drm/nouveau: add lockdep annotations

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>
Cc: stable@vger.kernel.org [3.7, but needs s/const ofuncs/ofuncs/ to build]
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

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 5982935ee23a96896fb12d98e2dc5f723ab245e0..106bb19fdd9a65ee12b0c92241ea5045a4b692ac 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 * const 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 efcfefa04123a55125de5f7889b5c1851324e263..43c78516941b88e42c4e14c2468b2cd84092aa1c 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -245,6 +245,8 @@ 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)
 {
@@ -256,6 +258,7 @@ 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;