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| author | Jason Gunthorpe <jgg@mellanox.com> | 2018-09-16 20:48:09 +0300 |
|---|---|---|
| committer | Doug Ledford <dledford@redhat.com> | 2018-09-21 11:58:36 -0400 |
| commit | ca748c39ea3f3c755295d64d69ba0b4375e34b5d (patch) | |
| tree | 64bbe9e8457d512169ead7e8fa43bff77958eab0 /include/rdma | |
| parent | f27a0d50a4bc2861b472c2e3740d63a29d1ac460 (diff) | |
| download | linux-ca748c39ea3f3c755295d64d69ba0b4375e34b5d.tar.gz linux-ca748c39ea3f3c755295d64d69ba0b4375e34b5d.tar.bz2 linux-ca748c39ea3f3c755295d64d69ba0b4375e34b5d.zip | |
RDMA/umem: Get rid of per_mm->notifier_count
This is intrinsically racy and the scheme is simply unnecessary. New MR
registration can wait for any on going invalidation to fully complete.
CPU0 CPU1
if (atomic_read())
if (atomic_dec_and_test() &&
!list_empty())
{ /* not taken */ }
list_add()
Putting the new UMEM into some kind of purgatory until another invalidate
rolls through..
Instead hold the read side of the umem_rwsem across the pair'd start/end
and get rid of the racy 'deferred add' approach.
Since all umem's in the rbt are always ready to go, also get rid of the
mn_counters_active stuff.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'include/rdma')
| -rw-r--r-- | include/rdma/ib_umem_odp.h | 15 |
1 files changed, 0 insertions, 15 deletions
diff --git a/include/rdma/ib_umem_odp.h b/include/rdma/ib_umem_odp.h index 259eb08dfc9e..ce9502545903 100644 --- a/include/rdma/ib_umem_odp.h +++ b/include/rdma/ib_umem_odp.h @@ -67,15 +67,9 @@ struct ib_umem_odp { struct mutex umem_mutex; void *private; /* for the HW driver to use. */ - /* When false, use the notifier counter in the ucontext struct. */ - bool mn_counters_active; int notifiers_seq; int notifiers_count; - /* A linked list of umems that don't have private mmu notifier - * counters yet. */ - struct list_head no_private_counters; - /* Tree tracking */ struct umem_odp_node interval_tree; @@ -99,11 +93,8 @@ struct ib_ucontext_per_mm { struct rb_root_cached umem_tree; /* Protects umem_tree */ struct rw_semaphore umem_rwsem; - atomic_t notifier_count; struct mmu_notifier mn; - /* A list of umems that don't have private mmu notifier counters yet. */ - struct list_head no_private_counters; unsigned int odp_mrs_count; struct list_head ucontext_list; @@ -162,12 +153,6 @@ static inline int ib_umem_mmu_notifier_retry(struct ib_umem_odp *umem_odp, * and the ucontext umem_mutex semaphore locked for read). */ - /* Do not allow page faults while the new ib_umem hasn't seen a state - * with zero notifiers yet, and doesn't have its own valid set of - * private counters. */ - if (!umem_odp->mn_counters_active) - return 1; - if (unlikely(umem_odp->notifiers_count)) return 1; if (umem_odp->notifiers_seq != mmu_seq) |