RDMA: Hold the sgid_attr inside the struct ib_ah/qp

If the AH has a GRH then hold a reference to the sgid_attr inside the
common struct.

If the QP is modified with an AV that includes a GRH then also hold a
reference to the sgid_attr inside the common struct.

This informs the cache that the sgid_index is in-use so long as the AH or
QP using it exists.

This also means that all drivers can access the sgid_attr directly from
the ah_attr instead of querying the cache during their UD post-send paths.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index 2c7129c..b0ad739 100644 (file)
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -459,6 +459,19 @@ static void rdma_unfill_sgid_attr(struct rdma_ah_attr *ah_attr,
        rdma_destroy_ah_attr(ah_attr);
 }
 
+static const struct ib_gid_attr *
+rdma_update_sgid_attr(struct rdma_ah_attr *ah_attr,
+                     const struct ib_gid_attr *old_attr)
+{
+       if (old_attr)
+               rdma_put_gid_attr(old_attr);
+       if (ah_attr->ah_flags & IB_AH_GRH) {
+               rdma_hold_gid_attr(ah_attr->grh.sgid_attr);
+               return ah_attr->grh.sgid_attr;
+       }
+       return NULL;
+}
+
 static struct ib_ah *_rdma_create_ah(struct ib_pd *pd,
                                     struct rdma_ah_attr *ah_attr,
                                     struct ib_udata *udata)
@@ -472,6 +485,8 @@ static struct ib_ah *_rdma_create_ah(struct ib_pd *pd,
                ah->pd      = pd;
                ah->uobject = NULL;
                ah->type    = ah_attr->type;
+               ah->sgid_attr = rdma_update_sgid_attr(ah_attr, NULL);
+
                atomic_inc(&pd->usecnt);
        }
 
@@ -871,6 +886,7 @@ int rdma_modify_ah(struct ib_ah *ah, struct rdma_ah_attr *ah_attr)
                ah->device->modify_ah(ah, ah_attr) :
                -EOPNOTSUPP;
 
+       ah->sgid_attr = rdma_update_sgid_attr(ah_attr, ah->sgid_attr);
        rdma_unfill_sgid_attr(ah_attr, old_sgid_attr);
        return ret;
 }
@@ -888,13 +904,17 @@ EXPORT_SYMBOL(rdma_query_ah);
 
 int rdma_destroy_ah(struct ib_ah *ah)
 {
+       const struct ib_gid_attr *sgid_attr = ah->sgid_attr;
        struct ib_pd *pd;
        int ret;
 
        pd = ah->pd;
        ret = ah->device->destroy_ah(ah);
-       if (!ret)
+       if (!ret) {
                atomic_dec(&pd->usecnt);
+               if (sgid_attr)
+                       rdma_put_gid_attr(sgid_attr);
+       }
 
        return ret;
 }
@@ -1573,6 +1593,13 @@ static int _ib_modify_qp(struct ib_qp *qp, struct ib_qp_attr *attr,
                        return ret;
        }
        if (attr_mask & IB_QP_ALT_PATH) {
+               /*
+                * FIXME: This does not track the migration state, so if the
+                * user loads a new alternate path after the HW has migrated
+                * from primary->alternate we will keep the wrong
+                * references. This is OK for IB because the reference
+                * counting does not serve any functional purpose.
+                */
                ret = rdma_fill_sgid_attr(qp->device, &attr->alt_ah_attr,
                                          &old_sgid_attr_alt_av);
                if (ret)
@@ -1606,8 +1633,17 @@ static int _ib_modify_qp(struct ib_qp *qp, struct ib_qp_attr *attr,
        }
 
        ret = ib_security_modify_qp(qp, attr, attr_mask, udata);
-       if (!ret && (attr_mask & IB_QP_PORT))
+       if (ret)
+               goto out;
+
+       if (attr_mask & IB_QP_PORT)
                qp->port = attr->port_num;
+       if (attr_mask & IB_QP_AV)
+               qp->av_sgid_attr =
+                       rdma_update_sgid_attr(&attr->ah_attr, qp->av_sgid_attr);
+       if (attr_mask & IB_QP_ALT_PATH)
+               qp->alt_path_sgid_attr = rdma_update_sgid_attr(
+                       &attr->alt_ah_attr, qp->alt_path_sgid_attr);
 
 out:
        if (attr_mask & IB_QP_ALT_PATH)
@@ -1765,6 +1801,8 @@ static int __ib_destroy_shared_qp(struct ib_qp *qp)
 
 int ib_destroy_qp(struct ib_qp *qp)
 {
+       const struct ib_gid_attr *alt_path_sgid_attr = qp->alt_path_sgid_attr;
+       const struct ib_gid_attr *av_sgid_attr = qp->av_sgid_attr;
        struct ib_pd *pd;
        struct ib_cq *scq, *rcq;
        struct ib_srq *srq;
@@ -1795,6 +1833,10 @@ int ib_destroy_qp(struct ib_qp *qp)
        rdma_restrack_del(&qp->res);
        ret = qp->device->destroy_qp(qp);
        if (!ret) {
+               if (alt_path_sgid_attr)
+                       rdma_put_gid_attr(alt_path_sgid_attr);
+               if (av_sgid_attr)
+                       rdma_put_gid_attr(av_sgid_attr);
                if (pd)
                        atomic_dec(&pd->usecnt);
                if (scq)

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 65f467d..0232c0f 100644 (file)
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1580,6 +1580,7 @@ struct ib_ah {
        struct ib_device        *device;
        struct ib_pd            *pd;
        struct ib_uobject       *uobject;
+       const struct ib_gid_attr *sgid_attr;
        enum rdma_ah_attr_type  type;
 };
 
@@ -1778,6 +1779,9 @@ struct ib_qp {
        struct ib_uobject      *uobject;
        void                  (*event_handler)(struct ib_event *, void *);
        void                   *qp_context;
+       /* sgid_attrs associated with the AV's */
+       const struct ib_gid_attr *av_sgid_attr;
+       const struct ib_gid_attr *alt_path_sgid_attr;
        u32                     qp_num;
        u32                     max_write_sge;
        u32                     max_read_sge;