[PATCH v2] drm/xe: Remove unwanted mutex locking

[Niranjana Vishwanathapura]

Do not hold xef->exec_queue.lock mutex while parsing the xarray
xef->exec_queue.xa in xe_file_close() as it is not needed and
will cause an unwanted dependency between this lock and the vm->lock.

This lock protects the exec queue lookup and reference taking which
doesn't apply to this code path. When FD is closing, IOCTLs presumably
can't be modifying the xarray.

v2: Update commit text

Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
Reviewed-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_device.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index f04b11e45c2d..4cca16f2d4ed 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -96,12 +96,11 @@ static void xe_file_close(struct drm_device *dev, struct drm_file *file)
 	struct xe_exec_queue *q;
 	unsigned long idx;
 
-	mutex_lock(&xef->exec_queue.lock);
+	/* No locking needed here */
 	xa_for_each(&xef->exec_queue.xa, idx, q) {
 		xe_exec_queue_kill(q);
 		xe_exec_queue_put(q);
 	}
-	mutex_unlock(&xef->exec_queue.lock);
 	xa_destroy(&xef->exec_queue.xa);
 	mutex_destroy(&xef->exec_queue.lock);
 	mutex_lock(&xef->vm.lock);
-- 
2.43.0