[PATCH 1/2] eal: fix constraints on stdatomic API

[Tyler Retzlaff]

On Mon, Dec 11, 2023 at 03:39:03PM +0800, Jie Hai wrote:
> The first parameter of rte_atomic_exchange_explicit() must be a
> pointer to _Atomic type. If run command "meson setup --werror
> -Denable_stdatomic=true build && ninja -C build", error will occur.
> Thia patch fixes it.
> 
> Fixes: 1ec6a845b5cb ("eal: use stdatomic API in public headers")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Jie Hai <haijie1 at huawei.com>
> ---
>  app/test/test_atomic.c               |  6 +++---
>  lib/eal/include/generic/rte_atomic.h | 12 ++++++------
>  2 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/app/test/test_atomic.c b/app/test/test_atomic.c
> index db07159e81ab..c3cb3ae0ea57 100644
> --- a/app/test/test_atomic.c
> +++ b/app/test/test_atomic.c
> @@ -347,9 +347,9 @@ typedef union {
>  const uint8_t CRC8_POLY = 0x91;
>  uint8_t crc8_table[256];
>  
> -volatile uint16_t token16;
> -volatile uint32_t token32;
> -volatile uint64_t token64;
> +volatile RTE_ATOMIC(uint16_t) token16;
> +volatile RTE_ATOMIC(uint32_t) token32;
> +volatile RTE_ATOMIC(uint64_t) token64;

subject to my comment below, volatile qualification can be removed.

>  
>  static void
>  build_crc8_table(void)
> diff --git a/lib/eal/include/generic/rte_atomic.h b/lib/eal/include/generic/rte_atomic.h
> index 0e639dad76a4..38c3b41f9c68 100644
> --- a/lib/eal/include/generic/rte_atomic.h
> +++ b/lib/eal/include/generic/rte_atomic.h
> @@ -207,11 +207,11 @@ rte_atomic16_cmpset(volatile uint16_t *dst, uint16_t exp, uint16_t src)
>   *   The original value at that location
>   */
>  static inline uint16_t
> -rte_atomic16_exchange(volatile uint16_t *dst, uint16_t val);
> +rte_atomic16_exchange(volatile RTE_ATOMIC(uint16_t) *dst, uint16_t val);

the existing rte_atomicNN (the old non-standard ones) are deprecated and will
be eventually removed so there isn't a lot of value in churning their
signatures to wrap the rte_stdatomic macros.

the right thing to do here to just change the calling code to use the generic
rte_stdatomic macros directly so we can eventually remove
rte_atomicNN_xxx.

ty