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SRP fail-over faster

PATCH In review Vu Pham 2 participants 3 messages Oct 12, 2009 – Oct 14, 2009 2 messages not in the archive

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Vu Pham

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#0 lore raw

PATCH 1/4 SRP fail-over faster

Recreating qp, cq at reconnect instead of re-use them. We need this so that we don't have to wait on disconnect connection

---
 drivers/infiniband/ulp/srp/ib_srp.c |   22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)
drivers/infiniband/ulp/srp/ib_srp.c +11 -11
Index: ofed_kernel/drivers/infiniband/ulp/srp/ib_srp.c
===================================================================
@@ -537,10 +537,10 @@ static void srp_reset_req(struct srp_tar
 
 static int srp_reconnect_target(struct srp_target_port *target)
 {
-	struct ib_qp_attr qp_attr;
 	struct srp_request *req, *tmp;
-	struct ib_wc wc;
 	int ret;
+	struct ib_cq *old_cq;
+	struct ib_qp *old_qp;
 
 	spin_lock_irq(target->scsi_host->host_lock);
 	if (target->state != SRP_TARGET_LIVE) {
@@ -559,17 +559,17 @@ static int srp_reconnect_target(struct s
 	if (ret)
 		goto err;
 
-	qp_attr.qp_state = IB_QPS_RESET;
-	ret = ib_modify_qp(target->qp, &qp_attr, IB_QP_STATE);
-	if (ret)
-		goto err;
-
-	ret = srp_init_qp(target, target->qp);
-	if (ret)
+	old_qp = target->qp;
+	old_cq = target->cq;
+	ret = srp_create_target_ib(target);
+	if (ret) {
+		target->qp = old_qp;
+		target->cq = old_cq;
 		goto err;
+	}
 
-	while (ib_poll_cq(target->cq, 1, &wc) > 0)
-		; /* nothing */
+	ib_destroy_qp(old_qp);
+	ib_destroy_cq(old_cq);
 
 	spin_lock_irq(target->scsi_host->host_lock);
 	list_for_each_entry_safe(req, tmp, &target->req_queue, list)

A message that is not in the archive (sent off-list or not yet received): 4AD3B433.7040803-VPRAkNaXOzVWk0Htik3J/[email protected]

#2 lore raw

One meta comment: when sending a series of 4 patches, please choose a descriptive subject for each one. We don't want the same headline in the kernel log for all 4 patches.

drivers/infiniband/ulp/srp/ib_srp.c static int srp_reconnect_target(struct s · line 564

Quoted 10 lines
drivers/infiniband/ulp/srp/ib_srp.c +3 -7
-	qp_attr.qp_state = IB_QPS_RESET;
-	ret = ib_modify_qp(target->qp, &qp_attr, IB_QP_STATE);
-	if (ret)
-		goto err;
-
-	ret = srp_init_qp(target, target->qp);
-	if (ret)
+	old_qp = target->qp;
+	old_cq = target->cq;
+	ret = srp_create_target_ib(target);

I don't understand why this is any faster? Is creating a new QP really any different from modifying an old QP to reset state?
--
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A message that is not in the archive (sent off-list or not yet received): [email protected]

author
#4 lore raw
Quoted 5 lines · Roland Dreier

One meta comment: when sending a series of 4 patches, please choose a descriptive subject for each one. We don't want the same headline in the kernel log for all 4 patches.

I'll remember next time

Quoted 5 lines
Quoted 5 lines
drivers/infiniband/ulp/srp/ib_srp.c +0 -5
-	qp_attr.qp_state = IB_QPS_RESET;
-	ret = ib_modify_qp(target->qp, &qp_attr, IB_QP_STATE);
-	if (ret)
-		goto err;
-
Quoted 9 lines

drivers/infiniband/ulp/srp/ib_srp.c static int srp_reconnect_target(struct s · line 564

Quoted 5 lines
drivers/infiniband/ulp/srp/ib_srp.c +3 -2
-	ret = srp_init_qp(target, target->qp);
-	if (ret)
+	old_qp = target->qp;
+	old_cq = target->cq;
+	ret = srp_create_target_ib(target);

I don't understand why this is any faster? Is creating a new QP really any different from modifying an old QP to reset state?

It is not; it is needed for patch 2/4 disconnect without wait and it is faster that way --
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