On Tue, May 19, 2026 at 12:34:14PM +0200, Thomas Monjalon 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: [email protected]
>
> Signed-off-by: Thomas Monjalon <[email protected]>
> ---
> v1: drop volatile keyword
> v2: make user an atomic variable
> v3: rename user as owner
> ---
> lib/eal/include/generic/rte_spinlock.h | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
Series-acked-by: Bruce Richardson <[email protected]>
