Re: [rdma-core PATCH] providers/rxe: Replace '%' with '&' in check_qp_queue_full()

["yangx.jy@fujitsu.com" <yangx.jy@fujitsu.com>]

On 2022/1/11 9:41, Xiao Yang wrote:
> The expression "cons == ((qp->cur_index + 1) % q->index_mask)" mistakenly
> assumes the queue is full when qp->cur_index is equal to "maximum - 1"
> (maximum is correct).
Hi All,

The commit message seems inappropriate so I will resend this patch.

Best Regards,
Xiao Yang
> For example:
> If cons and qp->cur_index are 0 and q->index_mask is 1, check_qp_queue_full()
> reports ENOSPC.
>
> Fixes: 1a894ca10105 ("Providers/rxe: Implement ibv_create_qp_ex verb")
> Signed-off-by: Xiao Yang <yangx.jy@fujitsu.com>
> ---
>  providers/rxe/rxe_queue.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/providers/rxe/rxe_queue.h b/providers/rxe/rxe_queue.h
> index 6de8140c..708e76ac 100644
> --- a/providers/rxe/rxe_queue.h
> +++ b/providers/rxe/rxe_queue.h
> @@ -205,7 +205,7 @@ static inline int check_qp_queue_full(struct rxe_qp *qp)
>  	if (qp->err)
>  		goto err;
>  
> -	if (cons == ((qp->cur_index + 1) % q->index_mask))
> +	if (cons == ((qp->cur_index + 1) & q->index_mask))
>  		qp->err = ENOSPC;
>  err:
>  	return qp->err;