RDMA/counter: Add an is_disabled field in struct rdma_hw_stats

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.

Link: https://lore.kernel.org/r/20211008122439.166063-6-markzhang@nvidia.com
Signed-off-by: Aharon Landau <aharonl@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

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,

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 +3017,10 @@ 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);
 }
 EXPORT_SYMBOL(rdma_free_hw_stats_struct);

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[];
 };