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[3.19.y-ckt,stable] Patch "drm/dp/mst: make sure mst_primary mstb is valid in work function" has been added to staging queue

Message ID 1437008480-3633-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa July 16, 2015, 1:01 a.m. UTC 
This is a note to let you know that I have just added a patch titled

    drm/dp/mst: make sure mst_primary mstb is valid in work function

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.y-ckt4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

From 4bec1c3c44a859779e1cd7bc582c7718b983fae0 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Mon, 22 Jun 2015 17:31:59 +1000
Subject: drm/dp/mst: make sure mst_primary mstb is valid in work function

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 <daniel.vetter@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

--
1.9.1
diff mbox

Patch

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 9a5b687..e0da405 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1185,7 +1185,7 @@  static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m
 					       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;
@@ -1200,17 +1200,31 @@  static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m
 		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,