migrate_disable() and rcu_read_lock() are used to together in many case in
bpf. However, when PREEMPT_RCU is not enabled, rcu_read_lock() indicate
migrate_disable(), so we don't need to call it in this case.

In this series, we introduce rcu_migrate_disable and rcu_migrate_enable,
which will call migrate_disable and migrate_enable only when PREEMPT_RCU
enabled. And replace the migrate_enable/migrate_disable with
rcu_migrate_enable/rcu_migrate_disable in bpf.

Menglong Dong (7):
  rcu: add rcu_migrate_enable and rcu_migrate_disable
  bpf: use rcu_migrate_* for bpf_cgrp_storage_free()
  bpf: use rcu_migrate_* for bpf_inode_storage_free()
  bpf: use rcu_migrate_* for bpf_iter_run_prog()
  bpf: use rcu_migrate_* for bpf_task_storage_free()
  bpf: use rcu_migrate_* for bpf_prog_run_array_cg()
  bpf: use rcu_migrate_* for trampoline.c

 include/linux/rcupdate.h       | 18 ++++++++++++++++++
 kernel/bpf/bpf_cgrp_storage.c  |  4 ++--
 kernel/bpf/bpf_inode_storage.c |  4 ++--
 kernel/bpf/bpf_iter.c          |  4 ++--
 kernel/bpf/bpf_task_storage.c  |  4 ++--
 kernel/bpf/cgroup.c            |  4 ++--
 kernel/bpf/trampoline.c        | 12 ++++++------
 7 files changed, 34 insertions(+), 16 deletions(-)

-- 
2.50.1