Subject: Re: [PATCH rdma-next v3 05/13] RDMA/counter: Add an is_disabled field in struct rdma_hw_stats

From: Leon Romanovsky <[email-masked]>
Date: Wed, 6 Oct 2021 14:49:07 +0300

On Wed, Oct 06, 2021 at 12:52:08PM +0300, Leon Romanovsky wrote:
> From: Aharon Landau <[email-masked]>
> 
> Add a bitmap in rdma_hw_stat structure, with each bit indicates whether
> the corresponding counter is currently disabled or not. By default
> hwcounters are enabled.
> 
> Signed-off-by: Aharon Landau <[email-masked]>
> Reviewed-by: Mark Zhang <[email-masked]>
> Signed-off-by: Leon Romanovsky <[email-masked]>
> ---
>  drivers/infiniband/core/nldev.c | 11 ++++++++++-
>  drivers/infiniband/core/verbs.c | 10 ++++++++++
>  include/rdma/ib_verbs.h         |  3 +++
>  3 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> index 3f6b98a87566..67519730b1ac 100644
> --- a/drivers/infiniband/core/nldev.c
> +++ b/drivers/infiniband/core/nldev.c
> @@ -968,15 +968,21 @@ static int fill_stat_counter_hwcounters(struct sk_buff *msg,
>  	if (!table_attr)
>  		return -EMSGSIZE;
>  
> -	for (i = 0; i < st->num_counters; i++)
> +	mutex_lock(&st->lock);
> +	for (i = 0; i < st->num_counters; i++) {
> +		if (test_bit(i, st->is_disabled))
> +			continue;
>  		if (rdma_nl_stat_hwcounter_entry(msg, st->descs[i].name,
>  						 st->value[i]))
>  			goto err;
> +	}
> +	mutex_unlock(&st->lock);
>  
>  	nla_nest_end(msg, table_attr);
>  	return 0;
>  
>  err:
> +	mutex_unlock(&st->lock);
>  	nla_nest_cancel(msg, table_attr);
>  	return -EMSGSIZE;
>  }
> @@ -2104,6 +2110,9 @@ static int stat_get_doit_default_counter(struct sk_buff *skb,
>  		goto err_stats;
>  	}
>  	for (i = 0; i < num_cnts; i++) {
> +		if (test_bit(i, stats->is_disabled))
> +			continue;
> +
>  		v = stats->value[i] +
>  			rdma_counter_get_hwstat_value(device, port, i);
>  		if (rdma_nl_stat_hwcounter_entry(msg,
> diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
> index c3319a7584a2..d957b23a0e23 100644
> --- a/drivers/infiniband/core/verbs.c
> +++ b/drivers/infiniband/core/verbs.c
> @@ -2994,11 +2994,20 @@ struct rdma_hw_stats *rdma_alloc_hw_stats_struct(
>  	if (!stats)
>  		return NULL;
>  
> +	stats->is_disabled = kcalloc(BITS_TO_LONGS(num_counters),
> +				     sizeof(*stats->is_disabled), GFP_KERNEL);
> +	if (!stats->is_disabled)
> +		goto err;
> +
>  	stats->descs = descs;
>  	stats->num_counters = num_counters;
>  	stats->lifespan = msecs_to_jiffies(lifespan);
>  
>  	return stats;
> +
> +err:
> +	kfree(stats);
> +	return NULL;
>  }
>  EXPORT_SYMBOL(rdma_alloc_hw_stats_struct);
>  
> @@ -3008,6 +3017,7 @@ EXPORT_SYMBOL(rdma_alloc_hw_stats_struct);
>   */
>  void rdma_free_hw_stats_struct(struct rdma_hw_stats *stats)
>  {
> +	kfree(stats->is_disabled);
>  	kfree(stats);

Jason,

This hunk needs to be the following for the representors case. Can you
please fix it locally?

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index d957b23a0e23..e9e042b31386 100644
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -3017,6 +3017,9 @@ EXPORT_SYMBOL(rdma_alloc_hw_stats_struct);
  */
 void rdma_free_hw_stats_struct(struct rdma_hw_stats *stats)
 {
+       if (!stats)
+               return;
+
        kfree(stats->is_disabled);
        kfree(stats);
 }

Thanks

>  }
>  EXPORT_SYMBOL(rdma_free_hw_stats_struct);
> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> index 938c0c0a1c19..ae467365706b 100644
> --- a/include/rdma/ib_verbs.h
> +++ b/include/rdma/ib_verbs.h
> @@ -565,6 +565,8 @@ struct rdma_stat_desc {
>   *   their own value during their allocation routine.
>   * @descs - Array of pointers to static descriptors used for the counters
>   *   in directory.
> + * @is_disabled - A bitmap to indicate each counter is currently disabled
> + *   or not.
>   * @num_counters - How many hardware counters there are.  If name is
>   *   shorter than this number, a kernel oops will result.  Driver authors
>   *   are encouraged to leave BUILD_BUG_ON(ARRAY_SIZE(@name) < num_counters)
> @@ -577,6 +579,7 @@ struct rdma_hw_stats {
>  	unsigned long	timestamp;
>  	unsigned long	lifespan;
>  	const struct rdma_stat_desc *descs;
> +	unsigned long	*is_disabled;
>  	int		num_counters;
>  	u64		value[];
>  };
> -- 
> 2.31.1
>