Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752637AbdLSTtB (ORCPT ); Tue, 19 Dec 2017 14:49:01 -0500 Received: from mga01.intel.com ([192.55.52.88]:17651 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753033AbdLSTgi (ORCPT ); Tue, 19 Dec 2017 14:36:38 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,428,1508828400"; d="scan'208";a="4018536" From: Dongwon Kim To: linux-kernel@vger.kernel.org Cc: dri-devel@lists.freedesktop.org, xen-devel@lists.xenproject.org, mateuszx.potrola@intel.com, dongwon.kim@intel.com Subject: [RFC PATCH 18/60] hyper_dmabuf: reset comm channel when one end has disconnected. Date: Tue, 19 Dec 2017 11:29:34 -0800 Message-Id: <1513711816-2618-18-git-send-email-dongwon.kim@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1513711816-2618-1-git-send-email-dongwon.kim@intel.com> References: <1513711816-2618-1-git-send-email-dongwon.kim@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2861 Lines: 87 From: Mateusz Polrola When exporter or importer is disconnected, ring buffer should be reinitialzed, otherwise on next reconnection exporter/importer will receive old requests/responses remaining in the ring buffer, which are not valid anymore. This patch also blocks back ring irq until communication channel is initialized and fully active to prevent a race condition. Signed-off-by: Dongwon Kim --- .../xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c | 24 +++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c b/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c index 5e7a250..b629032 100644 --- a/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c +++ b/drivers/xen/hyper_dmabuf/xen/hyper_dmabuf_xen_comm.c @@ -282,6 +282,7 @@ int hyper_dmabuf_xen_init_tx_rbuf(int domid) void hyper_dmabuf_xen_cleanup_tx_rbuf(int domid) { struct xen_comm_tx_ring_info *ring_info; + struct xen_comm_rx_ring_info *rx_ring_info; /* check if we at all have exporter ring for given rdomain */ ring_info = xen_comm_find_tx_ring(domid); @@ -307,6 +308,12 @@ void hyper_dmabuf_xen_cleanup_tx_rbuf(int domid) (unsigned long) ring_info->ring_front.sring); kfree(ring_info); + + rx_ring_info = xen_comm_find_rx_ring(domid); + if (!rx_ring_info) + return; + + BACK_RING_INIT(&(rx_ring_info->ring_back), rx_ring_info->ring_back.sring, PAGE_SIZE); } /* importer needs to know about shared page and port numbers for @@ -378,9 +385,8 @@ int hyper_dmabuf_xen_init_rx_rbuf(int domid) BACK_RING_INIT(&ring_info->ring_back, sring, PAGE_SIZE); - ret = bind_interdomain_evtchn_to_irqhandler(domid, rx_port, - back_ring_isr, 0, - NULL, (void*)ring_info); + ret = bind_interdomain_evtchn_to_irq(domid, rx_port); + if (ret < 0) { return -EINVAL; } @@ -399,6 +405,10 @@ int hyper_dmabuf_xen_init_rx_rbuf(int domid) ret = hyper_dmabuf_xen_init_tx_rbuf(domid); } + ret = request_irq(ring_info->irq, + back_ring_isr, 0, + NULL, (void*)ring_info); + return ret; } @@ -406,6 +416,7 @@ int hyper_dmabuf_xen_init_rx_rbuf(int domid) void hyper_dmabuf_xen_cleanup_rx_rbuf(int domid) { struct xen_comm_rx_ring_info *ring_info; + struct xen_comm_tx_ring_info *tx_ring_info; struct page *shared_ring; /* check if we have importer ring created for given sdomain */ @@ -425,6 +436,13 @@ void hyper_dmabuf_xen_cleanup_rx_rbuf(int domid) gnttab_free_pages(1, &shared_ring); kfree(ring_info); + + tx_ring_info = xen_comm_find_tx_ring(domid); + if (!tx_ring_info) + return; + + SHARED_RING_INIT(tx_ring_info->ring_front.sring); + FRONT_RING_INIT(&(tx_ring_info->ring_front), tx_ring_info->ring_front.sring, PAGE_SIZE); } int hyper_dmabuf_xen_init_comm_env(void) -- 2.7.4