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@xxxxxxxxxx>
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.
Cc: Julia Lawall <julia.lawall@xxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
drivers/gpu/drm/drm_auth.c | 26 +++++++++++++-------------
drivers/gpu/drm/drm_bufs.c | 8 ++++----
drivers/gpu/drm/drm_fb_helper.c | 2 +-
drivers/gpu/drm/drm_info.c | 10 ++++++++--
drivers/gpu/drm/drm_lock.c | 2 +-
drivers/gpu/drm/sis/sis_mm.c | 2 +-
drivers/gpu/drm/via/via_mm.c | 2 +-
include/drm/drmP.h | 9 +++++----
8 files changed, 34 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 94761e4bd1e5..fcadd8e1de28 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -128,13 +128,13 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
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 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
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 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
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 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
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 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
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 @@ int drm_master_open(struct drm_file *file_priv)
/* 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 @@ void drm_master_release(struct drm_file *file_priv)
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);
}
/* drop the master reference held by the file priv */
diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index 9b34158c0f77..c3a12cd8bd0d 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -51,7 +51,7 @@ static struct drm_map_list *drm_find_matching_map(struct drm_device *dev,
*/
if (!entry->map ||
map->type != entry->map->type ||
- entry->master != dev->primary->master)
+ entry->master != dev->master)
continue;
switch (map->type) {
case _DRM_SHM:
@@ -245,12 +245,12 @@ static int drm_addmap_core(struct drm_device * dev, resource_size_t offset,
map->offset = (unsigned long)map->handle;
if (map->flags & _DRM_CONTAINS_LOCK) {
/* Prevent a 2nd X Server from creating a 2nd lock */
- if (dev->primary->master->lock.hw_lock != NULL) {
+ if (dev->master->lock.hw_lock != NULL) {
vfree(map->handle);
kfree(map);
return -EBUSY;
}
- dev->sigdata.lock = dev->primary->master->lock.hw_lock = map->handle; /* Pointer to lock */
+ dev->sigdata.lock = dev->master->lock.hw_lock = map->handle; /* Pointer to lock */
}
break;
case _DRM_AGP: {
@@ -356,7 +356,7 @@ static int drm_addmap_core(struct drm_device * dev, resource_size_t offset,
mutex_unlock(&dev->struct_mutex);
if (!(map->flags & _DRM_DRIVER))
- list->master = dev->primary->master;
+ list->master = dev->master;
*maplist = list;
return 0;
}
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 0bac5246e5a7..0a06f9120b5a 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -464,7 +464,7 @@ static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
/* Sometimes user space wants everything disabled, so don't steal the
* display if there's a master. */
- if (dev->primary->master)
+ if (READ_ONCE(dev->master))
return false;
drm_for_each_crtc(crtc, dev) {
diff --git a/drivers/gpu/drm/drm_info.c b/drivers/gpu/drm/drm_info.c
index 0090d5987801..24c80dd13837 100644
--- a/drivers/gpu/drm/drm_info.c
+++ b/drivers/gpu/drm/drm_info.c
@@ -50,9 +50,12 @@ int drm_name_info(struct seq_file *m, void *data)
struct drm_info_node *node = (struct drm_info_node *) m->private;
struct drm_minor *minor = node->minor;
struct drm_device *dev = minor->dev;
- struct drm_master *master = minor->master;
+ struct drm_master *master;
+
+ mutex_lock(&dev->master_mutex);
+ master = dev->master;
if (!master)
- return 0;
+ goto out_unlock;
if (master->unique) {
seq_printf(m, "%s %s %s\n",
@@ -62,6 +65,9 @@ int drm_name_info(struct seq_file *m, void *data)
seq_printf(m, "%s %s\n",
dev->driver->name, dev_name(dev->dev));
}
+out_unlock:
+ mutex_unlock(&dev->master_mutex);
+
return 0;
}
diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
index 0fb8f9e73486..ae0a4d39deec 100644
--- a/drivers/gpu/drm/drm_lock.c
+++ b/drivers/gpu/drm/drm_lock.c
@@ -334,7 +334,7 @@ void drm_legacy_lock_release(struct drm_device *dev, struct file *filp)
struct drm_file *file_priv = filp->private_data;
/* if the master has gone away we can't do anything with the lock */
- if (!file_priv->minor->master)
+ if (!dev->master)
return;
if (drm_legacy_i_have_hw_lock(dev, file_priv)) {
diff --git a/drivers/gpu/drm/sis/sis_mm.c b/drivers/gpu/drm/sis/sis_mm.c
index 93ad8a5704d1..03defda77766 100644
--- a/drivers/gpu/drm/sis/sis_mm.c
+++ b/drivers/gpu/drm/sis/sis_mm.c
@@ -316,7 +316,7 @@ void sis_reclaim_buffers_locked(struct drm_device *dev,
struct sis_file_private *file_priv = file->driver_priv;
struct sis_memblock *entry, *next;
- if (!(file->minor->master && file->master->lock.hw_lock))
+ if (!(dev->master && file->master->lock.hw_lock))
return;
drm_legacy_idlelock_take(&file->master->lock);
diff --git a/drivers/gpu/drm/via/via_mm.c b/drivers/gpu/drm/via/via_mm.c
index 4f20742e7788..a04ef1c992d9 100644
--- a/drivers/gpu/drm/via/via_mm.c
+++ b/drivers/gpu/drm/via/via_mm.c
@@ -208,7 +208,7 @@ void via_reclaim_buffers_locked(struct drm_device *dev,
struct via_file_private *file_priv = file->driver_priv;
struct via_memblock *entry, *next;
- if (!(file->minor->master && file->master->lock.hw_lock))
+ if (!(dev->master && file->master->lock.hw_lock))
return;
drm_legacy_idlelock_take(&file->master->lock);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index e8788d7b29dc..62e0e70cb5a2 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -336,7 +336,7 @@ struct drm_file {
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 drm_minor {
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_device {
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 */
--
2.8.1
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