From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [PATCH] bus/vmbus: fix race in sub channel creation Date: Fri, 30 Nov 2018 12:24:57 -0800 Message-ID: <20181130202457.10888-1-stephen@networkplumber.org> References: <1543575881.5400.33.camel@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: mgamal@redhat.com, Stephen Hemminger , Stephen Hemminger To: dev@dpdk.org Return-path: Received: from mail-pl1-f194.google.com (mail-pl1-f194.google.com [209.85.214.194]) by dpdk.org (Postfix) with ESMTP id 1F6EE29CB for ; Fri, 30 Nov 2018 21:25:02 +0100 (CET) Received: by mail-pl1-f194.google.com with SMTP id b5so3337581plr.4 for ; Fri, 30 Nov 2018 12:25:01 -0800 (PST) In-Reply-To: <1543575881.5400.33.camel@redhat.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" When using multiple queues, there was a race with the kernel in setting up the second channel. This is do due to a kernel change whiche does not allow accessing sysfs files for Hyper-V channels that are not opened. The fix is simple, just move the logic to detect not ready sub channels earlier in the existing loop. Fixes: 831dba47bd36 ("bus/vmbus: add Hyper-V virtual bus support") Reported-by:Mohammed Gamal Signed-off-by: Stephen Hemminger --- drivers/bus/vmbus/linux/vmbus_uio.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/bus/vmbus/linux/vmbus_uio.c b/drivers/bus/vmbus/linux/vmbus_uio.c index 12e97e3a420a..38df4d724ed5 100644 --- a/drivers/bus/vmbus/linux/vmbus_uio.c +++ b/drivers/bus/vmbus/linux/vmbus_uio.c @@ -357,6 +357,12 @@ int vmbus_uio_get_subchan(struct vmbus_channel *primary, continue; } + if (!vmbus_isnew_subchannel(primary, relid)) + continue; /* Already know about you */ + + if (!vmbus_uio_ring_present(dev, relid)) + continue; /* Ring may not be ready yet */ + snprintf(subchan_path, sizeof(subchan_path), "%s/%lu", chan_path, relid); err = vmbus_uio_sysfs_read(subchan_path, "subchannel_id", @@ -370,12 +376,6 @@ int vmbus_uio_get_subchan(struct vmbus_channel *primary, if (subid == 0) continue; /* skip primary channel */ - if (!vmbus_isnew_subchannel(primary, relid)) - continue; - - if (!vmbus_uio_ring_present(dev, relid)) - continue; /* Ring may not be ready yet */ - err = vmbus_uio_sysfs_read(subchan_path, "monitor_id", &monid, UINT8_MAX); if (err) { -- 2.19.2