}
/* caller should hold rxe->mcg_lock */
-static struct rxe_mcg *create_grp(struct rxe_dev *rxe,
- struct rxe_pool *pool,
- union ib_gid *mgid)
+static struct rxe_mcg *__rxe_create_grp(struct rxe_dev *rxe,
+ struct rxe_pool *pool,
+ union ib_gid *mgid)
{
- int err;
struct rxe_mcg *grp;
+ int err;
- grp = rxe_alloc_locked(&rxe->mc_grp_pool);
+ grp = rxe_alloc_locked(pool);
if (!grp)
return ERR_PTR(-ENOMEM);
- INIT_LIST_HEAD(&grp->qp_list);
- grp->rxe = rxe;
- rxe_add_key_locked(grp, mgid);
-
err = rxe_mcast_add(rxe, mgid);
if (unlikely(err)) {
- rxe_drop_key_locked(grp);
rxe_drop_ref(grp);
return ERR_PTR(err);
}
+ INIT_LIST_HEAD(&grp->qp_list);
+ grp->rxe = rxe;
+
+ /* rxe_alloc_locked takes a ref on grp but that will be
+ * dropped when grp goes out of scope. We need to take a ref
+ * on the pointer that will be saved in the red-black tree
+ * by rxe_add_key and used to lookup grp from mgid later.
+ * Adding key makes object visible to outside so this should
+ * be done last after the object is ready.
+ */
+ rxe_add_ref(grp);
+ rxe_add_key_locked(grp, mgid);
+
return grp;
}
-static int rxe_mcast_get_grp(struct rxe_dev *rxe, union ib_gid *mgid,
- struct rxe_mcg **grp_p)
+static struct rxe_mcg *rxe_mcast_get_grp(struct rxe_dev *rxe,
+ union ib_gid *mgid)
{
- int err;
struct rxe_mcg *grp;
struct rxe_pool *pool = &rxe->mc_grp_pool;
unsigned long flags;
if (rxe->attr.max_mcast_qp_attach == 0)
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
spin_lock_irqsave(&rxe->mcg_lock, flags);
-
grp = rxe_pool_get_key_locked(pool, mgid);
- if (grp)
- goto done;
-
- grp = create_grp(rxe, pool, mgid);
- if (IS_ERR(grp)) {
- spin_unlock_irqrestore(&rxe->mcg_lock, flags);
- err = PTR_ERR(grp);
- return err;
- }
-
-done:
+ if (!grp)
+ grp = __rxe_create_grp(rxe, pool, mgid);
spin_unlock_irqrestore(&rxe->mcg_lock, flags);
- *grp_p = grp;
- return 0;
+
+ return grp;
}
static int rxe_mcast_add_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
- struct rxe_mcg *grp)
+ struct rxe_mcg *grp)
{
- int err;
- struct rxe_mca *elem;
+ struct rxe_mca *mca, *tmp;
unsigned long flags;
+ int err;
+
+ /* check to see if the qp is already a member of the group */
+ spin_lock_irqsave(&rxe->mcg_lock, flags);
+ list_for_each_entry(mca, &grp->qp_list, qp_list) {
+ if (mca->qp == qp) {
+ spin_unlock_irqrestore(&rxe->mcg_lock, flags);
+ return 0;
+ }
+ }
+ spin_unlock_irqrestore(&rxe->mcg_lock, flags);
+
+ /* speculative alloc new mca without using GFP_ATOMIC */
+ mca = kzalloc(sizeof(*mca), GFP_KERNEL);
+ if (!mca)
+ return -ENOMEM;
- /* check to see of the qp is already a member of the group */
spin_lock_irqsave(&rxe->mcg_lock, flags);
- list_for_each_entry(elem, &grp->qp_list, qp_list) {
- if (elem->qp == qp) {
+ /* re-check to see if someone else just attached qp */
+ list_for_each_entry(tmp, &grp->qp_list, qp_list) {
+ if (tmp->qp == qp) {
+ kfree(mca);
err = 0;
goto out;
}
}
+ /* check limits after checking if already attached */
if (grp->num_qp >= rxe->attr.max_mcast_qp_attach) {
+ kfree(mca);
err = -ENOMEM;
goto out;
}
- elem = rxe_alloc_locked(&rxe->mc_elem_pool);
- if (!elem) {
- err = -ENOMEM;
- goto out;
- }
+ /* protect pointer to qp in mca */
+ rxe_add_ref(qp);
+ mca->qp = qp;
- /* each qp holds a ref on the grp */
- rxe_add_ref(grp);
-
- grp->num_qp++;
- elem->qp = qp;
atomic_inc(&qp->mcg_num);
-
- list_add(&elem->qp_list, &grp->qp_list);
+ grp->num_qp++;
+ list_add(&mca->qp_list, &grp->qp_list);
err = 0;
out:
return err;
}
+/* caller should be holding rxe->mcg_lock */
+static void __rxe_destroy_grp(struct rxe_mcg *grp)
+{
+ /* first remove grp from red-black tree then drop ref */
+ rxe_drop_key_locked(grp);
+ rxe_drop_ref(grp);
+
+ rxe_mcast_delete(grp->rxe, &grp->mgid);
+}
+
+static void rxe_destroy_grp(struct rxe_mcg *grp)
+{
+ struct rxe_dev *rxe = grp->rxe;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rxe->mcg_lock, flags);
+ __rxe_destroy_grp(grp);
+ spin_unlock_irqrestore(&rxe->mcg_lock, flags);
+}
+
+void rxe_mc_cleanup(struct rxe_pool_elem *elem)
+{
+ /* nothing left to do for now */
+}
+
static int rxe_mcast_drop_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
union ib_gid *mgid)
{
struct rxe_mcg *grp;
- struct rxe_mca *elem, *tmp;
+ struct rxe_mca *mca, *tmp;
unsigned long flags;
-
- grp = rxe_pool_get_key(&rxe->mc_grp_pool, mgid);
- if (!grp)
- goto err1;
+ int err;
spin_lock_irqsave(&rxe->mcg_lock, flags);
+ grp = rxe_pool_get_key_locked(&rxe->mc_grp_pool, mgid);
+ if (!grp) {
+ /* we didn't find the mcast group for mgid */
+ err = -EINVAL;
+ goto out_unlock;
+ }
- list_for_each_entry_safe(elem, tmp, &grp->qp_list, qp_list) {
- if (elem->qp == qp) {
- list_del(&elem->qp_list);
+ list_for_each_entry_safe(mca, tmp, &grp->qp_list, qp_list) {
+ if (mca->qp == qp) {
+ list_del(&mca->qp_list);
+
+ /* if the number of qp's attached to the
+ * mcast group falls to zero go ahead and
+ * tear it down. This will not free the
+ * object since we are still holding a ref
+ * from the get key above.
+ */
grp->num_qp--;
+ if (grp->num_qp <= 0)
+ __rxe_destroy_grp(grp);
+
atomic_dec(&qp->mcg_num);
- spin_unlock_irqrestore(&rxe->mcg_lock, flags);
- rxe_drop_ref(elem);
- rxe_drop_ref(grp); /* ref held by QP */
- rxe_drop_ref(grp); /* ref from get_key */
- return 0;
+ /* drop the ref from get key. This will free the
+ * object if num_qp is zero.
+ */
+ rxe_drop_ref(grp);
+ kfree(mca);
+ err = 0;
+ goto out_unlock;
}
}
- spin_unlock_irqrestore(&rxe->mcg_lock, flags);
- rxe_drop_ref(grp); /* ref from get_key */
-err1:
- return -EINVAL;
-}
-
-void rxe_mc_cleanup(struct rxe_pool_elem *elem)
-{
- struct rxe_mcg *grp = container_of(elem, typeof(*grp), elem);
- struct rxe_dev *rxe = grp->rxe;
+ /* we didn't find the qp on the list */
+ rxe_drop_ref(grp);
+ err = -EINVAL;
- rxe_drop_key(grp);
- rxe_mcast_delete(rxe, &grp->mgid);
+out_unlock:
+ spin_unlock_irqrestore(&rxe->mcg_lock, flags);
+ return err;
}
int rxe_attach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
struct rxe_mcg *grp;
/* takes a ref on grp if successful */
- err = rxe_mcast_get_grp(rxe, mgid, &grp);
- if (err)
- return err;
+ grp = rxe_mcast_get_grp(rxe, mgid);
+ if (IS_ERR(grp))
+ return PTR_ERR(grp);
err = rxe_mcast_add_grp_elem(rxe, qp, grp);
+ /* if we failed to attach the first qp to grp tear it down */
+ if (grp->num_qp == 0)
+ rxe_destroy_grp(grp);
+
rxe_drop_ref(grp);
return err;
}
projects / linux.git / commitdiff