RDMA/restrack: Reduce scope of synchronization lock while updating DB

XArray uses internal lock for updates to XArray. This means that our
external RW lock is needed to ensure that entry is not deleted while we
are performing iteration over list.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c
index ac97167..076ef64 100644 (file)
--- a/drivers/infiniband/core/restrack.c
+++ b/drivers/infiniband/core/restrack.c
@@ -210,13 +210,11 @@ static void rdma_restrack_add(struct rdma_restrack_entry *res)
        kref_init(&res->kref);
        init_completion(&res->comp);
 
-       down_write(&dev->res.rwsem);
        ret = rt_xa_alloc_cyclic(&dev->res.xa[res->type], &res->id, res,
                                 &dev->res.next_id[res->type]);
 
        if (!ret)
                res->valid = true;
-       up_write(&dev->res.rwsem);
 }
 
 /**

diff --git a/include/rdma/restrack.h b/include/rdma/restrack.h
index 44ce32c..53e1a7f 100644 (file)
--- a/include/rdma/restrack.h
+++ b/include/rdma/restrack.h
@@ -58,7 +58,8 @@ struct rdma_restrack_entry;
  */
 struct rdma_restrack_root {
        /*
-        * @rwsem: Read/write lock to protect lists
+        * @rwsem: Read/write lock to protect erase of entry.
+        * Lists and insertions are protected by XArray internal lock.
         */
        struct rw_semaphore     rwsem;
        /**