diff options
Diffstat (limited to 'drivers/infiniband/core/rdma_core.c')
-rw-r--r-- | drivers/infiniband/core/rdma_core.c | 38 |
1 files changed, 28 insertions, 10 deletions
diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c index 85b5ee4defa4..d8eead5d106d 100644 --- a/drivers/infiniband/core/rdma_core.c +++ b/drivers/infiniband/core/rdma_core.c @@ -141,7 +141,12 @@ static struct ib_uobject *alloc_uobj(struct ib_ucontext *context, */ uobj->context = context; uobj->type = type; - atomic_set(&uobj->usecnt, 0); + /* + * Allocated objects start out as write locked to deny any other + * syscalls from accessing them until they are committed. See + * rdma_alloc_commit_uobject + */ + atomic_set(&uobj->usecnt, -1); kref_init(&uobj->ref); return uobj; @@ -196,7 +201,15 @@ static struct ib_uobject *lookup_get_idr_uobject(const struct uverbs_obj_type *t goto free; } - uverbs_uobject_get(uobj); + /* + * The idr_find is guaranteed to return a pointer to something that + * isn't freed yet, or NULL, as the free after idr_remove goes through + * kfree_rcu(). However the object may still have been released and + * kfree() could be called at any time. + */ + if (!kref_get_unless_zero(&uobj->ref)) + uobj = ERR_PTR(-ENOENT); + free: rcu_read_unlock(); return uobj; @@ -399,13 +412,13 @@ static int __must_check remove_commit_fd_uobject(struct ib_uobject *uobj, return ret; } -static void lockdep_check(struct ib_uobject *uobj, bool exclusive) +static void assert_uverbs_usecnt(struct ib_uobject *uobj, bool exclusive) { #ifdef CONFIG_LOCKDEP if (exclusive) - WARN_ON(atomic_read(&uobj->usecnt) > 0); + WARN_ON(atomic_read(&uobj->usecnt) != -1); else - WARN_ON(atomic_read(&uobj->usecnt) == -1); + WARN_ON(atomic_read(&uobj->usecnt) <= 0); #endif } @@ -444,7 +457,7 @@ int __must_check rdma_remove_commit_uobject(struct ib_uobject *uobj) WARN(true, "ib_uverbs: Cleanup is running while removing an uobject\n"); return 0; } - lockdep_check(uobj, true); + assert_uverbs_usecnt(uobj, true); ret = _rdma_remove_commit_uobject(uobj, RDMA_REMOVE_DESTROY); up_read(&ucontext->cleanup_rwsem); @@ -474,16 +487,17 @@ int rdma_explicit_destroy(struct ib_uobject *uobject) WARN(true, "ib_uverbs: Cleanup is running while removing an uobject\n"); return 0; } - lockdep_check(uobject, true); + assert_uverbs_usecnt(uobject, true); ret = uobject->type->type_class->remove_commit(uobject, RDMA_REMOVE_DESTROY); if (ret) - return ret; + goto out; uobject->type = &null_obj_type; +out: up_read(&ucontext->cleanup_rwsem); - return 0; + return ret; } static void alloc_commit_idr_uobject(struct ib_uobject *uobj) @@ -527,6 +541,10 @@ int rdma_alloc_commit_uobject(struct ib_uobject *uobj) return ret; } + /* matches atomic_set(-1) in alloc_uobj */ + assert_uverbs_usecnt(uobj, true); + atomic_set(&uobj->usecnt, 0); + uobj->type->type_class->alloc_commit(uobj); up_read(&uobj->context->cleanup_rwsem); @@ -561,7 +579,7 @@ static void lookup_put_fd_uobject(struct ib_uobject *uobj, bool exclusive) void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool exclusive) { - lockdep_check(uobj, exclusive); + assert_uverbs_usecnt(uobj, exclusive); uobj->type->type_class->lookup_put(uobj, exclusive); /* * In order to unlock an object, either decrease its usecnt for |