IB/qib: Decode path MTU optimization

Store both the encoded and decoded MTU in the QP structure as a minor
optimization for UC/RC receive routines.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

4 files changed, 9 insertions, 6 deletions

diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index e16751f8639e..9d094f910360 100644
--- a/drivers/infiniband/hw/qib/qib_qp.c
+++ b/drivers/infiniband/hw/qib/qib_qp.c
@@ -765,8 +765,10 @@ int qib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
                 }
         }
 
-        if (attr_mask & IB_QP_PATH_MTU)
+        if (attr_mask & IB_QP_PATH_MTU) {
                 qp->path_mtu = pmtu;
+                qp->pmtu = ib_mtu_enum_to_int(pmtu);
+        }
 
         if (attr_mask & IB_QP_RETRY_CNT) {
                 qp->s_retry_cnt = attr->retry_cnt;
diff --git a/drivers/infiniband/hw/qib/qib_rc.c b/drivers/infiniband/hw/qib/qib_rc.c
index 5c1c49b299f1..5d77cb8aa052 100644
--- a/drivers/infiniband/hw/qib/qib_rc.c
+++ b/drivers/infiniband/hw/qib/qib_rc.c
@@ -239,7 +239,7 @@ int qib_make_rc_req(struct qib_qp *qp)
         u32 len;
         u32 bth0;
         u32 bth2;
-        u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+        u32 pmtu = qp->pmtu;
         char newreq;
         unsigned long flags;
         int ret = 0;
@@ -1732,7 +1732,7 @@ static int qib_rc_rcv_error(struct qib_other_headers *ohdr,
                  * same request.
                  */
                 offset = ((psn - e->psn) & QIB_PSN_MASK) *
-                        ib_mtu_enum_to_int(qp->path_mtu);
+                        qp->pmtu;
                 len = be32_to_cpu(reth->length);
                 if (unlikely(offset + len != e->rdma_sge.sge_length))
                         goto unlock_done;
@@ -1876,7 +1876,7 @@ void qib_rc_rcv(struct qib_ctxtdata *rcd, struct qib_ib_header *hdr,
         u32 psn;
         u32 pad;
         struct ib_wc wc;
-        u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+        u32 pmtu = qp->pmtu;
         int diff;
         struct ib_reth *reth;
         unsigned long flags;
diff --git a/drivers/infiniband/hw/qib/qib_uc.c b/drivers/infiniband/hw/qib/qib_uc.c
index d31f33a99887..9a4630f8276f 100644
--- a/drivers/infiniband/hw/qib/qib_uc.c
+++ b/drivers/infiniband/hw/qib/qib_uc.c
@@ -51,7 +51,7 @@ int qib_make_uc_req(struct qib_qp *qp)
         u32 hwords;
         u32 bth0;
         u32 len;
-        u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+        u32 pmtu = qp->pmtu;
         int ret = 0;
 
         spin_lock_irqsave(&qp->s_lock, flags);
@@ -249,7 +249,7 @@ void qib_uc_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
         u32 psn;
         u32 pad;
         struct ib_wc wc;
-        u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+        u32 pmtu = qp->pmtu;
         struct ib_reth *reth;
         int ret;
 
diff --git a/drivers/infiniband/hw/qib/qib_verbs.h b/drivers/infiniband/hw/qib/qib_verbs.h
index 95e5b47223b3..ec3711f743c5 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.h
+++ b/drivers/infiniband/hw/qib/qib_verbs.h
@@ -485,6 +485,7 @@ struct qib_qp {
         u8 alt_timeout;         /* Alternate path timeout for this QP */
         u8 port_num;
         enum ib_mtu path_mtu;
+        u32 pmtu;               /* decoded from path_mtu */
         u32 remote_qpn;
         u32 qkey;               /* QKEY for this QP (for UD or RD) */
         u32 s_size;             /* send work queue size */