Re: [dpdk-dev] [PATCH v3 2/4] bbdev: use C11 atomic builtins for device processing counter

["Chautru, Nicolas" <nicolas.chautru@intel.com>]

Hi Phil, 
Naïve question but the deprecation document was stating that "DPDK will adopt C11 atomic operations semantics and provide wrappers using C11 atomic built-ins."
Here you are using directly the C11 atomic built-ins and not providing and using a DPDK wrapper. 
Wasn't the intent to have a new rte_... wrapper here? Ie. the same way as the __sync_fetch_and_add() were called before behind the rte_atomicNN_XX wrapper. 

Thanks
Nic


> -----Original Message-----
> From: Phil Yang <phil.yang@arm.com>
> Sent: Wednesday, September 23, 2020 10:39 PM
> To: dev@dpdk.org; david.marchand@redhat.com; Chautru, Nicolas
> <nicolas.chautru@intel.com>; Hunt, David <david.hunt@intel.com>
> Cc: Ruifeng.Wang@arm.com; Honnappa.Nagarahalli@arm.com;
> nd@arm.com
> Subject: [PATCH v3 2/4] bbdev: use C11 atomic builtins for device processing
> counter
> 
> Since rte_atomicXX APIs are not allowed to be used, use C11 atomic builtins
> for device processing counter.
> 
> Signed-off-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> ---
>  lib/librte_bbdev/rte_bbdev.c | 5 +++--
>  lib/librte_bbdev/rte_bbdev.h | 4 +---
>  2 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_bbdev/rte_bbdev.c b/lib/librte_bbdev/rte_bbdev.c
> index a4fdb69..5ba891c 100644
> --- a/lib/librte_bbdev/rte_bbdev.c
> +++ b/lib/librte_bbdev/rte_bbdev.c
> @@ -210,7 +210,7 @@ rte_bbdev_allocate(const char *name)
>  		return NULL;
>  	}
> 
> -	rte_atomic16_inc(&bbdev->data->process_cnt);
> +	__atomic_add_fetch(&bbdev->data->process_cnt, 1,
> __ATOMIC_RELAXED);
>  	bbdev->data->dev_id = dev_id;
>  	bbdev->state = RTE_BBDEV_INITIALIZED;
> 
> @@ -252,7 +252,8 @@ rte_bbdev_release(struct rte_bbdev *bbdev)
>  	}
> 
>  	/* clear shared BBDev Data if no process is using the device anymore
> */
> -	if (rte_atomic16_dec_and_test(&bbdev->data->process_cnt))
> +	if (__atomic_sub_fetch(&bbdev->data->process_cnt, 1,
> +			      __ATOMIC_RELAXED) == 0)
>  		memset(bbdev->data, 0, sizeof(*bbdev->data));
> 
>  	memset(bbdev, 0, sizeof(*bbdev));
> diff --git a/lib/librte_bbdev/rte_bbdev.h b/lib/librte_bbdev/rte_bbdev.h
> index 5729137..7017124 100644
> --- a/lib/librte_bbdev/rte_bbdev.h
> +++ b/lib/librte_bbdev/rte_bbdev.h
> @@ -33,7 +33,6 @@ extern "C" {
>  #include <string.h>
> 
>  #include <rte_compat.h>
> -#include <rte_atomic.h>
>  #include <rte_bus.h>
>  #include <rte_cpuflags.h>
>  #include <rte_memory.h>
> @@ -426,8 +425,7 @@ struct rte_bbdev_data {
>  	uint16_t dev_id;  /**< Device ID */
>  	int socket_id;  /**< NUMA socket that device is on */
>  	bool started;  /**< Device run-time state */
> -	/** Counter of processes using the device */
> -	rte_atomic16_t process_cnt;
> +	uint16_t process_cnt;  /** Counter of processes using the device */
>  };
> 
>  /* Forward declarations */
> --
> 2.7.4