[git patch review 1/3] [IB] srp: increase max_luns

[git patch review 1/3] [IB] srp: increase max_luns

[Roland Dreier]

Increase SRP max_luns to 512 to match the kernel's default, since SRP
storage targets can have lots of LUNs and the SRP initiator itself
doesn't have any particular limit.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

---

 drivers/infiniband/ulp/srp/ib_srp.c |    2 ++
 drivers/infiniband/ulp/srp/ib_srp.h |    1 +
 2 files changed, 3 insertions(+), 0 deletions(-)

applies-to: 84a581820bff0fa9830f18138da02d929e4edcb9
5f068992a1bccda5574b4f6d33458ef806686d7f
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 321a3a1..a364530 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1417,6 +1417,8 @@ static ssize_t srp_create_target(struct 
 	if (!target_host)
 		return -ENOMEM;
 
+	target_host->max_lun = SRP_MAX_LUN;
+
 	target = host_to_target(target_host);
 	memset(target, 0, sizeof *target);
 
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 4fec28a..b564f18 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -54,6 +54,7 @@ enum {
 	SRP_PORT_REDIRECT	= 1,
 	SRP_DLID_REDIRECT	= 2,
 
+	SRP_MAX_LUN		= 512,
 	SRP_MAX_IU_LEN		= 256,
 
 	SRP_RQ_SHIFT    	= 6,
---
0.99.9g

[git patch review 2/3] [IB] srp: don't post receive if no send buf available

[Roland Dreier]

Have __srp_get_tx_iu() fail if the target port's request limit will
not allow the initiator to post a send.  This avoids continuing on and
posting a receive, and then failing to post a corresponding send.  If
that happens, then the initiator will end up with an extra receive
posted, and if this happens to much, the receive queue will overflow.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

---

 drivers/infiniband/ulp/srp/ib_srp.c |   15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)

applies-to: a5f8266c59f39f0a1f3dc3d71a00da7276ac1a80
47f2bce9021b4974ed33b072ebb8348c8145c946
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index a364530..ee9fe22 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -802,13 +802,21 @@ static int srp_post_recv(struct srp_targ
 
 /*
  * Must be called with target->scsi_host->host_lock held to protect
- * req_lim and tx_head.
+ * req_lim and tx_head.  Lock cannot be dropped between call here and
+ * call to __srp_post_send().
  */
 static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target)
 {
 	if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
 		return NULL;
 
+	if (unlikely(target->req_lim < 1)) {
+		if (printk_ratelimit())
+			printk(KERN_DEBUG PFX "Target has req_lim %d\n",
+			       target->req_lim);
+		return NULL;
+	}
+
 	return target->tx_ring[target->tx_head & SRP_SQ_SIZE];
 }
 
@@ -823,11 +831,6 @@ static int __srp_post_send(struct srp_ta
 	struct ib_send_wr wr, *bad_wr;
 	int ret = 0;
 
-	if (target->req_lim < 1) {
-		printk(KERN_ERR PFX "Target has req_lim %d\n", target->req_lim);
-		return -EAGAIN;
-	}
-
 	list.addr   = iu->dma;
 	list.length = len;
 	list.lkey   = target->srp_host->mr->lkey;
---
0.99.9g

[git patch review 3/3] [IB] mthca: don't disable RDMA writes if no responder resources

[Roland Dreier]

Responder resources are only required to handle RDMA reads and atomic
operations, not RDMA writes.  So the driver should allow RDMA writes
even if responder resources are set to 0.  This is especially
important for the UC transport -- with the old code, it was impossible
to enable RDMA writes for UC QPs.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

---

 drivers/infiniband/hw/mthca/mthca_qp.c |   27 ++++++++++++---------------
 1 files changed, 12 insertions(+), 15 deletions(-)

applies-to: 2d17f2cdc77646d07cb2a598e3d2bcbdf94675ad
cbc5b2bb9e226c2b2b981836d2289912e2ef3c1c
diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c
index 760c418..5899f0c 100644
--- a/drivers/infiniband/hw/mthca/mthca_qp.c
+++ b/drivers/infiniband/hw/mthca/mthca_qp.c
@@ -730,15 +730,16 @@ int mthca_modify_qp(struct ib_qp *ibqp, 
 	}
 
 	if (attr_mask & IB_QP_ACCESS_FLAGS) {
+		qp_context->params2 |=
+			cpu_to_be32(attr->qp_access_flags & IB_ACCESS_REMOTE_WRITE ?
+				    MTHCA_QP_BIT_RWE : 0);
+
 		/*
-		 * Only enable RDMA/atomics if we have responder
-		 * resources set to a non-zero value.
+		 * Only enable RDMA reads and atomics if we have
+		 * responder resources set to a non-zero value.
 		 */
 		if (qp->resp_depth) {
 			qp_context->params2 |=
-				cpu_to_be32(attr->qp_access_flags & IB_ACCESS_REMOTE_WRITE ?
-					    MTHCA_QP_BIT_RWE : 0);
-			qp_context->params2 |=
 				cpu_to_be32(attr->qp_access_flags & IB_ACCESS_REMOTE_READ ?
 					    MTHCA_QP_BIT_RRE : 0);
 			qp_context->params2 |=
@@ -759,31 +760,27 @@ int mthca_modify_qp(struct ib_qp *ibqp, 
 		if (qp->resp_depth && !attr->max_dest_rd_atomic) {
 			/*
 			 * Lowering our responder resources to zero.
-			 * Turn off RDMA/atomics as responder.
-			 * (RWE/RRE/RAE in params2 already zero)
+			 * Turn off reads RDMA and atomics as responder.
+			 * (RRE/RAE in params2 already zero)
 			 */
-			qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RWE |
-								MTHCA_QP_OPTPAR_RRE |
+			qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RRE |
 								MTHCA_QP_OPTPAR_RAE);
 		}
 
 		if (!qp->resp_depth && attr->max_dest_rd_atomic) {
 			/*
 			 * Increasing our responder resources from
-			 * zero.  Turn on RDMA/atomics as appropriate.
+			 * zero.  Turn on RDMA reads and atomics as
+			 * appropriate.
 			 */
 			qp_context->params2 |=
-				cpu_to_be32(qp->atomic_rd_en & IB_ACCESS_REMOTE_WRITE ?
-					    MTHCA_QP_BIT_RWE : 0);
-			qp_context->params2 |=
 				cpu_to_be32(qp->atomic_rd_en & IB_ACCESS_REMOTE_READ ?
 					    MTHCA_QP_BIT_RRE : 0);
 			qp_context->params2 |=
 				cpu_to_be32(qp->atomic_rd_en & IB_ACCESS_REMOTE_ATOMIC ?
 					    MTHCA_QP_BIT_RAE : 0);
 
-			qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RWE |
-								MTHCA_QP_OPTPAR_RRE |
+			qp_param->opt_param_mask |= cpu_to_be32(MTHCA_QP_OPTPAR_RRE |
 								MTHCA_QP_OPTPAR_RAE);
 		}
 
---
0.99.9g