[PATCH 4.6 085/121] drm/vmwgfx: Kill some lockdep warnings

Greg Kroah-Hartman
2016-06-05T21:58:16Z

From: Thomas Hellstrom <thellstrom@vmware.com>

commit 93cd16817ae5ddcfc548784b51c76bf6d7923442 upstream.

Some global KMS state that is elsewhere protected by the mode_config
mutex here needs to be protected with a local mutex. Remove corresponding
lockdep checks and introduce a new driver-private global_kms_state_mutex,
and make sure its locking order is *after* the crtc locks in order to
avoid having to release those when the new mutex is taken.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 1 +
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 1 +
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 27 +++++++++++++--------------
drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c | 3 +++
drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c | 3 +++
5 files changed, 21 insertions(+), 14 deletions(-)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -628,6 +628,7 @@ static int vmw_driver_load(struct drm_de
mutex_init(&dev_priv->cmdbuf_mutex);
mutex_init(&dev_priv->release_mutex);
mutex_init(&dev_priv->binding_mutex);
+ mutex_init(&dev_priv->global_kms_state_mutex);
rwlock_init(&dev_priv->resource_lock);
ttm_lock_init(&dev_priv->reservation_sem);
spin_lock_init(&dev_priv->hw_lock);
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -412,6 +412,7 @@ struct vmw_private {
struct drm_property *implicit_placement_property;
unsigned num_implicit;
struct vmw_framebuffer *implicit_fb;
+ struct mutex global_kms_state_mutex;

/*
* Context and surface management.
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -2143,13 +2143,13 @@ int vmw_kms_fbdev_init_data(struct vmw_p
void vmw_kms_del_active(struct vmw_private *dev_priv,
struct vmw_display_unit *du)
{
- lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
-
+ mutex_lock(&dev_priv->global_kms_state_mutex);
if (du->active_implicit) {
if (--(dev_priv->num_implicit) == 0)
dev_priv->implicit_fb = NULL;
du->active_implicit = false;
}
+ mutex_unlock(&dev_priv->global_kms_state_mutex);
}

/**
@@ -2165,8 +2165,7 @@ void vmw_kms_add_active(struct vmw_priva
struct vmw_display_unit *du,
struct vmw_framebuffer *vfb)
{
- lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
-
+ mutex_lock(&dev_priv->global_kms_state_mutex);
WARN_ON_ONCE(!dev_priv->num_implicit && dev_priv->implicit_fb);

if (!du->active_implicit && du->is_implicit) {
@@ -2174,6 +2173,7 @@ void vmw_kms_add_active(struct vmw_priva
du->active_implicit = true;
dev_priv->num_implicit++;
}
+ mutex_unlock(&dev_priv->global_kms_state_mutex);
}

/**
@@ -2190,16 +2190,13 @@ bool vmw_kms_crtc_flippable(struct vmw_p
struct drm_crtc *crtc)
{
struct vmw_display_unit *du = vmw_crtc_to_du(crtc);
+ bool ret;

- lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
-
- if (!du->is_implicit)
- return true;
-
- if (dev_priv->num_implicit != 1)
- return false;
+ mutex_lock(&dev_priv->global_kms_state_mutex);
+ ret = !du->is_implicit || dev_priv->num_implicit == 1;
+ mutex_unlock(&dev_priv->global_kms_state_mutex);

- return true;
+ return ret;
}

/**
@@ -2214,16 +2211,18 @@ void vmw_kms_update_implicit_fb(struct v
struct vmw_display_unit *du = vmw_crtc_to_du(crtc);
struct vmw_framebuffer *vfb;

- lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
+ mutex_lock(&dev_priv->global_kms_state_mutex);

if (!du->is_implicit)
- return;
+ goto out_unlock;

vfb = vmw_framebuffer_to_vfb(crtc->primary->fb);
WARN_ON_ONCE(dev_priv->num_implicit != 1 &&
dev_priv->implicit_fb != vfb);

dev_priv->implicit_fb = vfb;
+out_unlock:
+ mutex_unlock(&dev_priv->global_kms_state_mutex);
}

/**
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
@@ -285,14 +285,17 @@ static int vmw_sou_crtc_set_config(struc
}

/* Only one active implicit frame-buffer at a time. */
+ mutex_lock(&dev_priv->global_kms_state_mutex);
if (sou->base.is_implicit &&
dev_priv->implicit_fb && vfb &&
!(dev_priv->num_implicit == 1 &&
sou->base.active_implicit) &&
dev_priv->implicit_fb != vfb) {
+ mutex_unlock(&dev_priv->global_kms_state_mutex);
DRM_ERROR("Multiple implicit framebuffers not supported.\n");
return -EINVAL;
}
+ mutex_unlock(&dev_priv->global_kms_state_mutex);

/* since they always map one to one these are safe */
connector = &sou->base.connector;
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -553,12 +553,15 @@ static int vmw_stdu_crtc_set_config(stru
}

/* Only one active implicit frame-buffer at a time. */
+ mutex_lock(&dev_priv->global_kms_state_mutex);
if (!turning_off && stdu->base.is_implicit && dev_priv->implicit_fb &&
!(dev_priv->num_implicit == 1 && stdu->base.active_implicit)
&& dev_priv->implicit_fb != vfb) {
+ mutex_unlock(&dev_priv->global_kms_state_mutex);
DRM_ERROR("Multiple implicit framebuffers not supported.\n");
return -EINVAL;
}
+ mutex_unlock(&dev_priv->global_kms_state_mutex);

/* Since they always map one to one these are safe */
connector = &stdu->base.connector;