mana_query_link_cfg() sends an HWC command to firmware on every call, but the link speed and QoS values it returns only change when the driver explicitly calls mana_set_bw_clamp(). This function is called not only by userspace via ethtool get_link_ksettings, but also periodically by hv_netvsc through netvsc_get_link_ksettings and by the sysfs speed_show attribute via dev_attr_show, resulting in unnecessary HWC traffic every few minutes.
Add a link_cfg_error field to mana_port_context to cache the query result. The field uses three states: 1 (not yet queried, initial value set during mana_probe_port), 0 (success, speed/max_speed are valid), or a negative errno for permanent errors like -EOPNOTSUPP when the hardware does not support the command. Transient errors and qos_unconfigured responses are not cached so that subsequent calls will retry. To prevent a concurrent mana_set_bw_clamp() from racing with an in-flight query and publishing stale pre-clamp speed/max_speed, serialize the firmware transaction and the cache update under a new per-port mutex (link_cfg_mutex). The mutex covers both the HWC request and the subsequent stores in mana_query_link_cfg(), and the HWC request and invalidation in mana_set_bw_clamp(). With this lock held, two queries can no longer interleave their speed/max_speed stores, and an invalidation can no longer slip in between a query's response and its publish. Invalidate the cache inside mana_set_bw_clamp() on success, so all current and future callers that change the link configuration automatically trigger a fresh query on the next mana_query_link_cfg() call. Also reset link_cfg_error during resume in mana_probe() under link_cfg_mutex, so that any slow-path query already in flight cannot later store 0 and silently overwrite the post-resume invalidation. Signed-off-by: Erni Sri Satya Vennela <[email protected]> Reviewed-by: Haiyang Zhang <[email protected]> --- drivers/net/ethernet/microsoft/mana/mana_en.c | 41 +++++++++++++++---- include/net/mana/mana.h | 4 ++ 2 files changed, 36 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c index 82f1461a48e9..43018bc13dc1 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -1456,6 +1456,12 @@ int mana_query_link_cfg(struct mana_port_context *apc) struct mana_query_link_config_req req = {}; int err; + mutex_lock(&apc->link_cfg_mutex); + + err = apc->link_cfg_error; + if (err <= 0) + goto out; + mana_gd_init_req_hdr(&req.hdr, MANA_QUERY_LINK_CONFIG, sizeof(req), sizeof(resp)); @@ -1468,10 +1474,11 @@ int mana_query_link_cfg(struct mana_port_context *apc) if (err) { if (err == -EOPNOTSUPP) { netdev_info_once(ndev, "MANA_QUERY_LINK_CONFIG not supported\n"); - return err; + apc->link_cfg_error = err; + goto out; } netdev_err(ndev, "Failed to query link config: %d\n", err); - return err; + goto out; } err = mana_verify_resp_hdr(&resp.hdr, MANA_QUERY_LINK_CONFIG, @@ -1482,16 +1489,20 @@ int mana_query_link_cfg(struct mana_port_context *apc) resp.hdr.status); if (!err) err = -EOPNOTSUPP; - return err; + goto out; } if (resp.qos_unconfigured) { err = -EINVAL; - return err; + goto out; } apc->speed = resp.link_speed_mbps; apc->max_speed = resp.qos_speed_mbps; - return 0; + apc->link_cfg_error = 0; + err = 0; +out: + mutex_unlock(&apc->link_cfg_mutex); + return err; } int mana_set_bw_clamp(struct mana_port_context *apc, u32 speed, @@ -1508,17 +1519,19 @@ int mana_set_bw_clamp(struct mana_port_context *apc, u32 speed, req.link_speed_mbps = speed; req.enable_clamping = enable_clamping; + mutex_lock(&apc->link_cfg_mutex); + err = mana_send_request(apc->ac, &req, sizeof(req), &resp, sizeof(resp)); if (err) { if (err == -EOPNOTSUPP) { netdev_info_once(ndev, "MANA_SET_BW_CLAMP not supported\n"); - return err; + goto out; } netdev_err(ndev, "Failed to set bandwidth clamp for speed %u, err = %d", speed, err); - return err; + goto out; } err = mana_verify_resp_hdr(&resp.hdr, MANA_SET_BW_CLAMP, @@ -1529,13 +1542,18 @@ int mana_set_bw_clamp(struct mana_port_context *apc, u32 speed, resp.hdr.status); if (!err) err = -EOPNOTSUPP; - return err; + goto out; } if (resp.qos_unconfigured) netdev_info(ndev, "QoS is unconfigured\n"); - return 0; + /* Invalidate the cache; next query will re-fetch from firmware. */ + apc->link_cfg_error = 1; + err = 0; +out: + mutex_unlock(&apc->link_cfg_mutex); + return err; } int mana_create_wq_obj(struct mana_port_context *apc, @@ -3430,6 +3448,8 @@ static int mana_probe_port(struct mana_context *ac, int port_idx, apc->port_handle = INVALID_MANA_HANDLE; apc->pf_filter_handle = INVALID_MANA_HANDLE; apc->port_idx = port_idx; + apc->link_cfg_error = 1; + mutex_init(&apc->link_cfg_mutex); apc->cqe_coalescing_enable = 0; mutex_init(&apc->vport_mutex); @@ -3750,6 +3770,9 @@ int mana_probe(struct gdma_dev *gd, bool resuming) rtnl_lock(); apc = netdev_priv(ac->ports[i]); enable_work(&apc->queue_reset_work); + mutex_lock(&apc->link_cfg_mutex); + apc->link_cfg_error = 1; + mutex_unlock(&apc->link_cfg_mutex); err = mana_attach(ac->ports[i]); rtnl_unlock(); /* Log the port for which the attach failed, stop diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h index d9c27310fd04..af772b7297ec 100644 --- a/include/net/mana/mana.h +++ b/include/net/mana/mana.h @@ -555,6 +555,10 @@ struct mana_port_context { u32 speed; /* Maximum speed supported by the SKU (mbps) */ u32 max_speed; + /* 1 = not queried, 0 = cached success, negative = permanent error */ + int link_cfg_error; + /* Serializes mana_query_link_cfg() and mana_set_bw_clamp(). */ + struct mutex link_cfg_mutex; bool port_is_up; bool port_st_save; /* Saved port state */ -- 2.34.1
