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RDMA/umem: Restore lockdep check while downgrading lock 

Lockdep engine handles correctly downgrade of locks and it simply
incorrect to disable lockdep checks prior to calling mmu_notifier.

Remove lockdep_off and ensure locks correctness.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
hifive-unleashed-5.1
Leon Romanovsky 2018-09-03 20:17:31 +03:00 committed by Jason Gunthorpe
parent e1f540c3ed
commit 50704e039a
1 changed files with 0 additions and 6 deletions
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6
drivers/infiniband/core/umem_odp.c
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@ -431,13 +431,7 @@ int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem,
atomic_set(&context->notifier_count, 0);
INIT_HLIST_NODE(&context->mn.hlist);
context->mn.ops = &ib_umem_notifiers;
/*
* Lock-dep detects a false positive for mmap_sem vs.
* umem_rwsem, due to not grasping downgrade_write correctly.
*/
lockdep_off();
ret_val = mmu_notifier_register(&context->mn, mm);
lockdep_on();
if (ret_val) {
pr_err("Failed to register mmu_notifier %d\n", ret_val);
ret_val = -EBUSY;