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/include/drm/drmP.h b/include/drm/drmP.h
index 084fd14..3d9a782 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -336,7 +336,7 @@
void *driver_priv;
struct drm_master *master; /* master this node is currently associated with
- N.B. not always minor->master */
+ N.B. not always dev->master */
/**
* fbs - List of framebuffers associated with this file.
*
@@ -708,9 +708,6 @@
struct list_head debugfs_list;
struct mutex debugfs_lock; /* Protects debugfs_list. */
-
- /* currently active master for this node. Protected by master_mutex */
- struct drm_master *master;
};
@@ -759,6 +756,10 @@
struct drm_minor *control; /**< Control node */
struct drm_minor *primary; /**< Primary node */
struct drm_minor *render; /**< Render node */
+
+ /* currently active master for this device. Protected by master_mutex */
+ struct drm_master *master;
+
atomic_t unplugged; /**< Flag whether dev is dead */
struct inode *anon_inode; /**< inode for private address-space */
char *unique; /**< unique name of the device */