drm: Move master pointer from drm_minor to drm_device
There can only be one current master, and it's for the overall device.
Render/control minors don't support master-based auth at all.
This simplifies the master logic a lot, at least in my eyes: All these
additional pointer chases are just confusing.
While doing the conversion I spotted some locking fail:
- drm_lock/drm_auth check dev->master without holding the
master_mutex. This is fallout from
commit c996fd0b956450563454e7ccc97a82ca31f9d043
Author: Thomas Hellstrom <thellstrom@vmware.com>
Date: Tue Feb 25 19:57:44 2014 +0100
drm: Protect the master management with a drm_device::master_mutex v3
but I honestly don't care one bit about those old legacy drivers
using this.
- debugfs name info should just grab master_mutex.
- And the fbdev helper looked at it to figure out whether someone is
using KMS. We just need a consistent value, so READ_ONCE. Aside: We
should probably check if anyone has opened a control node too, but I
guess current userspace doesn't really do that yet.
v2: Balance locking, reported by Julia.
v3: Rebase on top of Chris' oops fixes.
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v2)
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> (v2)
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466499262-18717-1-git-send-email-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index d858e69..6bba6b9 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -128,13 +128,13 @@
lockdep_assert_held_once(&dev->master_mutex);
/* create a new master */
- fpriv->minor->master = drm_master_create(fpriv->minor->dev);
- if (!fpriv->minor->master)
+ dev->master = drm_master_create(dev);
+ if (!dev->master)
return -ENOMEM;
/* take another reference for the copy in the local file priv */
old_master = fpriv->master;
- fpriv->master = drm_master_get(fpriv->minor->master);
+ fpriv->master = drm_master_get(dev->master);
if (dev->driver->master_create) {
ret = dev->driver->master_create(dev, fpriv->master);
@@ -157,7 +157,7 @@
out_err:
/* drop both references and restore old master on failure */
- drm_master_put(&fpriv->minor->master);
+ drm_master_put(&dev->master);
drm_master_put(&fpriv->master);
fpriv->master = old_master;
@@ -173,7 +173,7 @@
if (file_priv->is_master)
goto out_unlock;
- if (file_priv->minor->master) {
+ if (dev->master) {
ret = -EINVAL;
goto out_unlock;
}
@@ -188,13 +188,13 @@
goto out_unlock;
}
- file_priv->minor->master = drm_master_get(file_priv->master);
+ dev->master = drm_master_get(file_priv->master);
file_priv->is_master = 1;
if (dev->driver->master_set) {
ret = dev->driver->master_set(dev, file_priv, false);
if (unlikely(ret != 0)) {
file_priv->is_master = 0;
- drm_master_put(&file_priv->minor->master);
+ drm_master_put(&dev->master);
}
}
@@ -212,13 +212,13 @@
if (!file_priv->is_master)
goto out_unlock;
- if (!file_priv->minor->master)
+ if (!dev->master)
goto out_unlock;
ret = 0;
if (dev->driver->master_drop)
dev->driver->master_drop(dev, file_priv, false);
- drm_master_put(&file_priv->minor->master);
+ drm_master_put(&dev->master);
file_priv->is_master = 0;
out_unlock:
@@ -234,10 +234,10 @@
/* if there is no current master make this fd it, but do not create
* any master object for render clients */
mutex_lock(&dev->master_mutex);
- if (!file_priv->minor->master)
+ if (!dev->master)
ret = drm_new_set_master(dev, file_priv);
else
- file_priv->master = drm_master_get(file_priv->minor->master);
+ file_priv->master = drm_master_get(dev->master);
mutex_unlock(&dev->master_mutex);
return ret;
@@ -271,11 +271,11 @@
mutex_unlock(&dev->struct_mutex);
}
- if (file_priv->minor->master == file_priv->master) {
+ if (dev->master == file_priv->master) {
/* drop the reference held my the minor */
if (dev->driver->master_drop)
dev->driver->master_drop(dev, file_priv, true);
- drm_master_put(&file_priv->minor->master);
+ drm_master_put(&dev->master);
}
out:
/* drop the master reference held by the file priv */