uverbs: Convert idr to XArray

The word 'idr' is scattered throughout the API, so I haven't changed it,
but the 'idr' variable is now an XArray.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
index e9c905220abdf8cc98eac376ec6b8113e79b9ace..ccf4d069c25c995a1078b31c3892c9585a3143c2 100644 (file)
--- a/drivers/infiniband/core/rdma_core.c
+++ b/drivers/infiniband/core/rdma_core.c
@@ -297,25 +297,13 @@ static struct ib_uobject *alloc_uobj(struct ib_uverbs_file *ufile,
 
 static int idr_add_uobj(struct ib_uobject *uobj)
 {
-       int ret;
-
-       idr_preload(GFP_KERNEL);
-       spin_lock(&uobj->ufile->idr_lock);
-
-       /*
-        * We start with allocating an idr pointing to NULL. This represents an
-        * object which isn't initialized yet. We'll replace it later on with
-        * the real object once we commit.
-        */
-       ret = idr_alloc(&uobj->ufile->idr, NULL, 0,
-                       min_t(unsigned long, U32_MAX - 1, INT_MAX), GFP_NOWAIT);
-       if (ret >= 0)
-               uobj->id = ret;
-
-       spin_unlock(&uobj->ufile->idr_lock);
-       idr_preload_end();
-
-       return ret < 0 ? ret : 0;
+       /*
+        * We start with allocating an idr pointing to NULL. This represents an
+        * object which isn't initialized yet. We'll replace it later on with
+        * the real object once we commit.
+        */
+       return xa_alloc(&uobj->ufile->idr, &uobj->id, NULL, xa_limit_32b,
+                       GFP_KERNEL);
 }
 
 /* Returns the ib_uobject or an error. The caller should check for IS_ERR. */
@@ -325,29 +313,20 @@ lookup_get_idr_uobject(const struct uverbs_api_object *obj,
                       enum rdma_lookup_mode mode)
 {
        struct ib_uobject *uobj;
-       unsigned long idrno = id;
 
        if (id < 0 || id > ULONG_MAX)
                return ERR_PTR(-EINVAL);
 
        rcu_read_lock();
-       /* object won't be released as we're protected in rcu */
-       uobj = idr_find(&ufile->idr, idrno);
-       if (!uobj) {
-               uobj = ERR_PTR(-ENOENT);
-               goto free;
-       }
-
        /*
         * 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 = xa_load(&ufile->idr, id);
+       if (!uobj || !kref_get_unless_zero(&uobj->ref))
                uobj = ERR_PTR(-ENOENT);
-
-free:
        rcu_read_unlock();
        return uobj;
 }
@@ -400,7 +379,7 @@ struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_api_object *obj,
        struct ib_uobject *uobj;
        int ret;
 
-       if (IS_ERR(obj) && PTR_ERR(obj) == -ENOMSG) {
+       if (obj == ERR_PTR(-ENOMSG)) {
                /* must be UVERBS_IDR_ANY_OBJECT, see uapi_get_object() */
                uobj = lookup_get_idr_uobject(NULL, ufile, id, mode);
                if (IS_ERR(uobj))
@@ -461,14 +440,12 @@ alloc_begin_idr_uobject(const struct uverbs_api_object *obj,
        ret = ib_rdmacg_try_charge(&uobj->cg_obj, uobj->context->device,
                                   RDMACG_RESOURCE_HCA_OBJECT);
        if (ret)
-               goto idr_remove;
+               goto remove;
 
        return uobj;
 
-idr_remove:
-       spin_lock(&ufile->idr_lock);
-       idr_remove(&ufile->idr, uobj->id);
-       spin_unlock(&ufile->idr_lock);
+remove:
+       xa_erase(&ufile->idr, uobj->id);
 uobj_put:
        uverbs_uobject_put(uobj);
        return ERR_PTR(ret);
@@ -529,9 +506,7 @@ static void alloc_abort_idr_uobject(struct ib_uobject *uobj)
        ib_rdmacg_uncharge(&uobj->cg_obj, uobj->context->device,
                           RDMACG_RESOURCE_HCA_OBJECT);
 
-       spin_lock(&uobj->ufile->idr_lock);
-       idr_remove(&uobj->ufile->idr, uobj->id);
-       spin_unlock(&uobj->ufile->idr_lock);
+       xa_erase(&uobj->ufile->idr, uobj->id);
 }
 
 static int __must_check destroy_hw_idr_uobject(struct ib_uobject *uobj,
@@ -562,9 +537,7 @@ static int __must_check destroy_hw_idr_uobject(struct ib_uobject *uobj,
 
 static void remove_handle_idr_uobject(struct ib_uobject *uobj)
 {
-       spin_lock(&uobj->ufile->idr_lock);
-       idr_remove(&uobj->ufile->idr, uobj->id);
-       spin_unlock(&uobj->ufile->idr_lock);
+       xa_erase(&uobj->ufile->idr, uobj->id);
        /* Matches the kref in alloc_commit_idr_uobject */
        uverbs_uobject_put(uobj);
 }
@@ -595,17 +568,17 @@ static void remove_handle_fd_uobject(struct ib_uobject *uobj)
 static int alloc_commit_idr_uobject(struct ib_uobject *uobj)
 {
        struct ib_uverbs_file *ufile = uobj->ufile;
+       void *old;
 
-       spin_lock(&ufile->idr_lock);
        /*
         * We already allocated this IDR with a NULL object, so
         * this shouldn't fail.
         *
-        * NOTE: Once we set the IDR we loose ownership of our kref on uobj.
+        * NOTE: Storing the uobj transfers our kref on uobj to the XArray.
         * It will be put by remove_commit_idr_uobject()
         */
-       WARN_ON(idr_replace(&ufile->idr, uobj, uobj->id));
-       spin_unlock(&ufile->idr_lock);
+       old = xa_store(&ufile->idr, uobj->id, uobj, GFP_KERNEL);
+       WARN_ON(old != NULL);
 
        return 0;
 }
@@ -739,29 +712,28 @@ void rdma_lookup_put_uobject(struct ib_uobject *uobj,
 
 void setup_ufile_idr_uobject(struct ib_uverbs_file *ufile)
 {
-       spin_lock_init(&ufile->idr_lock);
-       idr_init(&ufile->idr);
+       xa_init_flags(&ufile->idr, XA_FLAGS_ALLOC);
 }
 
 void release_ufile_idr_uobject(struct ib_uverbs_file *ufile)
 {
        struct ib_uobject *entry;
-       int id;
+       unsigned long id;
 
        /*
         * At this point uverbs_cleanup_ufile() is guaranteed to have run, and
-        * there are no HW objects left, however the IDR is still populated
+        * there are no HW objects left, however the xarray is still populated
         * with anything that has not been cleaned up by userspace. Since the
         * kref on ufile is 0, nothing is allowed to call lookup_get.
         *
         * This is an optimized equivalent to remove_handle_idr_uobject
         */
-       idr_for_each_entry(&ufile->idr, entry, id) {
+       xa_for_each(&ufile->idr, id, entry) {
                WARN_ON(entry->object);
                uverbs_uobject_put(entry);
        }
 
-       idr_destroy(&ufile->idr);
+       xa_destroy(&ufile->idr);
 }
 
 const struct uverbs_obj_type_class uverbs_idr_class = {

diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index d2c29868172cf32e53e255c9447983be9f0b5fc2..1e5aeb39f774df6a1bc386ea448b89763ee1705f 100644 (file)
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -162,9 +162,7 @@ struct ib_uverbs_file {
        struct list_head umaps;
        struct page *disassociate_page;
 
-       struct idr              idr;
-       /* spinlock protects write access to idr */
-       spinlock_t              idr_lock;
+       struct xarray           idr;
 };
 
 struct ib_uverbs_event {