[PATCH net-next v2 04/16] devlink: Add reload stats

[Moshe Shemesh]

Add reload stats to hold the history per reload action type and limit.

For example, the number of times fw_activate has been performed on this
device since the driver module was added or if the firmware activation
was performed with or without reset.

Add devlink notification on stats update.

Expose devlink reload stats to the user through devlink dev get command.

Examples:
$ devlink dev show
pci/0000:82:00.0:
  stats:
      reload:
        driver_reinit 2 fw_activate 1 fw_activate_no_reset 0
pci/0000:82:00.1:
  stats:
      reload:
        driver_reinit 1 fw_activate 0 fw_activate_no_reset 0

$ devlink dev show -jp
{
    "dev": {
        "pci/0000:82:00.0": {
            "stats": {
                "reload": {
                    "driver_reinit": 2,
                    "fw_activate": 1,
                    "fw_activate_no_reset": 0
                }
            }
        },
        "pci/0000:82:00.1": {
            "stats": {
                "reload": {
                    "driver_reinit": 1,
                    "fw_activate": 0,
                    "fw_activate_no_reset": 0
                }
            }
        }
    }
}

Signed-off-by: Moshe Shemesh <moshe@xxxxxxxxxxxx>
---
v1 -> v2:
- Remove limit check from __devlink_reload_stats_update()
- Move definition that belongs to next patch
- Add devlink_dev_stats structure definition
- Use for_each_set_bit
- Combine nla_put in one condition
RFCv5 -> v1:
- Changed the stats output structure, have 2 stats, one for local and
one for remote
- Resplit this patch and the next one by remote/local reload stast
instead of set/get reload stats
- Add helper function devlink_reload_stats_put()
RFCv4 -> RFCv5:
- Add separate reload action stats for updating on remote actions
- Protect from updating remote actions stats during reload_down()/up()
RFCv3 -> RFCv4:
- Renamed reload_actions_cnts to reload_action_stats
- Add devlink notifications on stats update
- Renamed devlink_reload_actions_implicit_actions_performed() and add
  function comment in code
RFCv2 -> RFCv3:
- New patch
---
 include/net/devlink.h        |  8 ++++
 include/uapi/linux/devlink.h |  6 +++
 net/core/devlink.c           | 90 ++++++++++++++++++++++++++++++++++++
 3 files changed, 104 insertions(+)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 9f5c37c391f8..d091c6ba82ce 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -20,6 +20,13 @@
 #include <uapi/linux/devlink.h>
 #include <linux/xarray.h>
 
+#define DEVLINK_RELOAD_STATS_ARRAY_SIZE \
+	(__DEVLINK_RELOAD_LIMIT_MAX * __DEVLINK_RELOAD_ACTION_MAX)
+
+struct devlink_dev_stats {
+	u32 reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
+};
+
 struct devlink_ops;
 
 struct devlink {
@@ -38,6 +45,7 @@ struct devlink {
 	struct list_head trap_policer_list;
 	const struct devlink_ops *ops;
 	struct xarray snapshot_ids;
+	struct devlink_dev_stats stats;
 	struct device *dev;
 	possible_net_t _net;
 	struct mutex lock; /* Serializes access to devlink instance specific objects such as
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index a0b8e24236c0..6f4cdb95eaee 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -520,6 +520,12 @@ enum devlink_attr {
 	DEVLINK_ATTR_RELOAD_ACTIONS_PERFORMED,	/* bitfield32 */
 	DEVLINK_ATTR_RELOAD_LIMITS,		/* bitfield32 */
 
+	DEVLINK_ATTR_DEV_STATS,			/* nested */
+	DEVLINK_ATTR_RELOAD_STATS,		/* nested */
+	DEVLINK_ATTR_RELOAD_STATS_ENTRY,	/* nested */
+	DEVLINK_ATTR_RELOAD_STATS_LIMIT,	/* u8 */
+	DEVLINK_ATTR_RELOAD_STATS_VALUE,	/* u32 */
+
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 28b63faa3c6b..a167c3bb468c 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -517,10 +517,66 @@ devlink_reload_limit_is_supported(struct devlink *devlink, enum devlink_reload_l
 	return test_bit(limit, &devlink->ops->reload_limits);
 }
 
+static int devlink_reload_stat_put(struct sk_buff *msg, enum devlink_reload_action action,
+				   enum devlink_reload_limit limit, u32 value)
+{
+	struct nlattr *reload_stats_entry;
+
+	reload_stats_entry = nla_nest_start(msg, DEVLINK_ATTR_RELOAD_STATS_ENTRY);
+	if (!reload_stats_entry)
+		return -EMSGSIZE;
+
+	if (nla_put_u8(msg, DEVLINK_ATTR_RELOAD_ACTION, action) ||
+	    nla_put_u8(msg, DEVLINK_ATTR_RELOAD_STATS_LIMIT, limit) ||
+	    nla_put_u32(msg, DEVLINK_ATTR_RELOAD_STATS_VALUE, value))
+		goto nla_put_failure;
+	nla_nest_end(msg, reload_stats_entry);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, reload_stats_entry);
+	return -EMSGSIZE;
+}
+
+static int devlink_reload_stats_put(struct sk_buff *msg, struct devlink *devlink)
+{
+	struct nlattr *reload_stats_attr;
+	int i, j, stat_idx;
+	u32 value;
+
+	reload_stats_attr = nla_nest_start(msg, DEVLINK_ATTR_RELOAD_STATS);
+
+	if (!reload_stats_attr)
+		return -EMSGSIZE;
+
+	for (j = 0; j <= DEVLINK_RELOAD_LIMIT_MAX; j++) {
+		if (j != DEVLINK_RELOAD_LIMIT_UNSPEC &&
+		    !devlink_reload_limit_is_supported(devlink, j))
+			continue;
+		for (i = 0; i <= DEVLINK_RELOAD_ACTION_MAX; i++) {
+			if (!devlink_reload_action_is_supported(devlink, i) ||
+			    devlink_reload_combination_is_invalid(i, j))
+				continue;
+
+			stat_idx = j * __DEVLINK_RELOAD_ACTION_MAX + i;
+			value = devlink->stats.reload_stats[stat_idx];
+			if (devlink_reload_stat_put(msg, i, j, value))
+				goto nla_put_failure;
+		}
+	}
+	nla_nest_end(msg, reload_stats_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, reload_stats_attr);
+	return -EMSGSIZE;
+}
+
 static int devlink_nl_fill(struct sk_buff *msg, struct devlink *devlink,
 			   enum devlink_command cmd, u32 portid,
 			   u32 seq, int flags)
 {
+	struct nlattr *dev_stats;
 	void *hdr;
 
 	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
@@ -532,9 +588,19 @@ static int devlink_nl_fill(struct sk_buff *msg, struct devlink *devlink,
 	if (nla_put_u8(msg, DEVLINK_ATTR_RELOAD_FAILED, devlink->reload_failed))
 		goto nla_put_failure;
 
+	dev_stats = nla_nest_start(msg, DEVLINK_ATTR_DEV_STATS);
+	if (!dev_stats)
+		goto nla_put_failure;
+
+	if (devlink_reload_stats_put(msg, devlink))
+		goto dev_stats_nest_cancel;
+
+	nla_nest_end(msg, dev_stats);
 	genlmsg_end(msg, hdr);
 	return 0;
 
+dev_stats_nest_cancel:
+	nla_nest_cancel(msg, dev_stats);
 nla_put_failure:
 	genlmsg_cancel(msg, hdr);
 	return -EMSGSIZE;
@@ -3021,6 +3087,29 @@ bool devlink_is_reload_failed(const struct devlink *devlink)
 }
 EXPORT_SYMBOL_GPL(devlink_is_reload_failed);
 
+static void
+__devlink_reload_stats_update(struct devlink *devlink, u32 *reload_stats,
+			      enum devlink_reload_limit limit, u32 actions_performed)
+{
+	unsigned long actions = actions_performed;
+	int stat_idx;
+	int action;
+
+	for_each_set_bit(action, &actions, __DEVLINK_RELOAD_ACTION_MAX) {
+		stat_idx = limit * __DEVLINK_RELOAD_ACTION_MAX + action;
+		reload_stats[stat_idx]++;
+	}
+	devlink_notify(devlink, DEVLINK_CMD_NEW);
+}
+
+static void
+devlink_reload_stats_update(struct devlink *devlink, enum devlink_reload_limit limit,
+			    u32 actions_performed)
+{
+	__devlink_reload_stats_update(devlink, devlink->stats.reload_stats, limit,
+				      actions_performed);
+}
+
 static int devlink_reload(struct devlink *devlink, struct net *dest_net,
 			  enum devlink_reload_action action, enum devlink_reload_limit limit,
 			  u32 *actions_performed, struct netlink_ext_ack *extack)
@@ -3043,6 +3132,7 @@ static int devlink_reload(struct devlink *devlink, struct net *dest_net,
 		return err;
 
 	WARN_ON(!(*actions_performed & BIT(action)));
+	devlink_reload_stats_update(devlink, limit, *actions_performed);
 	return 0;
 }
 
-- 
2.18.2