drm/amd/display: Fix deadlock when flushing irq

Lock irq table when reading a work in queue,
unlock to flush the work, lock again till all tasks
are cleared

Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c

@@ -329,14 +329,15 @@ void amdgpu_dm_irq_fini(struct amdgpu_device *adev)
 {
 	int src;
 	struct irq_list_head *lh;
+	unsigned long irq_table_flags;
 	DRM_DEBUG_KMS("DM_IRQ: releasing resources.\n");
-
 	for (src = 0; src < DAL_IRQ_SOURCES_NUMBER; src++) {
-
+		DM_IRQ_TABLE_LOCK(adev, irq_table_flags);
 		/* The handler was removed from the table,
 		 * it means it is safe to flush all the 'work'
 		 * (because no code can schedule a new one). */
 		lh = &adev->dm.irq_handler_list_low_tab[src];
+		DM_IRQ_TABLE_UNLOCK(adev, irq_table_flags);
 		flush_work(&lh->work);
 	}
 }