the increment and decrement of volatile variables are rejected:
> 
> rte_spinlock.h:241:14: error:
> 	'++' expression of 'volatile'-qualified type is deprecated
> rte_spinlock.h:252:21: error:
> 	'--' expression of 'volatile'-qualified type is deprecated
> rte_spinlock.h:278:14: error:
> 	'++' expression of 'volatile'-qualified type is deprecated
> 
> The count field of rte_spinlock_recursive_t
> does not need the volatile qualifier
> because it is only accessed by the thread holding the lock,
> which already provides the necessary memory ordering.
> 
> The user field can be accessed outside of the lock,
> so it must handled as a C11 atomic variable.
> The name is also changed from user to owner.
> It will break if an application is accessing this field directly,
> which should never happen.
> 
> Fixes: af75078fece3 ("first public release")
> Cc: stable@dpdk.org
> 
> Signed

Series-acked-by: Stephen Hemminger <stephen@networkplumber.org>