[Intel-gfx] [PATCH v7 01/12] drm/i915/perf: ensure we keep a reference on the driver

[Lionel Landwerlin]

The i915 perf stream has its own file descriptor and is tied to
reference of the driver. We haven't taken care of keep the driver
alive.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
Fixes: eec688e1420da5 ("drm/i915: Add i915 perf infrastructure")
---
 drivers/gpu/drm/i915/i915_perf.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 357e63beb373..27842e7bcfed 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -2517,6 +2517,9 @@ static int i915_perf_release(struct inode *inode, struct file *file)
 	i915_perf_destroy_locked(stream);
 	mutex_unlock(&dev_priv->perf.lock);
 
+	/* Release the reference the perf stream kept on the driver. */
+	drm_dev_put(&dev_priv->drm);
+
 	return 0;
 }
 
@@ -2652,6 +2655,11 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
 	if (!(param->flags & I915_PERF_FLAG_DISABLED))
 		i915_perf_enable_locked(stream);
 
+	/* Take a reference on the driver that will be kept with stream_fd
+	 * until its release.
+	 */
+	drm_dev_get(&dev_priv->drm);
+
 	return stream_fd;
 
 err_open:
-- 
2.21.0.392.gf8f6787159e