xen: Convert pvcalls-back to XArray

Pull the XArray out from under the semaphore as it is serialised by its
own spinlock.  In pvcalls_back_release(), it's more efficient to erase
the element than to load it then erase it if it was present.

Signed-off-by: Matthew Wilcox <willy@infradead.org>

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 69a626b0e59420443b3972426c2d8be19714589c..c741075167c843f97f839e8c7db19743f8d700e2 100644 (file)
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -6,10 +6,10 @@
 #include <linux/inet.h>
 #include <linux/kthread.h>
 #include <linux/list.h>
-#include <linux/radix-tree.h>
 #include <linux/module.h>
 #include <linux/semaphore.h>
 #include <linux/wait.h>
+#include <linux/xarray.h>
 #include <net/sock.h>
 #include <net/inet_common.h>
 #include <net/inet_connection_sock.h>
@@ -41,7 +41,7 @@ struct pvcalls_fedata {
        struct xen_pvcalls_back_ring ring;
        int irq;
        struct list_head socket_mappings;
-       struct radix_tree_root socketpass_mappings;
+       struct xarray socketpass_mappings;
        struct semaphore socket_lock;
 };
 
@@ -368,8 +368,8 @@ static struct sock_mapping *pvcalls_new_active_socket(
 out:
        down(&fedata->socket_lock);
        list_del(&map->list);
-       pvcalls_back_release_active(fedata->dev, fedata, map);
        up(&fedata->socket_lock);
+       pvcalls_back_release_active(fedata->dev, fedata, map);
        return NULL;
 }
 
@@ -482,14 +482,10 @@ static int pvcalls_back_release(struct xenbus_device *dev,
                        goto out;
                }
        }
-       mappass = radix_tree_lookup(&fedata->socketpass_mappings,
-                                   req->u.release.id);
-       if (mappass != NULL) {
-               radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
-               up(&fedata->socket_lock);
+       up(&fedata->socket_lock);
+       mappass = xa_erase(&fedata->socketpass_mappings, req->u.release.id);
+       if (mappass)
                ret = pvcalls_back_release_passive(dev, fedata, mappass);
-       } else
-               up(&fedata->socket_lock);
 
 out:
        rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
@@ -640,10 +636,8 @@ static int pvcalls_back_bind(struct xenbus_device *dev,
        map->fedata = fedata;
        map->id = req->u.bind.id;
 
-       down(&fedata->socket_lock);
-       ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
-                               map);
-       up(&fedata->socket_lock);
+       ret = xa_err(xa_store(&fedata->socketpass_mappings, map->id, map,
+                                                               GFP_KERNEL));
        if (ret)
                goto out;
 
@@ -679,9 +673,7 @@ static int pvcalls_back_listen(struct xenbus_device *dev,
 
        fedata = dev_get_drvdata(&dev->dev);
 
-       down(&fedata->socket_lock);
-       map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
-       up(&fedata->socket_lock);
+       map = xa_load(&fedata->socketpass_mappings, req->u.listen.id);
        if (map == NULL)
                goto out;
 
@@ -707,10 +699,7 @@ static int pvcalls_back_accept(struct xenbus_device *dev,
 
        fedata = dev_get_drvdata(&dev->dev);
 
-       down(&fedata->socket_lock);
-       mappass = radix_tree_lookup(&fedata->socketpass_mappings,
-               req->u.accept.id);
-       up(&fedata->socket_lock);
+       mappass = xa_load(&fedata->socketpass_mappings, req->u.accept.id);
        if (mappass == NULL)
                goto out_error;
 
@@ -755,10 +744,7 @@ static int pvcalls_back_poll(struct xenbus_device *dev,
 
        fedata = dev_get_drvdata(&dev->dev);
 
-       down(&fedata->socket_lock);
-       mappass = radix_tree_lookup(&fedata->socketpass_mappings,
-                                   req->u.poll.id);
-       up(&fedata->socket_lock);
+       mappass = xa_load(&fedata->socketpass_mappings, req->u.poll.id);
        if (mappass == NULL)
                return -EINVAL;
 
@@ -950,7 +936,7 @@ static int backend_connect(struct xenbus_device *dev)
        fedata->dev = dev;
 
        INIT_LIST_HEAD(&fedata->socket_mappings);
-       INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
+       xa_init(&fedata->socketpass_mappings);
        sema_init(&fedata->socket_lock, 1);
        dev_set_drvdata(&dev->dev, fedata);
 
@@ -974,9 +960,7 @@ static int backend_disconnect(struct xenbus_device *dev)
        struct pvcalls_fedata *fedata;
        struct sock_mapping *map, *n;
        struct sockpass_mapping *mappass;
-       struct radix_tree_iter iter;
-       void **slot;
-
+       unsigned long index;
 
        fedata = dev_get_drvdata(&dev->dev);
 
@@ -985,21 +969,12 @@ static int backend_disconnect(struct xenbus_device *dev)
                list_del(&map->list);
                pvcalls_back_release_active(dev, fedata, map);
        }
+       up(&fedata->socket_lock);
 
-       radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
-               mappass = radix_tree_deref_slot(slot);
-               if (!mappass)
-                       continue;
-               if (radix_tree_exception(mappass)) {
-                       if (radix_tree_deref_retry(mappass))
-                               slot = radix_tree_iter_retry(&iter);
-               } else {
-                       radix_tree_delete(&fedata->socketpass_mappings,
-                                         mappass->id);
-                       pvcalls_back_release_passive(dev, fedata, mappass);
-               }
+       xa_for_each(&fedata->socketpass_mappings, index, mappass) {
+               xa_erase(&fedata->socketpass_mappings, index);
+               pvcalls_back_release_passive(dev, fedata, mappass);
        }
-       up(&fedata->socket_lock);
 
        unbind_from_irqhandler(fedata->irq, dev);
        xenbus_unmap_ring_vfree(dev, fedata->sring);