From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755079AbcE3OSJ (ORCPT ); Mon, 30 May 2016 10:18:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53953 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933060AbcE3OSH (ORCPT ); Mon, 30 May 2016 10:18:07 -0400 From: Vitaly Kuznetsov To: linux-pci@vger.kernel.org Cc: linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, Bjorn Helgaas , Haiyang Zhang , "K. Y. Srinivasan" , Jake Oshins Subject: [PATCH 2/2] PCI: hv: handle all pending messages in hv_pci_onchannelcallback() Date: Mon, 30 May 2016 16:17:59 +0200 Message-Id: <1464617879-19581-3-git-send-email-vkuznets@redhat.com> In-Reply-To: <1464617879-19581-1-git-send-email-vkuznets@redhat.com> References: <1464617879-19581-1-git-send-email-vkuznets@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 30 May 2016 14:18:06 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we have an interrupt from host we have a bit set in event page indicating there are messages for the particular channel. We need to read them all as we won't get signaled for what was on the queue before we cleared the bit in vmbus_on_event(). This applies to all Hyper-V drivers and the pass-through driver should do the same. I did non meet any bugs, the issue was found by code inspection. We don't have many events going through hv_pci_onchannelcallback(), this explains why nobody reported the issue before. While on it, fix handling non-zero vmbus_recvpacket_raw() return values by dropping out. If the return value is not zero it is wrong to inspect buffer or bytes_recvd as these may contain invalid data. Signed-off-by: Vitaly Kuznetsov --- drivers/pci/host/pci-hyperv.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index a68ec49..7de341d 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1657,12 +1657,16 @@ static void hv_pci_onchannelcallback(void *context) continue; } + /* Zero length indicates there are no more packets. */ + if (ret || !bytes_recvd) + break; + /* * All incoming packets must be at least as large as a * response. */ if (bytes_recvd <= sizeof(struct pci_response)) - break; + continue; desc = (struct vmpacket_descriptor *)buffer; switch (desc->type) { @@ -1724,7 +1728,6 @@ static void hv_pci_onchannelcallback(void *context) desc->type, req_id, bytes_recvd); break; } - break; } kfree(buffer); -- 2.5.5