Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754500AbbGaTwr (ORCPT ); Fri, 31 Jul 2015 15:52:47 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46397 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754305AbbGaTwm (ORCPT ); Fri, 31 Jul 2015 15:52:42 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Vetter , Daniel Vetter , Dave Airlie Subject: [PATCH 4.1 132/267] drm/dp/mst: make sure mst_primary mstb is valid in work function Date: Fri, 31 Jul 2015 12:39:43 -0700 Message-Id: <20150731194006.096703619@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150731194001.933895871@linuxfoundation.org> References: <20150731194001.933895871@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2375 Lines: 75 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Vetter commit 9254ec496a1dbdddeab50021a8138dc627a8166a upstream. This validates the mst_primary under the lock, and then calls into the check and send function. This makes the code a lot easier to understand the locking rules in. Signed-off-by: Daniel Vetter Reviewed-by: Daniel Vetter Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_dp_mst_topology.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -1200,7 +1200,7 @@ static void drm_dp_check_and_send_link_a struct drm_dp_mst_branch *mstb) { struct drm_dp_mst_port *port; - + struct drm_dp_mst_branch *mstb_child; if (!mstb->link_address_sent) { drm_dp_send_link_address(mgr, mstb); mstb->link_address_sent = true; @@ -1215,17 +1215,31 @@ static void drm_dp_check_and_send_link_a if (!port->available_pbn) drm_dp_send_enum_path_resources(mgr, mstb, port); - if (port->mstb) - drm_dp_check_and_send_link_address(mgr, port->mstb); + if (port->mstb) { + mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb); + if (mstb_child) { + drm_dp_check_and_send_link_address(mgr, mstb_child); + drm_dp_put_mst_branch_device(mstb_child); + } + } } } static void drm_dp_mst_link_probe_work(struct work_struct *work) { struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work); + struct drm_dp_mst_branch *mstb; - drm_dp_check_and_send_link_address(mgr, mgr->mst_primary); - + mutex_lock(&mgr->lock); + mstb = mgr->mst_primary; + if (mstb) { + kref_get(&mstb->kref); + } + mutex_unlock(&mgr->lock); + if (mstb) { + drm_dp_check_and_send_link_address(mgr, mstb); + drm_dp_put_mst_branch_device(mstb); + } } static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/