[PATCH 21/26] drm/i915/perf: always consider holding preemption a privileged op

[Timo Aaltonen]

From: Lionel Landwerlin <lionel.g.landwerlin at intel.com>

BugLink: https://bugs.launchpad.net/bugs/1871957

The ordering of the checks in the existing code can lead to holding
preemption not being considered as privileged op.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Fixes: 9cd20ef7803c ("drm/i915/perf: allow holding preemption on filtered ctx")
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191111095308.2550-1-lionel.g.landwerlin@intel.com
(cherry picked from commit 0b0120d4c7b013eba59b33254febc0a6e4049e13)
Signed-off-by: Timo Aaltonen <timo.aaltonen at canonical.com>
---
 drivers/gpu/drm/i915/i915_perf.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index f5a911d9c53c..b7960fce1460 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -3117,15 +3117,6 @@ i915_perf_open_ioctl_locked(struct i915_perf *perf,
 		}
 	}
 
-	if (props->hold_preemption) {
-		if (!props->single_context) {
-			DRM_DEBUG("preemption disable with no context\n");
-			ret = -EINVAL;
-			goto err;
-		}
-		privileged_op = true;
-	}
-
 	/*
 	 * On Haswell the OA unit supports clock gating off for a specific
 	 * context and in this mode there's no visibility of metrics for the
@@ -3140,9 +3131,18 @@ i915_perf_open_ioctl_locked(struct i915_perf *perf,
 	 * MI_REPORT_PERF_COUNT commands and so consider it a privileged op to
 	 * enable the OA unit by default.
 	 */
-	if (IS_HASWELL(perf->i915) && specific_ctx && !props->hold_preemption)
+	if (IS_HASWELL(perf->i915) && specific_ctx)
 		privileged_op = false;
 
+	if (props->hold_preemption) {
+		if (!props->single_context) {
+			DRM_DEBUG("preemption disable with no context\n");
+			ret = -EINVAL;
+			goto err;
+		}
+		privileged_op = true;
+	}
+
 	/* Similar to perf's kernel.perf_paranoid_cpu sysctl option
 	 * we check a dev.i915.perf_stream_paranoid sysctl option
 	 * to determine if it's ok to access system wide OA counters
-- 
2.25.1