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path: root/drivers/gpu/drm/drm_fops.c
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Diffstat (limited to 'drivers/gpu/drm/drm_fops.c')
-rw-r--r--drivers/gpu/drm/drm_fops.c58
1 files changed, 37 insertions, 21 deletions
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 6b5625e66119..1ea8790e5090 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -226,6 +226,8 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor)
init_waitqueue_head(&priv->event_wait);
priv->event_space = 4096; /* set aside 4k for event buffer */
+ mutex_init(&priv->event_read_lock);
+
if (drm_core_check_feature(dev, DRIVER_GEM))
drm_gem_open(dev, priv);
@@ -511,14 +513,28 @@ ssize_t drm_read(struct file *filp, char __user *buffer,
{
struct drm_file *file_priv = filp->private_data;
struct drm_device *dev = file_priv->minor->dev;
- ssize_t ret = 0;
+ ssize_t ret;
if (!access_ok(VERIFY_WRITE, buffer, count))
return -EFAULT;
- spin_lock_irq(&dev->event_lock);
+ ret = mutex_lock_interruptible(&file_priv->event_read_lock);
+ if (ret)
+ return ret;
+
for (;;) {
- if (list_empty(&file_priv->event_list)) {
+ struct drm_pending_event *e = NULL;
+
+ spin_lock_irq(&dev->event_lock);
+ if (!list_empty(&file_priv->event_list)) {
+ e = list_first_entry(&file_priv->event_list,
+ struct drm_pending_event, link);
+ file_priv->event_space += e->event->length;
+ list_del(&e->link);
+ }
+ spin_unlock_irq(&dev->event_lock);
+
+ if (e == NULL) {
if (ret)
break;
@@ -527,36 +543,36 @@ ssize_t drm_read(struct file *filp, char __user *buffer,
break;
}
- spin_unlock_irq(&dev->event_lock);
+ mutex_unlock(&file_priv->event_read_lock);
ret = wait_event_interruptible(file_priv->event_wait,
!list_empty(&file_priv->event_list));
- spin_lock_irq(&dev->event_lock);
- if (ret < 0)
- break;
-
- ret = 0;
+ if (ret >= 0)
+ ret = mutex_lock_interruptible(&file_priv->event_read_lock);
+ if (ret)
+ return ret;
} else {
- struct drm_pending_event *e;
-
- e = list_first_entry(&file_priv->event_list,
- struct drm_pending_event, link);
- if (e->event->length + ret > count)
+ unsigned length = e->event->length;
+
+ if (length > count - ret) {
+put_back_event:
+ spin_lock_irq(&dev->event_lock);
+ file_priv->event_space -= length;
+ list_add(&e->link, &file_priv->event_list);
+ spin_unlock_irq(&dev->event_lock);
break;
+ }
- if (__copy_to_user_inatomic(buffer + ret,
- e->event, e->event->length)) {
+ if (copy_to_user(buffer + ret, e->event, length)) {
if (ret == 0)
ret = -EFAULT;
- break;
+ goto put_back_event;
}
- file_priv->event_space += e->event->length;
- ret += e->event->length;
- list_del(&e->link);
+ ret += length;
e->destroy(e);
}
}
- spin_unlock_irq(&dev->event_lock);
+ mutex_unlock(&file_priv->event_read_lock);
return ret;
}