Cleanup rxe_mcast.c code. Minor changes and complete comments.
Signed-off-by: Bob Pearson <rpearsonhpe@xxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_mcast.c | 163 +++++++++++++++++++-------
drivers/infiniband/sw/rxe/rxe_verbs.h | 1 +
2 files changed, 124 insertions(+), 40 deletions(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
index 2fccf69f9a4b..2e5b41063f83 100644
--- a/drivers/infiniband/sw/rxe/rxe_mcast.c
+++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
@@ -175,6 +175,7 @@ static int __rxe_init_mcg(struct rxe_dev *rxe, union ib_gid *mgid,
mcg->rxe = rxe;
mcg->index = rxe->mcg_next++;
+ /* take reference to protect pointer in red-black tree */
kref_get(&mcg->ref_cnt);
__rxe_insert_mcg(mcg);
@@ -263,6 +264,7 @@ void __rxe_destroy_mcg(struct rxe_mcg *mcg)
struct rxe_dev *rxe = mcg->rxe;
__rxe_remove_mcg(mcg);
+ /* drop reference that protected pointer in red-black tree */
kref_put(&mcg->ref_cnt, rxe_cleanup_mcg);
rxe_mcast_delete(rxe, &mcg->mgid);
@@ -282,11 +284,59 @@ static void rxe_destroy_mcg(struct rxe_mcg *mcg)
spin_unlock_bh(&mcg->rxe->mcg_lock);
}
-static int rxe_mcast_add_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
- struct rxe_mcg *mcg)
+/**
+ * __rxe_init_mca - initialize a new mca holding lock
+ * @qp: qp object
+ * @mcg: mcg object
+ * @mca: empty space for new mca
+ *
+ * Context: caller must hold references on qp and mcg, rxe->mcg_lock
+ * and pass memory for new mca
+ *
+ * Returns: 0 on success else an error
+ */
+static int __rxe_init_mca(struct rxe_qp *qp, struct rxe_mcg *mcg,
+ struct rxe_mca *mca)
+{
+ struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+ int n;
+
+ n = atomic_inc_return(&rxe->mcg_attach);
+ if (n > rxe->attr.max_total_mcast_qp_attach) {
+ atomic_dec(&rxe->mcg_attach);
+ return -ENOMEM;
+ }
+
+ n = atomic_inc_return(&mcg->qp_num);
+ if (n > rxe->attr.max_mcast_qp_attach) {
+ atomic_dec(&mcg->qp_num);
+ atomic_dec(&rxe->mcg_attach);
+ return -ENOMEM;
+ }
+
+ atomic_inc(&qp->mcg_num);
+
+ rxe_add_ref(qp);
+ mca->qp = qp;
+
+ list_add_tail(&mca->qp_list, &mcg->qp_list);
+
+ return 0;
+}
+
+/**
+ * rxe_attach_mcg - attach qp to mcg if not already attached
+ * @mcg: mcg object
+ * @qp: qp object
+ *
+ * Context: caller must hold reference on qp and mcg.
+ * Returns: 0 on success else an error
+ */
+static int rxe_attach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp)
{
+ struct rxe_dev *rxe = mcg->rxe;
+ struct rxe_mca *mca, *tmp;
int err;
- struct rxe_mca *mca, *new_mca;
/* check to see if the qp is already a member of the group */
spin_lock_bh(&rxe->mcg_lock);
@@ -298,71 +348,84 @@ static int rxe_mcast_add_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
}
spin_unlock_bh(&rxe->mcg_lock);
- /* speculative alloc new mca without using GFP_ATOMIC */
- new_mca = kzalloc(sizeof(*mca), GFP_KERNEL);
- if (!new_mca)
+ /* speculative alloc new mca */
+ mca = kzalloc(sizeof(*mca), GFP_KERNEL);
+ if (!mca)
return -ENOMEM;
spin_lock_bh(&rxe->mcg_lock);
/* re-check to see if someone else just attached qp */
- list_for_each_entry(mca, &mcg->qp_list, qp_list) {
+ list_for_each_entry(tmp, &mcg->qp_list, qp_list) {
if (mca->qp == qp) {
- kfree(new_mca);
+ kfree(mca);
err = 0;
- goto out;
+ goto done;
}
}
- mca = new_mca;
- if (atomic_read(&mcg->qp_num) >= rxe->attr.max_mcast_qp_attach) {
- err = -ENOMEM;
- goto out;
- }
+ err = __rxe_init_mca(qp, mcg, mca);
+ if (err)
+ kfree(mca);
+done:
+ spin_unlock_bh(&rxe->mcg_lock);
- atomic_inc(&mcg->qp_num);
- mca->qp = qp;
- atomic_inc(&qp->mcg_num);
+ return err;
+}
- list_add_tail(&mca->qp_list, &mcg->qp_list);
+/**
+ * __rxe_cleanup_mca - cleanup mca object holding lock
+ * @mca: mca object
+ * @mcg: mcg object
+ *
+ * Context: caller must hold a reference to mcg and rxe->mcg_lock
+ */
+static void __rxe_cleanup_mca(struct rxe_mca *mca, struct rxe_mcg *mcg)
+{
+ list_del(&mca->qp_list);
- err = 0;
-out:
- spin_unlock_bh(&rxe->mcg_lock);
- return err;
+ rxe_drop_ref(mca->qp);
+
+ atomic_dec(&mcg->qp_num);
+ atomic_dec(&mcg->rxe->mcg_attach);
+ atomic_dec(&mca->qp->mcg_num);
}
-static int rxe_mcast_drop_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
- union ib_gid *mgid)
+/**
+ * rxe_detach_mcg - detach qp from mcg
+ * @mcg: mcg object
+ * @qp: qp object
+ *
+ * Returns: 0 on success else an error if qp is not attached.
+ */
+static int rxe_detach_mcg(struct rxe_mcg *mcg, struct rxe_qp *qp)
{
- struct rxe_mcg *mcg;
+ struct rxe_dev *rxe = mcg->rxe;
struct rxe_mca *mca, *tmp;
- mcg = rxe_lookup_mcg(rxe, mgid);
- if (!mcg)
- goto err1;
-
spin_lock_bh(&rxe->mcg_lock);
-
list_for_each_entry_safe(mca, tmp, &mcg->qp_list, qp_list) {
if (mca->qp == qp) {
- list_del(&mca->qp_list);
- if (atomic_dec_return(&mcg->qp_num) <= 0)
+ __rxe_cleanup_mca(mca, mcg);
+ if (atomic_read(&mcg->qp_num) <= 0)
__rxe_destroy_mcg(mcg);
- atomic_dec(&qp->mcg_num);
-
spin_unlock_bh(&rxe->mcg_lock);
- kref_put(&mcg->ref_cnt, rxe_cleanup_mcg);
kfree(mca);
return 0;
}
}
-
spin_unlock_bh(&rxe->mcg_lock);
- kref_put(&mcg->ref_cnt, rxe_cleanup_mcg);
-err1:
+
return -EINVAL;
}
+/**
+ * rxe_attach_mcast - attach qp to multicast group (see IBA-11.3.1)
+ * @ibqp: (IB) qp object
+ * @mgid: multicast IP address
+ * @mlid: multicast LID, ignored for RoCEv2 (see IBA-A17.5.6)
+ *
+ * Returns: 0 on success else an errno
+ */
int rxe_attach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
{
int err;
@@ -374,8 +437,11 @@ int rxe_attach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
if (err)
return err;
- err = rxe_mcast_add_grp_elem(rxe, qp, mcg);
+ err = rxe_attach_mcg(mcg, qp);
+ /* this can happen if we failed to attach a first qp to mcg
+ * go ahead and destroy mcg
+ */
if (atomic_read(&mcg->qp_num) == 0)
rxe_destroy_mcg(mcg);
@@ -383,12 +449,29 @@ int rxe_attach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
return err;
}
+/**
+ * rxe_detach_mcast - detach qp from multicast group (see IBA-11.3.2)
+ * @ibqp: address of (IB) qp object
+ * @mgid: multicast IP address
+ * @mlid: multicast LID, ignored for RoCEv2 (see IBA-A17.5.6)
+ *
+ * Returns: 0 on success else an errno
+ */
int rxe_detach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
{
struct rxe_dev *rxe = to_rdev(ibqp->device);
struct rxe_qp *qp = to_rqp(ibqp);
+ struct rxe_mcg *mcg;
+ int err;
- return rxe_mcast_drop_grp_elem(rxe, qp, mgid);
+ mcg = rxe_lookup_mcg(rxe, mgid);
+ if (!mcg)
+ return -EINVAL;
+
+ err = rxe_detach_mcg(mcg, qp);
+ kref_put(&mcg->ref_cnt, rxe_cleanup_mcg);
+
+ return err;
}
/**
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h
index 72a913a8e0cb..716f11ec80fe 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -401,6 +401,7 @@ struct rxe_dev {
spinlock_t mcg_lock; /* guard multicast groups */
struct rb_root mcg_tree;
atomic_t mcg_num;
+ atomic_t mcg_attach;
unsigned int mcg_next;
spinlock_t pending_lock; /* guard pending_mmaps */
--
2.32.0
