IB/srp: destroy and recreate QP and CQs when reconnecting

HW QP FATAL errors persist over a reset operation, but we can recover
from that by recreating the QP and associated CQs for each connection.
Creating a new QP/CQ also completely forecloses any possibility of
getting stale completions or packets on the new connection.

Signed-off-by: Ishai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>

[ updated to current code from OFED, cleaned up commit message ]

Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 35 insertions, 31 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 95590a38e88..85771eba9c8 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -222,27 +222,29 @@ static int srp_new_cm_id(struct srp_target_port *target)
 static int srp_create_target_ib(struct srp_target_port *target)
 {
         struct ib_qp_init_attr *init_attr;
+        struct ib_cq *recv_cq, *send_cq;
+        struct ib_qp *qp;
         int ret;
 
         init_attr = kzalloc(sizeof *init_attr, GFP_KERNEL);
         if (!init_attr)
                 return -ENOMEM;
 
-        target->recv_cq = ib_create_cq(target->srp_host->srp_dev->dev,
-                                       srp_recv_completion, NULL, target, SRP_RQ_SIZE, 0);
-        if (IS_ERR(target->recv_cq)) {
-                ret = PTR_ERR(target->recv_cq);
+        recv_cq = ib_create_cq(target->srp_host->srp_dev->dev,
+                               srp_recv_completion, NULL, target, SRP_RQ_SIZE, 0);
+        if (IS_ERR(recv_cq)) {
+                ret = PTR_ERR(recv_cq);
                 goto err;
         }
 
-        target->send_cq = ib_create_cq(target->srp_host->srp_dev->dev,
-                                       srp_send_completion, NULL, target, SRP_SQ_SIZE, 0);
-        if (IS_ERR(target->send_cq)) {
-                ret = PTR_ERR(target->send_cq);
+        send_cq = ib_create_cq(target->srp_host->srp_dev->dev,
+                               srp_send_completion, NULL, target, SRP_SQ_SIZE, 0);
+        if (IS_ERR(send_cq)) {
+                ret = PTR_ERR(send_cq);
                 goto err_recv_cq;
         }
 
-        ib_req_notify_cq(target->recv_cq, IB_CQ_NEXT_COMP);
+        ib_req_notify_cq(recv_cq, IB_CQ_NEXT_COMP);
 
         init_attr->event_handler       = srp_qp_event;
         init_attr->cap.max_send_wr     = SRP_SQ_SIZE;
@@ -251,30 +253,41 @@ static int srp_create_target_ib(struct srp_target_port *target)
         init_attr->cap.max_send_sge    = 1;
         init_attr->sq_sig_type         = IB_SIGNAL_ALL_WR;
         init_attr->qp_type             = IB_QPT_RC;
-        init_attr->send_cq             = target->send_cq;
-        init_attr->recv_cq             = target->recv_cq;
+        init_attr->send_cq             = send_cq;
+        init_attr->recv_cq             = recv_cq;
 
-        target->qp = ib_create_qp(target->srp_host->srp_dev->pd, init_attr);
-        if (IS_ERR(target->qp)) {
-                ret = PTR_ERR(target->qp);
+        qp = ib_create_qp(target->srp_host->srp_dev->pd, init_attr);
+        if (IS_ERR(qp)) {
+                ret = PTR_ERR(qp);
                 goto err_send_cq;
         }
 
-        ret = srp_init_qp(target, target->qp);
+        ret = srp_init_qp(target, qp);
         if (ret)
                 goto err_qp;
 
+        if (target->qp)
+                ib_destroy_qp(target->qp);
+        if (target->recv_cq)
+                ib_destroy_cq(target->recv_cq);
+        if (target->send_cq)
+                ib_destroy_cq(target->send_cq);
+
+        target->qp = qp;
+        target->recv_cq = recv_cq;
+        target->send_cq = send_cq;
+
         kfree(init_attr);
         return 0;
 
 err_qp:
-        ib_destroy_qp(target->qp);
+        ib_destroy_qp(qp);
 
 err_send_cq:
-        ib_destroy_cq(target->send_cq);
+        ib_destroy_cq(send_cq);
 
 err_recv_cq:
-        ib_destroy_cq(target->recv_cq);
+        ib_destroy_cq(recv_cq);
 
 err:
         kfree(init_attr);
@@ -289,6 +302,9 @@ static void srp_free_target_ib(struct srp_target_port *target)
         ib_destroy_cq(target->send_cq);
         ib_destroy_cq(target->recv_cq);
 
+        target->qp = NULL;
+        target->send_cq = target->recv_cq = NULL;
+
         for (i = 0; i < SRP_RQ_SIZE; ++i)
                 srp_free_iu(target->srp_host, target->rx_ring[i]);
         for (i = 0; i < SRP_SQ_SIZE; ++i)
@@ -678,8 +694,6 @@ static void srp_reset_req(struct srp_target_port *target, struct srp_request *re
 static int srp_reconnect_target(struct srp_target_port *target)
 {
         struct Scsi_Host *shost = target->scsi_host;
-        struct ib_qp_attr qp_attr;
-        struct ib_wc wc;
         int i, ret;
 
         if (target->state != SRP_TARGET_LIVE)
@@ -696,20 +710,10 @@ static int srp_reconnect_target(struct srp_target_port *target)
         if (ret)
                 goto unblock;
 
-        qp_attr.qp_state = IB_QPS_RESET;
-        ret = ib_modify_qp(target->qp, &qp_attr, IB_QP_STATE);
-        if (ret)
-                goto unblock;
-
-        ret = srp_init_qp(target, target->qp);
+        ret = srp_create_target_ib(target);
         if (ret)
                 goto unblock;
 
-        while (ib_poll_cq(target->recv_cq, 1, &wc) > 0)
-                ; /* nothing */
-        while (ib_poll_cq(target->send_cq, 1, &wc) > 0)
-                ; /* nothing */
-
         for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
                 struct srp_request *req = &target->req_ring[i];
                 if (req->scmnd)