From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757030AbbA2Nb3 (ORCPT ); Thu, 29 Jan 2015 08:31:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38027 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756177AbbA2NbR (ORCPT ); Thu, 29 Jan 2015 08:31:17 -0500 From: Vitaly Kuznetsov To: Dexuan Cui Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, driverdev-devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, jasowang@redhat.com, kys@microsoft.com, haiyangz@microsoft.com Subject: Re: [PATCH 2/3] hv: vmbus_post_msg: retry the hypercall on HV_STATUS_INVALID_CONNECTION_ID References: <1422529361-28228-1-git-send-email-decui@microsoft.com> Date: Thu, 29 Jan 2015 14:30:57 +0100 In-Reply-To: <1422529361-28228-1-git-send-email-decui@microsoft.com> (Dexuan Cui's message of "Thu, 29 Jan 2015 03:02:41 -0800") Message-ID: <87bnlh7lym.fsf@vitty.brq.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dexuan Cui writes: > I got the hypercall error code on Hyper-V 2008 R2 when keeping running > "rmmod hv_netvsc; modprobe hv_netvsc; rmmod hv_utils; modprobe hv_utils" > in a Linux guest. > > Without the patch, the driver can occasionally fail to load. > > CC: "K. Y. Srinivasan" > Signed-off-by: Dexuan Cui > --- > arch/x86/include/uapi/asm/hyperv.h | 1 + > drivers/hv/connection.c | 9 +++++++++ > 2 files changed, 10 insertions(+) > > diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h > index 90c458e..b9daffb 100644 > --- a/arch/x86/include/uapi/asm/hyperv.h > +++ b/arch/x86/include/uapi/asm/hyperv.h > @@ -225,6 +225,7 @@ > #define HV_STATUS_INVALID_HYPERCALL_CODE 2 > #define HV_STATUS_INVALID_HYPERCALL_INPUT 3 > #define HV_STATUS_INVALID_ALIGNMENT 4 > +#define HV_STATUS_INVALID_CONNECTION_ID 18 > #define HV_STATUS_INSUFFICIENT_BUFFERS 19 The gap beween 4 and 18 tells me there are other codes here ;-) Are they all 'permanent failures'? > > typedef struct _HV_REFERENCE_TSC_PAGE { > diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c > index c4acd1c..8bd05f3 100644 > --- a/drivers/hv/connection.c > +++ b/drivers/hv/connection.c > @@ -440,6 +440,15 @@ int vmbus_post_msg(void *buffer, size_t buflen) > ret = hv_post_message(conn_id, 1, buffer, buflen); > > switch (ret) { > + case HV_STATUS_INVALID_CONNECTION_ID: > + /* > + * We could get this if we send messages too > + * frequently or the host is under low resource > + * conditions: let's wait 1 more second before > + * retrying the hypercall. > + */ > + msleep(1000); > + break; In case it is our last try (No. 10) we will return '18' from the function. I suggest we set ret = -ENOMEM here as well. > case HV_STATUS_INSUFFICIENT_BUFFERS: > ret = -ENOMEM; Or should we treat these two equally? There is a smaller (100ms) sleep between tries already, we can consider changing it instead. > case -ENOMEM: -- Vitaly