[PATCH v2 0/8] SRP patches for kernel v4.15

[PATCH v2 0/8] SRP patches for kernel v4.15

[Bart Van Assche]

Hello Doug,

This patch series includes several the SRP initiator and target patches I came
up with during the past months. The initiator patches are independent of the
target patches. Please consider these patches for kernel v4.15.

Thanks,

Bart.

Changes compared to v1:
- In patch "IB/srpt: Change default behavior from using SRQ to not using SRQ",
  changed a kernel module parameter into a configfs attribute.
- Added a "Fixes" tag to patch "IB/srp: Avoid that a cable pull can trigger a
  kernel crash".
- Added an eighth patch at the start of this patch series.
- Added Reviewed-by tags for the patches that got a positive review.

Bart Van Assche (8):
  IB/srpt: Do not accept invalid initiator port names
  IB/srpt: Limit the send and receive queue sizes to what the HCA
    supports
  IB/srpt: Cache global L_Key
  IB/srpt: Change default behavior from using SRQ to using RC
  IB/srp: Avoid that a cable pull can trigger a kernel crash
  IB/srp: Remove second argument of srp_destroy_qp()
  IB/srp: Cache global rkey
  IB/srp: Make CM timeout dependent on subnet timeout

 drivers/infiniband/ulp/srp/ib_srp.c   |  88 +++++++++++------
 drivers/infiniband/ulp/srp/ib_srp.h   |   3 +-
 drivers/infiniband/ulp/srpt/ib_srpt.c | 176 +++++++++++++++++++++++++---------
 drivers/infiniband/ulp/srpt/ib_srpt.h |   9 +-
 4 files changed, 201 insertions(+), 75 deletions(-)

-- 
2.14.2

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[PATCH v2 1/8] IB/srpt: Do not accept invalid initiator port names

[Bart Van Assche]

Make srpt_parse_i_port_id() return a negative value if hex2bin()
fails.

Fixes: commit a42d985bd5b2 ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
Signed-off-by: Bart Van Assche <bart.vanassche-Sjgp3cTcYWE@public.gmane.org>
Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 9e8e9220f816..95178b4e3565 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -2777,7 +2777,7 @@ static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
 {
 	const char *p;
 	unsigned len, count, leading_zero_bytes;
-	int ret, rc;
+	int ret;
 
 	p = name;
 	if (strncasecmp(p, "0x", 2) == 0)
@@ -2789,10 +2789,9 @@ static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
 	count = min(len / 2, 16U);
 	leading_zero_bytes = 16 - count;
 	memset(i_port_id, 0, leading_zero_bytes);
-	rc = hex2bin(i_port_id + leading_zero_bytes, p, count);
-	if (rc < 0)
-		pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", rc);
-	ret = 0;
+	ret = hex2bin(i_port_id + leading_zero_bytes, p, count);
+	if (ret < 0)
+		pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", ret);
 out:
 	return ret;
 }
-- 
2.14.2

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[PATCH v2 1/8] IB/srpt: Do not accept invalid initiator port names

[Bart Van Assche]

Make srpt_parse_i_port_id() return a negative value if hex2bin()
fails.

Fixes: commit a42d985bd5b2 ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: <stable@vger.kernel.org>
---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 9e8e9220f816..95178b4e3565 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -2777,7 +2777,7 @@ static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
 {
 	const char *p;
 	unsigned len, count, leading_zero_bytes;
-	int ret, rc;
+	int ret;
 
 	p = name;
 	if (strncasecmp(p, "0x", 2) == 0)
@@ -2789,10 +2789,9 @@ static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
 	count = min(len / 2, 16U);
 	leading_zero_bytes = 16 - count;
 	memset(i_port_id, 0, leading_zero_bytes);
-	rc = hex2bin(i_port_id + leading_zero_bytes, p, count);
-	if (rc < 0)
-		pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", rc);
-	ret = 0;
+	ret = hex2bin(i_port_id + leading_zero_bytes, p, count);
+	if (ret < 0)
+		pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", ret);
 out:
 	return ret;
 }
-- 
2.14.2

[PATCH v2 2/8] IB/srpt: Limit the send and receive queue sizes to what the HCA supports

[Bart Van Assche]

Additionally, correct the comment about ch->rq_size.

Signed-off-by: Bart Van Assche <bart.vanassche-Sjgp3cTcYWE@public.gmane.org>
Reviewed-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 95178b4e3565..76370e39857d 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1650,7 +1650,7 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 	 * both both, as RDMA contexts will also post completions for the
 	 * RDMA READ case.
 	 */
-	qp_init->cap.max_send_wr = srp_sq_size / 2;
+	qp_init->cap.max_send_wr = min(srp_sq_size / 2, attrs->max_qp_wr + 0U);
 	qp_init->cap.max_rdma_ctxs = srp_sq_size / 2;
 	qp_init->cap.max_send_sge = min(attrs->max_sge, SRPT_MAX_SG_PER_WQE);
 	qp_init->port_num = ch->sport->port;
@@ -1953,10 +1953,11 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
 	ch->cm_id = cm_id;
 	cm_id->context = ch;
 	/*
-	 * Avoid QUEUE_FULL conditions by limiting the number of buffers used
-	 * for the SRP protocol to the command queue size.
+	 * ch->rq_size should be at least as large as the initiator queue
+	 * depth to avoid that the initiator driver has to report QUEUE_FULL
+	 * to the SCSI mid-layer.
 	 */
-	ch->rq_size = SRPT_RQ_SIZE;
+	ch->rq_size = min(SRPT_RQ_SIZE, sdev->device->attrs.max_qp_wr);
 	spin_lock_init(&ch->spinlock);
 	ch->state = CH_CONNECTING;
 	INIT_LIST_HEAD(&ch->cmd_wait_list);
-- 
2.14.2

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[PATCH v2 3/8] IB/srpt: Cache global L_Key

[Bart Van Assche]

This patch is a micro-optimization for the hot path.

Signed-off-by: Bart Van Assche <bart.vanassche-Sjgp3cTcYWE@public.gmane.org>
---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 6 ++++--
 drivers/infiniband/ulp/srpt/ib_srpt.h | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 76370e39857d..6cf95ad870cc 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -766,7 +766,7 @@ static int srpt_post_recv(struct srpt_device *sdev,
 	BUG_ON(!sdev);
 	list.addr = ioctx->ioctx.dma;
 	list.length = srp_max_req_size;
-	list.lkey = sdev->pd->local_dma_lkey;
+	list.lkey = sdev->lkey;
 
 	ioctx->ioctx.cqe.done = srpt_recv_done;
 	wr.wr_cqe = &ioctx->ioctx.cqe;
@@ -2343,7 +2343,7 @@ static void srpt_queue_response(struct se_cmd *cmd)
 
 	sge.addr = ioctx->ioctx.dma;
 	sge.length = resp_len;
-	sge.lkey = sdev->pd->local_dma_lkey;
+	sge.lkey = sdev->lkey;
 
 	ioctx->ioctx.cqe.done = srpt_send_done;
 	send_wr.next = NULL;
@@ -2491,6 +2491,8 @@ static void srpt_add_one(struct ib_device *device)
 	if (IS_ERR(sdev->pd))
 		goto free_dev;
 
+	sdev->lkey = sdev->pd->local_dma_lkey;
+
 	sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
 
 	srq_attr.event_handler = srpt_srq_event;
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
index 1b817e51b84b..976e924d7400 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.h
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -343,7 +343,7 @@ struct srpt_port {
  * struct srpt_device - Information associated by SRPT with a single HCA.
  * @device:        Backpointer to the struct ib_device managed by the IB core.
  * @pd:            IB protection domain.
- * @mr:            L_Key (local key) with write access to all local memory.
+ * @lkey:          L_Key (local key) with write access to all local memory.
  * @srq:           Per-HCA SRQ (shared receive queue).
  * @cm_id:         Connection identifier.
  * @srq_size:      SRQ size.
@@ -358,6 +358,7 @@ struct srpt_port {
 struct srpt_device {
 	struct ib_device	*device;
 	struct ib_pd		*pd;
+	u32			lkey;
 	struct ib_srq		*srq;
 	struct ib_cm_id		*cm_id;
 	int			srq_size;
-- 
2.14.2

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[PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Bart Van Assche]

Although in the RC mode more resources are needed that mode has three
advantages over SRQ:
- It works with all RDMA adapters, even those that do not support
  SRQ.
- Posting WRs and polling WCs does not trigger lock contention
  because only one thread at a time accesses a WR or WC queue in
  non-SRQ mode.
- The end-to-end flow control mechanism is used.

>From the IB spec:

    C9-150.2.1: For QPs that are not associated with an SRQ, each HCA
    receive queue shall generate end-to-end flow control credits. If
    a QP is associated with an SRQ, the HCA receive queue shall not
    generate end-to-end flow control credits.

Add new configfs attributes that allow to configure which mode to use
(/sys/kernel/config/target/srpt/$GUID/$GUID/attrib/use_srq). Note:
only the attribute for port 1 is relevant on multi-port adapters.

Signed-off-by: Bart Van Assche <bart.vanassche-Sjgp3cTcYWE@public.gmane.org>
---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 152 ++++++++++++++++++++++++++--------
 drivers/infiniband/ulp/srpt/ib_srpt.h |   6 ++
 2 files changed, 123 insertions(+), 35 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 6cf95ad870cc..304855b9b537 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -295,6 +295,7 @@ static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
 {
 	struct srpt_device *sdev = sport->sdev;
 	struct ib_dm_ioc_profile *iocp;
+	int send_queue_depth;
 
 	iocp = (struct ib_dm_ioc_profile *)mad->data;
 
@@ -310,6 +311,12 @@ static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
 		return;
 	}
 
+	if (sdev->use_srq)
+		send_queue_depth = sdev->srq_size;
+	else
+		send_queue_depth = min(SRPT_RQ_SIZE,
+				       sdev->device->attrs.max_qp_wr);
+
 	memset(iocp, 0, sizeof(*iocp));
 	strcpy(iocp->id_string, SRPT_ID_STRING);
 	iocp->guid = cpu_to_be64(srpt_service_guid);
@@ -322,7 +329,7 @@ static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
 	iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
 	iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
 	iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
-	iocp->send_queue_depth = cpu_to_be16(sdev->srq_size);
+	iocp->send_queue_depth = cpu_to_be16(send_queue_depth);
 	iocp->rdma_read_depth = 4;
 	iocp->send_size = cpu_to_be32(srp_max_req_size);
 	iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
@@ -686,6 +693,9 @@ static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
 {
 	int i;
 
+	if (!ioctx_ring)
+		return;
+
 	for (i = 0; i < ring_size; ++i)
 		srpt_free_ioctx(sdev, ioctx_ring[i], dma_size, dir);
 	kfree(ioctx_ring);
@@ -757,7 +767,7 @@ static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
 /**
  * srpt_post_recv() - Post an IB receive request.
  */
-static int srpt_post_recv(struct srpt_device *sdev,
+static int srpt_post_recv(struct srpt_device *sdev, struct srpt_rdma_ch *ch,
 			  struct srpt_recv_ioctx *ioctx)
 {
 	struct ib_sge list;
@@ -774,7 +784,10 @@ static int srpt_post_recv(struct srpt_device *sdev,
 	wr.sg_list = &list;
 	wr.num_sge = 1;
 
-	return ib_post_srq_recv(sdev->srq, &wr, &bad_wr);
+	if (sdev->use_srq)
+		return ib_post_srq_recv(sdev->srq, &wr, &bad_wr);
+	else
+		return ib_post_recv(ch->qp, &wr, &bad_wr);
 }
 
 /**
@@ -1517,7 +1530,7 @@ static void srpt_handle_new_iu(struct srpt_rdma_ch *ch,
 		break;
 	}
 
-	srpt_post_recv(ch->sport->sdev, recv_ioctx);
+	srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
 	return;
 
 out_wait:
@@ -1616,7 +1629,7 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 	struct srpt_device *sdev = sport->sdev;
 	const struct ib_device_attr *attrs = &sdev->device->attrs;
 	u32 srp_sq_size = sport->port_attrib.srp_sq_size;
-	int ret;
+	int i, ret;
 
 	WARN_ON(ch->rq_size < 1);
 
@@ -1640,7 +1653,6 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 		= (void(*)(struct ib_event *, void*))srpt_qp_event;
 	qp_init->send_cq = ch->cq;
 	qp_init->recv_cq = ch->cq;
-	qp_init->srq = sdev->srq;
 	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
 	qp_init->qp_type = IB_QPT_RC;
 	/*
@@ -1654,6 +1666,12 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 	qp_init->cap.max_rdma_ctxs = srp_sq_size / 2;
 	qp_init->cap.max_send_sge = min(attrs->max_sge, SRPT_MAX_SG_PER_WQE);
 	qp_init->port_num = ch->sport->port;
+	if (sdev->use_srq) {
+		qp_init->srq = sdev->srq;
+	} else {
+		qp_init->cap.max_recv_wr = ch->rq_size;
+		qp_init->cap.max_recv_sge = qp_init->cap.max_send_sge;
+	}
 
 	ch->qp = ib_create_qp(sdev->pd, qp_init);
 	if (IS_ERR(ch->qp)) {
@@ -1669,6 +1687,10 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 		goto err_destroy_cq;
 	}
 
+	if (!sdev->use_srq)
+		for (i = 0; i < ch->rq_size; i++)
+			srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
+
 	atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
 
 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
@@ -1818,6 +1840,10 @@ static void srpt_release_channel_work(struct work_struct *w)
 			     ch->sport->sdev, ch->rq_size,
 			     ch->rsp_size, DMA_TO_DEVICE);
 
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
+			     sdev, ch->rq_size,
+			     srp_max_req_size, DMA_FROM_DEVICE);
+
 	mutex_lock(&sdev->mutex);
 	list_del_init(&ch->list);
 	if (ch->release_done)
@@ -1975,6 +2001,19 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
 		ch->ioctx_ring[i]->ch = ch;
 		list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
 	}
+	if (!sdev->use_srq) {
+		ch->ioctx_recv_ring = (struct srpt_recv_ioctx **)
+			srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
+					      sizeof(*ch->ioctx_recv_ring[0]),
+					      srp_max_req_size,
+					      DMA_FROM_DEVICE);
+		if (!ch->ioctx_recv_ring) {
+			pr_err("rejected SRP_LOGIN_REQ because creating a new QP RQ ring failed.\n");
+			rej->reason =
+			    cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
+			goto free_ring;
+		}
+	}
 
 	ret = srpt_create_ch_ib(ch);
 	if (ret) {
@@ -1982,7 +2021,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
 		pr_err("rejected SRP_LOGIN_REQ because creating"
 		       " a new RDMA channel failed.\n");
-		goto free_ring;
+		goto free_recv_ring;
 	}
 
 	ret = srpt_ch_qp_rtr(ch, ch->qp);
@@ -2073,6 +2112,11 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
 destroy_ib:
 	srpt_destroy_ch_ib(ch);
 
+free_recv_ring:
+	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
+			     ch->sport->sdev, ch->rq_size,
+			     srp_max_req_size, DMA_FROM_DEVICE);
+
 free_ring:
 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
 			     ch->sport->sdev, ch->rq_size,
@@ -2502,20 +2546,38 @@ static void srpt_add_one(struct ib_device *device)
 	srq_attr.attr.srq_limit = 0;
 	srq_attr.srq_type = IB_SRQT_BASIC;
 
-	sdev->srq = ib_create_srq(sdev->pd, &srq_attr);
-	if (IS_ERR(sdev->srq))
-		goto err_pd;
+	sdev->srq = sdev->port[0].port_attrib.use_srq ?
+		ib_create_srq(sdev->pd, &srq_attr) : ERR_PTR(-ENOTSUPP);
+	if (IS_ERR(sdev->srq)) {
+		pr_debug("ib_create_srq() failed: %ld\n", PTR_ERR(sdev->srq));
+
+		/* SRQ not supported. */
+		sdev->use_srq = false;
+	} else {
+		pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n",
+			 sdev->srq_size, sdev->device->attrs.max_srq_wr,
+			 device->name);
+
+		sdev->use_srq = true;
 
-	pr_debug("%s: create SRQ #wr= %d max_allow=%d dev= %s\n",
-		 __func__, sdev->srq_size, sdev->device->attrs.max_srq_wr,
-		 device->name);
+		sdev->ioctx_ring = (struct srpt_recv_ioctx **)
+			srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
+					      sizeof(*sdev->ioctx_ring[0]),
+					      srp_max_req_size,
+					      DMA_FROM_DEVICE);
+		if (!sdev->ioctx_ring)
+			goto err_pd;
+
+		for (i = 0; i < sdev->srq_size; ++i)
+			srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
+	}
 
 	if (!srpt_service_guid)
 		srpt_service_guid = be64_to_cpu(device->node_guid);
 
 	sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
 	if (IS_ERR(sdev->cm_id))
-		goto err_srq;
+		goto err_ring;
 
 	/* print out target login information */
 	pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,"
@@ -2535,16 +2597,6 @@ static void srpt_add_one(struct ib_device *device)
 			      srpt_event_handler);
 	ib_register_event_handler(&sdev->event_handler);
 
-	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
-		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
-				      sizeof(*sdev->ioctx_ring[0]),
-				      srp_max_req_size, DMA_FROM_DEVICE);
-	if (!sdev->ioctx_ring)
-		goto err_event;
-
-	for (i = 0; i < sdev->srq_size; ++i)
-		srpt_post_recv(sdev, sdev->ioctx_ring[i]);
-
 	WARN_ON(sdev->device->phys_port_cnt > ARRAY_SIZE(sdev->port));
 
 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
@@ -2554,12 +2606,13 @@ static void srpt_add_one(struct ib_device *device)
 		sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
 		sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
 		sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
+		sport->port_attrib.use_srq = false;
 		INIT_WORK(&sport->work, srpt_refresh_port_work);
 
 		if (srpt_refresh_port(sport)) {
 			pr_err("MAD registration failed for %s-%d.\n",
 			       sdev->device->name, i);
-			goto err_ring;
+			goto err_event;
 		}
 	}
 
@@ -2572,16 +2625,16 @@ static void srpt_add_one(struct ib_device *device)
 	pr_debug("added %s.\n", device->name);
 	return;
 
-err_ring:
-	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
-			     sdev->srq_size, srp_max_req_size,
-			     DMA_FROM_DEVICE);
 err_event:
 	ib_unregister_event_handler(&sdev->event_handler);
 err_cm:
 	ib_destroy_cm_id(sdev->cm_id);
-err_srq:
-	ib_destroy_srq(sdev->srq);
+err_ring:
+	if (sdev->use_srq)
+		ib_destroy_srq(sdev->srq);
+	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
+			     sdev->srq_size, srp_max_req_size,
+			     DMA_FROM_DEVICE);
 err_pd:
 	ib_dealloc_pd(sdev->pd);
 free_dev:
@@ -2625,12 +2678,12 @@ static void srpt_remove_one(struct ib_device *device, void *client_data)
 	spin_unlock(&srpt_dev_lock);
 	srpt_release_sdev(sdev);
 
-	ib_destroy_srq(sdev->srq);
-	ib_dealloc_pd(sdev->pd);
-
+	if (sdev->use_srq)
+		ib_destroy_srq(sdev->srq);
 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
 			     sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
-	sdev->ioctx_ring = NULL;
+	ib_dealloc_pd(sdev->pd);
+
 	kfree(sdev);
 }
 
@@ -2928,14 +2981,43 @@ static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t srpt_tpg_attrib_use_srq_show(struct config_item *item,
+					    char *page)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+
+	return sprintf(page, "%d\n", sport->port_attrib.use_srq);
+}
+
+static ssize_t srpt_tpg_attrib_use_srq_store(struct config_item *item,
+					     const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(page, 0, &val);
+	if (ret < 0)
+		return ret;
+	if (val != !!val)
+		return -EINVAL;
+	sport->port_attrib.use_srq = val;
+
+	return count;
+}
+
 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
+CONFIGFS_ATTR(srpt_tpg_attrib_,  use_srq);
 
 static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
 	&srpt_tpg_attrib_attr_srp_max_rdma_size,
 	&srpt_tpg_attrib_attr_srp_max_rsp_size,
 	&srpt_tpg_attrib_attr_srp_sq_size,
+	&srpt_tpg_attrib_attr_use_srq,
 	NULL,
 };
 
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
index 976e924d7400..673387d365a3 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.h
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -252,6 +252,7 @@ enum rdma_ch_state {
  * @free_list:     Head of list with free send I/O contexts.
  * @state:         channel state. See also enum rdma_ch_state.
  * @ioctx_ring:    Send ring.
+ * @ioctx_recv_ring: Receive I/O context ring.
  * @list:          Node for insertion in the srpt_device.rch_list list.
  * @cmd_wait_list: List of SCSI commands that arrived before the RTU event. This
  *                 list contains struct srpt_ioctx elements and is protected
@@ -281,6 +282,7 @@ struct srpt_rdma_ch {
 	struct list_head	free_list;
 	enum rdma_ch_state	state;
 	struct srpt_send_ioctx	**ioctx_ring;
+	struct srpt_recv_ioctx	**ioctx_recv_ring;
 	struct list_head	list;
 	struct list_head	cmd_wait_list;
 	struct se_session	*sess;
@@ -295,11 +297,13 @@ struct srpt_rdma_ch {
  * @srp_max_rdma_size: Maximum size of SRP RDMA transfers for new connections.
  * @srp_max_rsp_size: Maximum size of SRP response messages in bytes.
  * @srp_sq_size: Shared receive queue (SRQ) size.
+ * @use_srq: Whether or not to use SRQ.
  */
 struct srpt_port_attrib {
 	u32			srp_max_rdma_size;
 	u32			srp_max_rsp_size;
 	u32			srp_sq_size;
+	bool			use_srq;
 };
 
 /**
@@ -347,6 +351,7 @@ struct srpt_port {
  * @srq:           Per-HCA SRQ (shared receive queue).
  * @cm_id:         Connection identifier.
  * @srq_size:      SRQ size.
+ * @use_srq:       Whether or not to use SRQ.
  * @ioctx_ring:    Per-HCA SRQ.
  * @rch_list:      Per-device channel list -- see also srpt_rdma_ch.list.
  * @ch_releaseQ:   Enables waiting for removal from rch_list.
@@ -362,6 +367,7 @@ struct srpt_device {
 	struct ib_srq		*srq;
 	struct ib_cm_id		*cm_id;
 	int			srq_size;
+	bool			use_srq;
 	struct srpt_recv_ioctx	**ioctx_ring;
 	struct list_head	rch_list;
 	wait_queue_head_t	ch_releaseQ;
-- 
2.14.2

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RE: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Marciniszyn, Mike]

> Subject: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to
> using RC
> 

Bart, this last of the 4 target patches causes our internal SRP testing to fail.

> From the IB spec:
> 
>     C9-150.2.1: For QPs that are not associated with an SRQ, each HCA
>     receive queue shall generate end-to-end flow control credits. If
>     a QP is associated with an SRQ, the HCA receive queue shall not
>     generate end-to-end flow control credits.
> 

I'm looking at why but...

> Add new configfs attributes that allow to configure which mode to use
> (/sys/kernel/config/target/srpt/$GUID/$GUID/attrib/use_srq). Note:
> only the attribute for port 1 is relevant on multi-port adapters.
> 

It looks like the above work around cannot work.

The use_srq is tested and the  SRQ is allocated when the device is added.

Setting a target relative attribute is too late in the sequence to enable the old SRQ usage.

I hardwired the SRQ creation in srpt_add_one() to verify it works.

I suspect you may want to unconditionally create the SRQ and change the usage at login time based on the target flag?

Mike
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Re: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Bart Van Assche]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1147 bytes --]

On Thu, 2017-11-02 at 18:30 +0000, Marciniszyn, Mike wrote:
> > Subject: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to
> > using RC
> 
> Bart, this last of the 4 target patches causes our internal SRP testing to
> fail.

Sorry for this. Since I assume that you are referring to tests with the qib
or hfi1 driver and since I do not have access to a setup with that hardware
I will have to rely on you for further analysis.

> I'm looking at why but...
> 
> > Add new configfs attributes that allow to configure which mode to use
> > (/sys/kernel/config/target/srpt/$GUID/$GUID/attrib/use_srq). Note:
> > only the attribute for port 1 is relevant on multi-port adapters.
> 
> It looks like the above work around cannot work.
> The use_srq is tested and the  SRQ is allocated when the device is added.
> Setting a target relative attribute is too late in the sequence to enable
> the old SRQ usage.

Thanks for the report. I will post a patch series to address this.

Bart.N‹§²æìr¸›yúèšØb²X¬¶Ç§vØ^–)Þº{.nÇ+‰·¥Š{±­ÙšŠ{ayº\x1dʇڙë,j\a­¢f£¢·hš‹»öì\x17/oSc¾™Ú³9˜uÀ¦æå‰È&jw¨®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿïêäz¹Þ–Šàþf£¢·hšˆ§~ˆmš

RE: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Marciniszyn, Mike]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1354 bytes --]

> 
> Sorry for this. Since I assume that you are referring to tests with the qib
> or hfi1 driver and since I do not have access to a setup with that hardware
> I will have to rely on you for further analysis.

I turned on some static tracing and there is a sequence of RNR naks on the wire from the target.

A cursory look at the normal ACK aeth doesn't show any issue with the flow control.

Again, still looking.

I don't know if qib fails, but I suspect it will.

We have nightly 12 hour tests on the lastest stuff that caught it.

> 
> > I'm looking at why but...
> >
> > > Add new configfs attributes that allow to configure which mode to use
> > > (/sys/kernel/config/target/srpt/$GUID/$GUID/attrib/use_srq). Note:
> > > only the attribute for port 1 is relevant on multi-port adapters.
> >
> > It looks like the above work around cannot work.
> > The use_srq is tested and the  SRQ is allocated when the device is added.
> > Setting a target relative attribute is too late in the sequence to enable
> > the old SRQ usage.
> 
> Thanks for the report. I will post a patch series to address this.
> 

Ok.

For now I can just manually disarm with a code change to experiment.

Mike
N‹§²æìr¸›yúèšØb²X¬¶Ç§vØ^–)Þº{.nÇ+‰·¥Š{±­ÙšŠ{ayº\x1dʇڙë,j\a­¢f£¢·hš‹»öì\x17/oSc¾™Ú³9˜uÀ¦æå‰È&jw¨®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿïêäz¹Þ–Šàþf£¢·hšˆ§~ˆmš

RE: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Marciniszyn, Mike]

> I turned on some static tracing and there is a sequence of RNR naks on the
> wire from the target.
> 

The RNR naks are happening because ALL post receives fail in a QP state of reset.

Mike

RE: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Marciniszyn, Mike]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1270 bytes --]

> The RNR naks are happening because ALL post receives fail in a QP state of
> reset.
> 

Moving the post receives till after the init works:

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 304855b..98b1b80 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1687,10 +1687,6 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
                goto err_destroy_cq;
        }

-       if (!sdev->use_srq)
-               for (i = 0; i < ch->rq_size; i++)
-                       srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
-
        atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);

        pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
@@ -1701,6 +1697,10 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
        if (ret)
                goto err_destroy_qp;

+       if (!sdev->use_srq)
+               for (i = 0; i < ch->rq_size; i++)
+                       srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
+
 out:
        kfree(qp_init);
        return ret;
N‹§²æìr¸›yúèšØb²X¬¶Ç§vØ^–)Þº{.nÇ+‰·¥Š{±­ÙšŠ{ayº\x1dʇڙë,j\a­¢f£¢·hš‹»öì\x17/oSc¾™Ú³9˜uÀ¦æå‰È&jw¨®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿïêäz¹Þ–Šàþf£¢·hšˆ§~ˆmš

Re: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Bart Van Assche]

On Fri, 2017-11-03 at 16:01 +0000, Marciniszyn, Mike wrote:
> > The RNR naks are happening because ALL post receives fail in a QP state of
> > reset.
> > 
> 
> Moving the post receives till after the init works:
> 
> diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
> index 304855b..98b1b80 100644
> --- a/drivers/infiniband/ulp/srpt/ib_srpt.c
> +++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
> @@ -1687,10 +1687,6 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
>                 goto err_destroy_cq;
>         }
> 
> -       if (!sdev->use_srq)
> -               for (i = 0; i < ch->rq_size; i++)
> -                       srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
> -
>         atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
> 
>         pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
> @@ -1701,6 +1697,10 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
>         if (ret)
>                 goto err_destroy_qp;
> 
> +       if (!sdev->use_srq)
> +               for (i = 0; i < ch->rq_size; i++)
> +                       srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
> +
>  out:
>         kfree(qp_init);
>         return ret;

Thanks Mike for your work and this patch. I will test this patch further and
include it when I post the patches for fixing the behavior of the configfs
"use_srq" attribute.

Bart.

RE: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Marciniszyn, Mike]

> Thanks Mike for your work and this patch. I will test this patch further and
> include it when I post the patches for fixing the behavior of the configfs
> "use_srq" attribute.
> 

I run run our more extensive tests.

Right now, I've only run a simple unit test.

Mike

RE: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Marciniszyn, Mike]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 409 bytes --]

> I run run our more extensive tests.
> 

Our more extensive tests have passed.

I wonder if it is better to squash the move of the post receives with this patch to insure it bisects.

Fixing up the fallback stuff can certainly be additional patches.

Doug?

Mike
N‹§²æìr¸›yúèšØb²X¬¶Ç§vØ^–)Þº{.nÇ+‰·¥Š{±­ÙšŠ{ayº\x1dʇڙë,j\a­¢f£¢·hš‹»öì\x17/oSc¾™Ú³9˜uÀ¦æå‰È&jw¨®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿïêäz¹Þ–Šàþf£¢·hšˆ§~ˆmš

Re: [PATCH v2 4/8] IB/srpt: Change default behavior from using SRQ to using RC

[Doug Ledford]

[-- Attachment #1: Type: text/plain, Size: 715 bytes --]

On Fri, 2017-11-03 at 19:53 +0000, Marciniszyn, Mike wrote:
> > I run run our more extensive tests.
> > 
> 
> Our more extensive tests have passed.
> 
> I wonder if it is better to squash the move of the post receives with this patch to insure it bisects.
> 
> Fixing up the fallback stuff can certainly be additional patches.
> 
> Doug?

Sorry, the original patch has already been pushed to k.o, so it's in
stone at this point.  The break in bisectability is less egregious than
the break caused by a rebase of that code.

-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
    GPG KeyID: B826A3330E572FDD
    Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[PATCH v2 6/8] IB/srp: Remove second argument of srp_destroy_qp()

[Bart Van Assche]

This patch does not change any functionality.

Signed-off-by: Bart Van Assche <bart.vanassche-Sjgp3cTcYWE@public.gmane.org>
Reviewed-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 8ceb4bb011f1..96750ad253c4 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -464,20 +464,20 @@ static struct srp_fr_pool *srp_alloc_fr_pool(struct srp_target_port *target)
 
 /**
  * srp_destroy_qp() - destroy an RDMA queue pair
- * @qp: RDMA queue pair.
+ * @ch: SRP RDMA channel.
  *
  * Drain the qp before destroying it.  This avoids that the receive
  * completion handler can access the queue pair while it is
  * being destroyed.
  */
-static void srp_destroy_qp(struct srp_rdma_ch *ch, struct ib_qp *qp)
+static void srp_destroy_qp(struct srp_rdma_ch *ch)
 {
 	spin_lock_irq(&ch->lock);
 	ib_process_cq_direct(ch->send_cq, -1);
 	spin_unlock_irq(&ch->lock);
 
-	ib_drain_qp(qp);
-	ib_destroy_qp(qp);
+	ib_drain_qp(ch->qp);
+	ib_destroy_qp(ch->qp);
 }
 
 static int srp_create_ch_ib(struct srp_rdma_ch *ch)
@@ -550,7 +550,7 @@ static int srp_create_ch_ib(struct srp_rdma_ch *ch)
 	}
 
 	if (ch->qp)
-		srp_destroy_qp(ch, ch->qp);
+		srp_destroy_qp(ch);
 	if (ch->recv_cq)
 		ib_free_cq(ch->recv_cq);
 	if (ch->send_cq)
@@ -617,7 +617,7 @@ static void srp_free_ch_ib(struct srp_target_port *target,
 			ib_destroy_fmr_pool(ch->fmr_pool);
 	}
 
-	srp_destroy_qp(ch, ch->qp);
+	srp_destroy_qp(ch);
 	ib_free_cq(ch->send_cq);
 	ib_free_cq(ch->recv_cq);
 
-- 
2.14.2

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[PATCH v2 7/8] IB/srp: Cache global rkey

[Bart Van Assche]

This is a micro-optimization for the hot path.

Signed-off-by: Bart Van Assche <bart.vanassche-Sjgp3cTcYWE@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 27 ++++++++++++++-------------
 drivers/infiniband/ulp/srp/ib_srp.h |  3 ++-
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 96750ad253c4..463c3ed440eb 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1292,7 +1292,6 @@ static int srp_map_finish_fmr(struct srp_map_state *state,
 {
 	struct srp_target_port *target = ch->target;
 	struct srp_device *dev = target->srp_host->srp_dev;
-	struct ib_pd *pd = target->pd;
 	struct ib_pool_fmr *fmr;
 	u64 io_addr = 0;
 
@@ -1308,9 +1307,9 @@ static int srp_map_finish_fmr(struct srp_map_state *state,
 	if (state->npages == 0)
 		return 0;
 
-	if (state->npages == 1 && (pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)) {
+	if (state->npages == 1 && target->global_rkey) {
 		srp_map_desc(state, state->base_dma_addr, state->dma_len,
-			     pd->unsafe_global_rkey);
+			     target->global_rkey);
 		goto reset_state;
 	}
 
@@ -1350,7 +1349,6 @@ static int srp_map_finish_fr(struct srp_map_state *state,
 {
 	struct srp_target_port *target = ch->target;
 	struct srp_device *dev = target->srp_host->srp_dev;
-	struct ib_pd *pd = target->pd;
 	struct ib_send_wr *bad_wr;
 	struct ib_reg_wr wr;
 	struct srp_fr_desc *desc;
@@ -1366,12 +1364,12 @@ static int srp_map_finish_fr(struct srp_map_state *state,
 
 	WARN_ON_ONCE(!dev->use_fast_reg);
 
-	if (sg_nents == 1 && (pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)) {
+	if (sg_nents == 1 && target->global_rkey) {
 		unsigned int sg_offset = sg_offset_p ? *sg_offset_p : 0;
 
 		srp_map_desc(state, sg_dma_address(state->sg) + sg_offset,
 			     sg_dma_len(state->sg) - sg_offset,
-			     pd->unsafe_global_rkey);
+			     target->global_rkey);
 		if (sg_offset_p)
 			*sg_offset_p = 0;
 		return 1;
@@ -1533,7 +1531,7 @@ static int srp_map_sg_dma(struct srp_map_state *state, struct srp_rdma_ch *ch,
 	for_each_sg(scat, sg, count, i) {
 		srp_map_desc(state, ib_sg_dma_address(dev->dev, sg),
 			     ib_sg_dma_len(dev->dev, sg),
-			     target->pd->unsafe_global_rkey);
+			     target->global_rkey);
 	}
 
 	return 0;
@@ -1631,7 +1629,6 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 			struct srp_request *req)
 {
 	struct srp_target_port *target = ch->target;
-	struct ib_pd *pd = target->pd;
 	struct scatterlist *scat;
 	struct srp_cmd *cmd = req->cmd->buf;
 	int len, nents, count, ret;
@@ -1667,7 +1664,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 	fmt = SRP_DATA_DESC_DIRECT;
 	len = sizeof (struct srp_cmd) +	sizeof (struct srp_direct_buf);
 
-	if (count == 1 && (pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)) {
+	if (count == 1 && target->global_rkey) {
 		/*
 		 * The midlayer only generated a single gather/scatter
 		 * entry, or DMA mapping coalesced everything to a
@@ -1677,7 +1674,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 		struct srp_direct_buf *buf = (void *) cmd->add_data;
 
 		buf->va  = cpu_to_be64(ib_sg_dma_address(ibdev, scat));
-		buf->key = cpu_to_be32(pd->unsafe_global_rkey);
+		buf->key = cpu_to_be32(target->global_rkey);
 		buf->len = cpu_to_be32(ib_sg_dma_len(ibdev, scat));
 
 		req->nmdesc = 0;
@@ -1748,14 +1745,14 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 	memcpy(indirect_hdr->desc_list, req->indirect_desc,
 	       count * sizeof (struct srp_direct_buf));
 
-	if (!(pd->flags & IB_PD_UNSAFE_GLOBAL_RKEY)) {
+	if (!target->global_rkey) {
 		ret = srp_map_idb(ch, req, state.gen.next, state.gen.end,
 				  idb_len, &idb_rkey);
 		if (ret < 0)
 			goto unmap;
 		req->nmdesc++;
 	} else {
-		idb_rkey = cpu_to_be32(pd->unsafe_global_rkey);
+		idb_rkey = cpu_to_be32(target->global_rkey);
 	}
 
 	indirect_hdr->table_desc.va = cpu_to_be64(req->indirect_dma_addr);
@@ -3331,8 +3328,8 @@ static ssize_t srp_create_target(struct device *dev,
 	target->io_class	= SRP_REV16A_IB_IO_CLASS;
 	target->scsi_host	= target_host;
 	target->srp_host	= host;
-	target->pd		= host->srp_dev->pd;
 	target->lkey		= host->srp_dev->pd->local_dma_lkey;
+	target->global_rkey	= host->srp_dev->global_rkey;
 	target->cmd_sg_cnt	= cmd_sg_entries;
 	target->sg_tablesize	= indirect_sg_entries ? : cmd_sg_entries;
 	target->allow_ext_sg	= allow_ext_sg;
@@ -3651,6 +3648,10 @@ static void srp_add_one(struct ib_device *device)
 	if (IS_ERR(srp_dev->pd))
 		goto free_dev;
 
+	if (flags & IB_PD_UNSAFE_GLOBAL_RKEY) {
+		srp_dev->global_rkey = srp_dev->pd->unsafe_global_rkey;
+		WARN_ON_ONCE(srp_dev->global_rkey == 0);
+	}
 
 	for (p = rdma_start_port(device); p <= rdma_end_port(device); ++p) {
 		host = srp_add_port(srp_dev, p);
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index ab9077b81d5a..a814f5ef16f9 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -90,6 +90,7 @@ struct srp_device {
 	struct list_head	dev_list;
 	struct ib_device       *dev;
 	struct ib_pd	       *pd;
+	u32			global_rkey;
 	u64			mr_page_mask;
 	int			mr_page_size;
 	int			mr_max_size;
@@ -179,7 +180,7 @@ struct srp_target_port {
 	spinlock_t		lock;
 
 	/* read only in the hot path */
-	struct ib_pd		*pd;
+	u32			global_rkey;
 	struct srp_rdma_ch	*ch;
 	u32			ch_count;
 	u32			lkey;
-- 
2.14.2

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[PATCH v2 8/8] IB/srp: Make CM timeout dependent on subnet timeout

[Bart Van Assche]

For small networks it is safe to reduce the subnet timeout from
its default value (18 for opensm) to 16. Make the SRP CM timeout
dependent on the subnet timeout such that decreasing the subnet
timeout also causes SRP failover and failback to occur faster.

Signed-off-by: Bart Van Assche <bart.vanassche-Sjgp3cTcYWE@public.gmane.org>
Reviewed-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 463c3ed440eb..972d4b3c5223 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -711,6 +711,23 @@ static int srp_lookup_path(struct srp_rdma_ch *ch)
 	return ret;
 }
 
+static u8 srp_get_subnet_timeout(struct srp_host *host)
+{
+	struct ib_port_attr attr;
+	int ret;
+	u8 subnet_timeout = 18;
+
+	ret = ib_query_port(host->srp_dev->dev, host->port, &attr);
+	if (ret == 0)
+		subnet_timeout = attr.subnet_timeout;
+
+	if (unlikely(subnet_timeout < 15))
+		pr_warn("%s: subnet timeout %d may cause SRP login to fail.\n",
+			dev_name(&host->srp_dev->dev->dev), subnet_timeout);
+
+	return subnet_timeout;
+}
+
 static int srp_send_req(struct srp_rdma_ch *ch, bool multich)
 {
 	struct srp_target_port *target = ch->target;
@@ -719,6 +736,9 @@ static int srp_send_req(struct srp_rdma_ch *ch, bool multich)
 		struct srp_login_req   priv;
 	} *req = NULL;
 	int status;
+	u8 subnet_timeout;
+
+	subnet_timeout = srp_get_subnet_timeout(target->srp_host);
 
 	req = kzalloc(sizeof *req, GFP_KERNEL);
 	if (!req)
@@ -741,8 +761,8 @@ static int srp_send_req(struct srp_rdma_ch *ch, bool multich)
 	 * module parameters if anyone cared about setting them.
 	 */
 	req->param.responder_resources	      = 4;
-	req->param.remote_cm_response_timeout = 20;
-	req->param.local_cm_response_timeout  = 20;
+	req->param.remote_cm_response_timeout = subnet_timeout + 2;
+	req->param.local_cm_response_timeout  = subnet_timeout + 2;
 	req->param.retry_count                = target->tl_retry_count;
 	req->param.rnr_retry_count 	      = 7;
 	req->param.max_cm_retries 	      = 15;
-- 
2.14.2

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Re: [PATCH v2 0/8] SRP patches for kernel v4.15

[Doug Ledford]

On Wed, 2017-10-11 at 10:27 -0700, Bart Van Assche wrote:
> Hello Doug,
> 
> This patch series includes several the SRP initiator and target
> patches I came
> up with during the past months. The initiator patches are independent
> of the
> target patches. Please consider these patches for kernel v4.15.
> 
> Thanks,
> 
> Bart.

Thanks Bart, series applied.

-- 
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[PATCH v2 5/8] IB/srp: Avoid that a cable pull can trigger a kernel crash

[Bart Van Assche]

This patch fixes the following kernel crash:

general protection fault: 0000 [#1] PREEMPT SMP
Workqueue: ib_mad2 timeout_sends [ib_core]
Call Trace:
 ib_sa_path_rec_callback+0x1c4/0x1d0 [ib_core]
 send_handler+0xb2/0xd0 [ib_core]
 timeout_sends+0x14d/0x220 [ib_core]
 process_one_work+0x200/0x630
 worker_thread+0x4e/0x3b0
 kthread+0x113/0x150

Fixes: commit aef9ec39c47f ("IB: Add SCSI RDMA Protocol (SRP) initiator")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Cc: <stable@vger.kernel.org>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 778a08250f16..8ceb4bb011f1 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -665,12 +665,19 @@ static void srp_path_rec_completion(int status,
 static int srp_lookup_path(struct srp_rdma_ch *ch)
 {
 	struct srp_target_port *target = ch->target;
-	int ret;
+	int ret = -ENODEV;
 
 	ch->path.numb_path = 1;
 
 	init_completion(&ch->done);
 
+	/*
+	 * Avoid that the SCSI host can be removed by srp_remove_target()
+	 * before srp_path_rec_completion() is called.
+	 */
+	if (!scsi_host_get(target->scsi_host))
+		goto out;
+
 	ch->path_query_id = ib_sa_path_rec_get(&srp_sa_client,
 					       target->srp_host->srp_dev->dev,
 					       target->srp_host->port,
@@ -684,18 +691,24 @@ static int srp_lookup_path(struct srp_rdma_ch *ch)
 					       GFP_KERNEL,
 					       srp_path_rec_completion,
 					       ch, &ch->path_query);
-	if (ch->path_query_id < 0)
-		return ch->path_query_id;
+	ret = ch->path_query_id;
+	if (ret < 0)
+		goto put;
 
 	ret = wait_for_completion_interruptible(&ch->done);
 	if (ret < 0)
-		return ret;
+		goto put;
 
-	if (ch->status < 0)
+	ret = ch->status;
+	if (ret < 0)
 		shost_printk(KERN_WARNING, target->scsi_host,
 			     PFX "Path record query failed\n");
 
-	return ch->status;
+put:
+	scsi_host_put(target->scsi_host);
+
+out:
+	return ret;
 }
 
 static int srp_send_req(struct srp_rdma_ch *ch, bool multich)
-- 
2.14.2