drm/nouveau: add lockdep annotations

commit 5f97ab913cf0fbc378ea8ffc3ee66f4890d11c55 upstream.

1) Lockdep thinks all nouveau subdevs belong to the same class and can be
locked in arbitrary order, which is not true (at least in general case).
Tell it to distinguish subdevs by (o)class type.
2) DRM client can be locked under user client lock - tell lockdep to put
DRM client lock in a separate class.

Reported-by: Arend van Spriel <arend@broadcom.com>
Reported-by: Peter Hurley <peter@hurleysoftware.com>
Reported-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reported-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/nouveau/core/core/subdev.c b/drivers/gpu/drm/nouveau/core/core/subdev.c
index f74c30aa33a0e334eda733ae1a0ea5b9a3d10377..48f06378d3f9d5f9e09e03291a11d6e26527f674 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/core/subdev.c
+++ b/drivers/gpu/drm/nouveau/core/core/subdev.c
@@ -99,7 +99,7 @@ nouveau_subdev_create_(struct nouveau_object *parent,
        if (ret)
                return ret;
 
-       mutex_init(&subdev->mutex);
+       __mutex_init(&subdev->mutex, subname, &oclass->lock_class_key);
        subdev->name = subname;
 
        if (parent) {

diff --git a/drivers/gpu/drm/nouveau/core/include/core/object.h b/drivers/gpu/drm/nouveau/core/include/core/object.h
index 486f1a9217fd6cd51dc2c5530d455eaa155c86b4..727ba4f87bf16f6d3673a4e3e141c308533cc8e2 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/include/core/object.h
+++ b/drivers/gpu/drm/nouveau/core/include/core/object.h
@@ -50,10 +50,13 @@ int  nouveau_object_fini(struct nouveau_object *, bool suspend);
 
 extern struct nouveau_ofuncs nouveau_object_ofuncs;
 
+/* Don't allocate dynamically, because lockdep needs lock_class_keys to be in
+ * ".data". */
 struct nouveau_oclass {
        u32 handle;
-       struct nouveau_ofuncs *ofuncs;
-       struct nouveau_omthds *omthds;
+       struct nouveau_ofuncs * ofuncs;
+       struct nouveau_omthds * const omthds;
+       struct lock_class_key lock_class_key;
 };
 
 #define nv_oclass(o)    nv_object(o)->oclass

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 8503b2ea570a0616234e409c524593f37a98648e..572c216afe548ec065298a6645750558eeb410fb 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -241,6 +241,8 @@ nouveau_drm_probe(struct pci_dev *pdev, const struct pci_device_id *pent)
        return 0;
 }
 
+static struct lock_class_key drm_client_lock_class_key;
+
 static int
 nouveau_drm_load(struct drm_device *dev, unsigned long flags)
 {
@@ -252,6 +254,7 @@ nouveau_drm_load(struct drm_device *dev, unsigned long flags)
        ret = nouveau_cli_create(pdev, "DRM", sizeof(*drm), (void**)&drm);
        if (ret)
                return ret;
+       lockdep_set_class(&drm->client.mutex, &drm_client_lock_class_key);
 
        dev->dev_private = drm;
        drm->dev = dev;