[PATCH 2/2] drm/panfrost: Fix race when restoring reset state in perfcnt

[Adrián Larumbe]

struct panfrost_perfcnt::state should always be updated atomically, both
in the dump ioctl and the reset sequence.

Fixes: 9944dd07f3cf ("drm/panfrost: Fix races between perfcnt and reset sequence")
Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
index b26da057a1a0..d50b6cc2ecfa 100644
--- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
+++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
@@ -148,18 +148,17 @@ static int panfrost_perfcnt_dump_locked(struct panfrost_device *pfdev, u32 *stat
 	 */
 	ret = wait_for_completion_interruptible_timeout(&pfdev->perfcnt->dump_comp,
 							msecs_to_jiffies(1000));
-
 	if (!ret)
 		ret = -ETIMEDOUT;
 
-	/* We need to restore perfcnt state so the next successful dump can relay it to UM */
-	if (ret < 0) {
-		perfcnt->state |= *state;
-		*state = 0;
-		return ret;
-	}
-
 	scoped_guard(rwsem_read, &pfdev->reset.lock) {
+		/* Restore perfcnt state so the next successful dump can relay it to UM */
+		if (ret < 0) {
+			perfcnt->state |= *state;
+			*state = 0;
+			return ret;
+		}
+
 		*state |= perfcnt->state;
 
 		/* UM must re-enable their session before requesting new dumps. */

-- 
2.55.0