From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0ABCCFF8855 for ; Tue, 5 May 2026 20:45:40 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 2316640A4B; Tue, 5 May 2026 22:45:27 +0200 (CEST) Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by mails.dpdk.org (Postfix) with ESMTP id D730A40684; Tue, 5 May 2026 22:45:25 +0200 (CEST) Received: by linux.microsoft.com (Postfix, from userid 1202) id 336E320B7168; Tue, 5 May 2026 13:45:23 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 336E320B7168 From: Long Li To: dev@dpdk.org, Wei Hu , Stephen Hemminger Cc: Long Li , stable@dpdk.org Subject: [PATCH 5/7] net/netvsc: retry when no matching MAC found in net directory Date: Tue, 5 May 2026 13:44:54 -0700 Message-ID: <20260505204457.267934-5-longli@microsoft.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20260505204457.267934-1-longli@microsoft.com> References: <20260505204457.267934-1-longli@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On multi-NIC Azure VMs, a single MANA PCI device (7870:00:00.0) hosts multiple VF interfaces. After PCI rescan, these interfaces register at different times — the management NIC's VF appears first, followed by the test NIC's VF. Previously, when netvsc_hotplug_retry scanned the net/ directory and found interfaces with non-matching MACs, it would exit the readdir loop and free the hotadd context, permanently giving up. The matching VF interface had not appeared yet. Now, when the readdir loop ends without finding a matching MAC (dir is NULL after loop), schedule another retry instead of giving up. This uses a separate mac_retry counter (limit 30, ~30 seconds) so the main retry loop remains unlimited. Fixes: a2a23a794b3a ("net/netvsc: support VF device hot add/remove") Cc: stable@dpdk.org Signed-off-by: Long Li --- drivers/net/netvsc/hn_ethdev.c | 34 ++++++++++++++++++++++++++++++++++ drivers/net/netvsc/hn_var.h | 1 + 2 files changed, 35 insertions(+) diff --git a/drivers/net/netvsc/hn_ethdev.c b/drivers/net/netvsc/hn_ethdev.c index 124af4f1a1..8d9d6bbe8b 100644 --- a/drivers/net/netvsc/hn_ethdev.c +++ b/drivers/net/netvsc/hn_ethdev.c @@ -92,6 +92,12 @@ struct netvsc_mp_param { /* Retry interval for hot-add VF device (microseconds) */ #define NETVSC_HOTADD_RETRY_INTERVAL 1000000 +/* Max retries when net/ directory exists but no matching MAC found. + * On multi-NIC PCI devices, a second VF may register later. + * 120 retries = ~2 minutes. + */ +#define NETVSC_MAX_MAC_RETRY 120 + struct hn_xstats_name_off { char name[RTE_ETH_XSTATS_NAME_SIZE]; unsigned int offset; @@ -763,6 +769,34 @@ static void netvsc_hotplug_retry(void *args) } } + /* If we opened the net directory but didn't find a matching MAC, + * the VF interface may not have appeared yet (e.g. on a multi-NIC + * PCI device, the second VF registers later). Retry. + */ + if (di) { + closedir(di); + di = NULL; + if (!dir) { + /* readdir returned NULL — loop ended without match */ + hot_ctx->mac_retry++; + if (hot_ctx->mac_retry < NETVSC_MAX_MAC_RETRY) { + PMD_DRV_LOG(NOTICE, + "%s: no matching MAC found in %s, " + "retrying in 1 second (mac_retry %d/%d)", + __func__, buf, + hot_ctx->mac_retry, + NETVSC_MAX_MAC_RETRY); + rte_eal_alarm_set(NETVSC_HOTADD_RETRY_INTERVAL, + netvsc_hotplug_retry, + hot_ctx); + return; + } + PMD_DRV_LOG(NOTICE, + "%s: no matching MAC found after %d retries, giving up", + __func__, hot_ctx->mac_retry); + } + } + free_hotadd_ctx: if (di) closedir(di); diff --git a/drivers/net/netvsc/hn_var.h b/drivers/net/netvsc/hn_var.h index ef55dee28e..574b909c82 100644 --- a/drivers/net/netvsc/hn_var.h +++ b/drivers/net/netvsc/hn_var.h @@ -127,6 +127,7 @@ struct hv_hotadd_context { struct hn_data *hv; struct rte_devargs da; int eal_hot_plug_retry; + int mac_retry; }; struct hn_data { -- 2.43.0