Re: linux-next: build failure after merge of the xarray tree

[Matthew Wilcox]

On Thu, Feb 21, 2019 at 12:34:42PM +0000, Leon Romanovsky wrote:
> On Thu, Feb 21, 2019 at 05:13:32PM +1100, Stephen Rothwell wrote:
> > Hi all,
> >
> > After merging the xarray tree, today's linux-next build (powerpc
> > ppc64_defconfig) failed like this:

[API change]

So I ended up being really busy last week and not having time to send
my merge request for XArray yet.  I'm going to send a request this week;
Leon and Jason, how does this merge resolution look?

Compile tested only.

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index a9f29156e486..8a93c0c95953 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -668,19 +668,10 @@ static int assign_name(struct ib_device *device, const 
char *name)
        }
        strlcpy(device->name, dev_name(&device->dev), IB_DEVICE_NAME_MAX);
 
-       /* Cyclically allocate a user visible ID for the device */
-       device->index = last_id;
-       ret = xa_alloc(&devices, &device->index, INT_MAX, device, GFP_KERNEL);
-       if (ret == -ENOSPC) {
-               device->index = 0;
-               ret = xa_alloc(&devices, &device->index, INT_MAX, device,
-                              GFP_KERNEL);
-       }
-       if (ret)
-               goto out;
-       last_id = device->index + 1;
-
-       ret = 0;
+       ret = xa_alloc_cyclic(&devices, &device->index, device, xa_limit_31b,
+                       &last_id, GFP_KERNEL);
+       if (ret > 0)
+               ret = 0;
 
 out:
        up_write(&devices_rwsem);
@@ -1059,14 +1050,14 @@ static int assign_client_id(struct ib_client *client)
         * to get the LIFO order. The extra linked list can go away if xarray
         * learns to reverse iterate.
         */
-       if (list_empty(&client_list))
+       if (list_empty(&client_list)) {
                client->client_id = 0;
-       else
-               client->client_id =
-                       list_last_entry(&client_list, struct ib_client, list)
-                               ->client_id;
-       ret = xa_alloc(&clients, &client->client_id, INT_MAX, client,
-                      GFP_KERNEL);
+       } else {
+               struct ib_client *last = list_last_entry(&client_list,
+                               struct ib_client, list);
+               client->client_id = last->client_id + 1;
+       }
+       ret = xa_insert(&clients, client->client_id, client, GFP_KERNEL);
        if (ret)
                goto out;
 
diff --git a/drivers/infiniband/core/restrack.c 
b/drivers/infiniband/core/restrack.c
index fa804093fafb..3b5ff2f7b5f8 100644
--- a/drivers/infiniband/core/restrack.c
+++ b/drivers/infiniband/core/restrack.c
@@ -13,28 +13,6 @@
 #include "cma_priv.h"
 #include "restrack.h"
 
-static int rt_xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry,
-                             u32 *next)
-{
-       int err;
-
-       *id = *next;
-       if (*next == U32_MAX)
-               *id = 0;
-
-       xa_lock(xa);
-       err = __xa_alloc(xa, id, U32_MAX, entry, GFP_KERNEL);
-       if (err && *next != U32_MAX) {
-               *id = 0;
-               err = __xa_alloc(xa, id, *next, entry, GFP_KERNEL);
-       }
-
-       if (!err)
-               *next = *id + 1;
-       xa_unlock(xa);
-       return err;
-}
-
 /**
  * rdma_restrack_init() - initialize and allocate resource tracking
  * @dev:  IB device
@@ -226,7 +204,8 @@ static void rdma_restrack_add(struct rdma_restrack_entry 
*res)
        kref_init(&res->kref);
        init_completion(&res->comp);
        if (res->type != RDMA_RESTRACK_QP)
-               ret = rt_xa_alloc_cyclic(&rt->xa, &res->id, res, &rt->next_id);
+               ret = xa_alloc_cyclic(&rt->xa, &res->id, res, xa_limit_32b,
+                               &rt->next_id, GFP_KERNEL);
        else {
                /* Special case to ensure that LQPN points to right QP */
                struct ib_qp *qp = container_of(res, struct ib_qp, res);