kernel: move use_mm/unuse_mm to kthread.c

cover the newly merged use_mm/unuse_mm caller in vfio

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Felix Kuehling <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Zhenyu Wang <[email protected]>
Cc: Zhi Wang <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

Author: Christoph Hellwig

drivers/vfio/vfio_iommu_type1.c

@@ -27,7 +27,7 @@
 #include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/mm.h>
-#include <linux/mmu_context.h>
+#include <linux/kthread.h>
 #include <linux/rbtree.h>
 #include <linux/sched/signal.h>
 #include <linux/sched/mm.h>