diff options
Diffstat (limited to 'drivers/infiniband/core/restrack.c')
| -rw-r--r-- | drivers/infiniband/core/restrack.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c index ac3688952cab..cfee2071586c 100644 --- a/drivers/infiniband/core/restrack.c +++ b/drivers/infiniband/core/restrack.c @@ -71,6 +71,8 @@ int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type, xa_lock(&rt->xa); xas_for_each(&xas, e, U32_MAX) { + if (xa_is_zero(e)) + continue; if (xa_get_mark(&rt->xa, e->id, RESTRACK_DD) && !show_details) continue; cnt++; @@ -277,6 +279,53 @@ int rdma_restrack_put(struct rdma_restrack_entry *res) EXPORT_SYMBOL(rdma_restrack_put); /** + * rdma_restrack_sync() - Fence concurrent netlink dumps on an entry + * @res: resource entry + * + * After this returns any concurrent netlink dump threads will see the current + * value of the object. This is useful if the object has to be changed and there + * is not locking to protect the nl side. Eg for mr->pd. This effectively + * destroys the object from a kref/xarray perspective and then immediately + * restores it. The kref is acting like a lock to barrier concurrent nl threads. + * Callers must ensure rdma_restrack_del() is not concurrently called. + */ +void rdma_restrack_sync(struct rdma_restrack_entry *res) +{ + struct rdma_restrack_entry *old; + struct rdma_restrack_root *rt; + struct task_struct *task; + struct ib_device *dev; + + if (!res->valid || res->no_track) + return; + + dev = res_to_dev(res); + if (WARN_ON(!dev)) + return; + + rt = &dev->res[res->type]; + if (WARN_ON(xa_get_mark(&rt->xa, res->id, RESTRACK_DD))) + return; + + old = xa_cmpxchg(&rt->xa, res->id, res, XA_ZERO_ENTRY, GFP_KERNEL); + if (WARN_ON(old != res)) + return; + + task = res->task; + if (task) + get_task_struct(task); + rdma_restrack_put(res); + wait_for_completion(&res->comp); + reinit_completion(&res->comp); + if (task) + res->task = task; + kref_init(&res->kref); + + xa_cmpxchg(&rt->xa, res->id, XA_ZERO_ENTRY, res, GFP_KERNEL); +} +EXPORT_SYMBOL(rdma_restrack_sync); + +/** * rdma_restrack_del() - delete object from the resource tracking database * @res: resource entry */ |