The master_lookup_lock spinlock can be useful as an inner lock for
other attributes that are currently protected by
drm_device.master_mutex.
However, since the spinlock belongs to struct drm_file, its use case
is limited to serializing accesses by a single drm_file. Moving this
lock into struct drm_device allows us to use it for structures that
are accessed by multiple drm_files, such as drm_master.magic_map.
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@xxxxxxxxx>
---
drivers/gpu/drm/drm_auth.c | 18 +++++++++---------
drivers/gpu/drm/drm_drv.c | 1 +
drivers/gpu/drm/drm_file.c | 1 -
include/drm/drm_device.h | 3 +++
include/drm/drm_file.h | 10 ++++------
5 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 60a6b21474b1..8efb58aa7d95 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -63,7 +63,7 @@
static bool drm_is_current_master_locked(struct drm_file *fpriv)
{
- lockdep_assert_once(lockdep_is_held(&fpriv->master_lookup_lock) ||
+ lockdep_assert_once(lockdep_is_held(&fpriv->minor->dev->master_lookup_lock) ||
lockdep_is_held(&fpriv->minor->dev->master_mutex));
return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master;
@@ -83,9 +83,9 @@ bool drm_is_current_master(struct drm_file *fpriv)
{
bool ret;
- spin_lock(&fpriv->master_lookup_lock);
+ spin_lock(&fpriv->minor->dev->master_lookup_lock);
ret = drm_is_current_master_locked(fpriv);
- spin_unlock(&fpriv->master_lookup_lock);
+ spin_unlock(&fpriv->minor->dev->master_lookup_lock);
return ret;
}
@@ -174,9 +174,9 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
new_master = drm_master_create(dev);
if (!new_master)
return -ENOMEM;
- spin_lock(&fpriv->master_lookup_lock);
+ spin_lock(&dev->master_lookup_lock);
fpriv->master = new_master;
- spin_unlock(&fpriv->master_lookup_lock);
+ spin_unlock(&dev->master_lookup_lock);
fpriv->is_master = 1;
fpriv->authenticated = 1;
@@ -338,9 +338,9 @@ int drm_master_open(struct drm_file *file_priv)
if (!dev->master) {
ret = drm_new_set_master(dev, file_priv);
} else {
- spin_lock(&file_priv->master_lookup_lock);
+ spin_lock(&dev->master_lookup_lock);
file_priv->master = drm_master_get(dev->master);
- spin_unlock(&file_priv->master_lookup_lock);
+ spin_unlock(&dev->master_lookup_lock);
}
mutex_unlock(&dev->master_mutex);
@@ -405,13 +405,13 @@ struct drm_master *drm_file_get_master(struct drm_file *file_priv)
{
struct drm_master *master = NULL;
- spin_lock(&file_priv->master_lookup_lock);
+ spin_lock(&file_priv->minor->dev->master_lookup_lock);
if (!file_priv->master)
goto unlock;
master = drm_master_get(file_priv->master);
unlock:
- spin_unlock(&file_priv->master_lookup_lock);
+ spin_unlock(&file_priv->minor->dev->master_lookup_lock);
return master;
}
EXPORT_SYMBOL(drm_file_get_master);
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 7a5097467ba5..218c16f11c80 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -612,6 +612,7 @@ static int drm_dev_init(struct drm_device *dev,
mutex_init(&dev->filelist_mutex);
mutex_init(&dev->clientlist_mutex);
mutex_init(&dev->master_mutex);
+ spin_lock_init(&dev->master_lookup_lock);
ret = drmm_add_action(dev, drm_dev_init_release, NULL);
if (ret)
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index ed25168619fc..b8679bbaea69 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -176,7 +176,6 @@ struct drm_file *drm_file_alloc(struct drm_minor *minor)
init_waitqueue_head(&file->event_wait);
file->event_space = 4096; /* set aside 4k for event buffer */
- spin_lock_init(&file->master_lookup_lock);
mutex_init(&file->event_read_lock);
if (drm_core_check_feature(dev, DRIVER_GEM))
diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
index 604b1d1b2d72..506eb2784819 100644
--- a/include/drm/drm_device.h
+++ b/include/drm/drm_device.h
@@ -152,6 +152,9 @@ struct drm_device {
*/
struct mutex master_mutex;
+ /** @master_lookup_lock: Serializes &drm_file.master. */
+ spinlock_t master_lookup_lock;
+
/**
* @open_count:
*
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index a3acb7ac3550..0536e9612a46 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -227,15 +227,16 @@ struct drm_file {
* @master:
*
* Master this node is currently associated with. Protected by struct
- * &drm_device.master_mutex, and serialized by @master_lookup_lock.
+ * &drm_device.master_mutex, and serialized by
+ * &drm_device.master_lookup_lock.
*
* Only relevant if drm_is_primary_client() returns true. Note that
* this only matches &drm_device.master if the master is the currently
* active one.
*
* To update @master, both &drm_device.master_mutex and
- * @master_lookup_lock need to be held, therefore holding either of
- * them is safe and enough for the read side.
+ * &drm_device.master_lookup_lock need to be held, therefore holding
+ * either of them is safe and enough for the read side.
*
* When dereferencing this pointer, either hold struct
* &drm_device.master_mutex for the duration of the pointer's use, or
@@ -248,9 +249,6 @@ struct drm_file {
*/
struct drm_master *master;
- /** @master_lock: Serializes @master. */
- spinlock_t master_lookup_lock;
-
/** @pid: Process that opened this file. */
struct pid *pid;
--
2.25.1
