[PATCH] vhost: fix misleading log when setting max queue num

[Kevin Traynor]

On 09/01/2025 14:31, Maxime Coquelin wrote:
> rte_vhost_driver_set_max_queue_num API returns early when
> called for a Vhost-user device, as this API is intended to
> limit the maximum number of queue pairs supported by VDUSE
> devices. However, a log mentioning the maximim number of
> queue pairs is being set is emitted unconditionally, which
> may confuse the end user.
> 
> This patch moves this log after the backend type is
> checked, so that it is only called with VDUSE backends.
> The check on the requested value is also moved at the same
> place.
> 
> Fixes: e1808999d36b ("vhost: restrict set max queue pair API to VDUSE")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/vhost/socket.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 

Thanks, this will make it easier for vhost-user users. One nit below,

Acked-by: Kevin Traynor <ktraynor at redhat.com>

> diff --git a/lib/vhost/socket.c b/lib/vhost/socket.c
> index d29d15494c..07247907b0 100644
> --- a/lib/vhost/socket.c
> +++ b/lib/vhost/socket.c
> @@ -844,13 +844,6 @@ rte_vhost_driver_set_max_queue_num(const char *path, uint32_t max_queue_pairs)
>  	struct vhost_user_socket *vsocket;
>  	int ret = 0;
>  
> -	VHOST_CONFIG_LOG(path, INFO, "Setting max queue pairs to %u", max_queue_pairs);
> -
> -	if (max_queue_pairs > VHOST_MAX_QUEUE_PAIRS) {
> -		VHOST_CONFIG_LOG(path, ERR, "Library only supports up to %u queue pairs",
> -				VHOST_MAX_QUEUE_PAIRS);
> -		return -1;
> -	}
>  

you can remove the extra blank line here

>  	pthread_mutex_lock(&vhost_user.mutex);
>  	vsocket = find_vhost_user_socket(path);
> @@ -872,6 +865,15 @@ rte_vhost_driver_set_max_queue_num(const char *path, uint32_t max_queue_pairs)
>  		goto unlock_exit;
>  	}
>  
> +	VHOST_CONFIG_LOG(path, INFO, "Setting max queue pairs to %u", max_queue_pairs);
> +
> +	if (max_queue_pairs > VHOST_MAX_QUEUE_PAIRS) {
> +		VHOST_CONFIG_LOG(path, ERR, "Library only supports up to %u queue pairs",
> +				VHOST_MAX_QUEUE_PAIRS);
> +		ret = -1;
> +		goto unlock_exit;
> +	}
> +
>  	vsocket->max_queue_pairs = max_queue_pairs;
>  
>  unlock_exit: