[Intel-gfx] [PATCH] drm/i915: Drop mutex around clearing error state

[Chris Wilson]

The error state itself is guarded by a spinlock (admittedly even that is
overkill for a single pointer!) and doesn't require us to take the
struct_mutex in the debugfs/sysfs interface. Removing the struct_mutex
removes one more potential blockage when trying to debug a deadlock.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 10 +---------
 drivers/gpu/drm/i915/i915_sysfs.c   | 10 +---------
 2 files changed, 2 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 7124e5666629..e238627c68b6 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -978,17 +978,9 @@ i915_error_state_write(struct file *filp,
 		       loff_t *ppos)
 {
 	struct i915_error_state_file_priv *error_priv = filp->private_data;
-	struct drm_device *dev = error_priv->dev;
-	int ret;
 
 	DRM_DEBUG_DRIVER("Resetting error state\n");
-
-	ret = mutex_lock_interruptible(&dev->struct_mutex);
-	if (ret)
-		return ret;
-
-	i915_destroy_error_state(dev);
-	mutex_unlock(&dev->struct_mutex);
+	i915_destroy_error_state(error_priv->dev);
 
 	return cnt;
 }
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 2d482f677f56..1012eeea1324 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -556,17 +556,9 @@ static ssize_t error_state_write(struct file *file, struct kobject *kobj,
 {
 	struct device *kdev = kobj_to_dev(kobj);
 	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
-	struct drm_device *dev = &dev_priv->drm;
-	int ret;
 
 	DRM_DEBUG_DRIVER("Resetting error state\n");
-
-	ret = mutex_lock_interruptible(&dev->struct_mutex);
-	if (ret)
-		return ret;
-
-	i915_destroy_error_state(dev);
-	mutex_unlock(&dev->struct_mutex);
+	i915_destroy_error_state(&dev_priv->drm);
 
 	return count;
 }
-- 
2.9.3