SRP initiator and target patches for kernel v5.8

PATCH Superseded Bart Van Assche 2 participants 8 messages May 22, 2020 – May 24, 2020

Subsystems (3)

InfiniBand SCSI RDMA protocol (SRP) initiator SCSI RDMA protocol (SRP) target

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Bart Van Assche

author maintainer

2020-05-22 21:33 UTC #0 lore raw

cover SRP initiator and target patches for kernel v5.8

Hi Jason,

Please consider these four patches for kernel v5.8.

Thanks,

Bart.

Bart Van Assche (4):
RDMA/srp: Make the channel count configurable per target RDMA/srpt: Make debug output more detailed RDMA/srpt: Reduce max_recv_sge to 1
RDMA/srpt: Increase max_send_sge

 drivers/infiniband/ulp/srp/ib_srp.c   | 21 ++++++++++---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 44 +++++++++++++++++++--------
 drivers/infiniband/ulp/srpt/ib_srpt.h |  5 ---
 3 files changed, 47 insertions(+), 23 deletions(-)

Bart Van Assche

author maintainer

2020-05-22 21:33 UTC #1 lore raw

PATCH 1/4 RDMA/srp: Make the channel count configurable per target

Increase the flexibility of the SRP initiator driver by making the channel count configurable per target instead of only providing a kernel module parameter for configuring the channel count.

Cc Laurence Oberman <[email protected]>

Cc Kamal Heib <[email protected]>

Signed-off-by Bart Van Assche <[email protected]>

---
 drivers/infiniband/ulp/srp/ib_srp.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

drivers/infiniband/ulp/srp/ib_srp.c +16 -5

index 00b4f88b113e..d686c39710c0 100644
@@ -3424,6 +3424,7 @@ enum {
 	SRP_OPT_IP_DEST		= 1 << 16,
 	SRP_OPT_TARGET_CAN_QUEUE= 1 << 17,
 	SRP_OPT_MAX_IT_IU_SIZE  = 1 << 18,
+	SRP_OPT_CH_COUNT	= 1 << 19,
 };
 
 static unsigned int srp_opt_mandatory[] = {

@@ -3457,6 +3458,7 @@ static const match_table_t srp_opt_tokens = {
 	{ SRP_OPT_IP_SRC,		"src=%s"		},
 	{ SRP_OPT_IP_DEST,		"dest=%s"		},
 	{ SRP_OPT_MAX_IT_IU_SIZE,	"max_it_iu_size=%d"	},
+	{ SRP_OPT_CH_COUNT,		"ch_count=%d",		},
 	{ SRP_OPT_ERR,			NULL 			}
 };

@@ -3758,6 +3760,14 @@ static int srp_parse_options(struct net *net, const char *buf,
 			target->max_it_iu_size = token;
 			break;
 
+		case SRP_OPT_CH_COUNT:
+			if (match_int(args, &token) || token < 1) {
+				pr_warn("bad channel count %s\n", p);
+				goto out;
+			}
+			target->ch_count = token;
+			break;
+
 		default:
 			pr_warn("unknown parameter or missing value '%s' in target creation request\n",
 				p);

@@ -3921,11 +3931,12 @@ static ssize_t srp_create_target(struct device *dev,
 		goto out;
 
 	ret = -ENOMEM;
-	target->ch_count = max_t(unsigned, num_online_nodes(),
-				 min(ch_count ? :
-				     min(4 * num_online_nodes(),
-					 ibdev->num_comp_vectors),
-				     num_online_cpus()));
+	if (target->ch_count == 0)
+		target->ch_count = max_t(unsigned, num_online_nodes(),
+					 min(ch_count ? :
+					     min(4 * num_online_nodes(),
+						 ibdev->num_comp_vectors),
+					     num_online_cpus()));
 	target->ch = kcalloc(target->ch_count, sizeof(*target->ch),
 			     GFP_KERNEL);
 	if (!target->ch)

Bart Van Assche

author maintainer

2020-05-23 15:22 UTC #3 lore raw

Re: [PATCH 1/4] RDMA/srp: Make the channel count configurable per target

Quoted 23 lines · Leon Romanovsky

Quoted 22 lines · Bart Van Assche
Increase the flexibility of the SRP initiator driver by making the channel count configurable per target instead of only providing a kernel module parameter for configuring the channel count.
Cc Laurence Oberman <[email protected]>
Cc Kamal Heib <[email protected]>
Signed-off-by Bart Van Assche <[email protected]>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)
drivers/infiniband/ulp/srp/ib_srp.c +1 -0
index 00b4f88b113e..d686c39710c0 100644
@@ -3424,6 +3424,7 @@ enum {
 	SRP_OPT_IP_DEST		= 1 << 16,
 	SRP_OPT_TARGET_CAN_QUEUE= 1 << 17,
 	SRP_OPT_MAX_IT_IU_SIZE  = 1 << 18,
+	SRP_OPT_CH_COUNT	= 1 << 19,
 };
 

Quoted 8 lines

drivers/infiniband/ulp/srp/ib_srp.c static const match_table_t srp_opt_tokens = { · line 3461
Quoted 6 lines
drivers/infiniband/ulp/srp/ib_srp.c +1 -0
 static unsigned int srp_opt_mandatory[] = {
@@ -3457,6 +3458,7 @@ static const match_table_t srp_opt_tokens = {
 	{ SRP_OPT_IP_SRC,		"src=%s"		},
 	{ SRP_OPT_IP_DEST,		"dest=%s"		},
 	{ SRP_OPT_MAX_IT_IU_SIZE,	"max_it_iu_size=%d"	},
+	{ SRP_OPT_CH_COUNT,		"ch_count=%d",		},
Why did you use %d and not %u?

Hi Leon,

There is more kernel code that uses %d for unsigned integers. Anyway, if someone cares enough I can change %d into %u.

Bart.

Leon Romanovsky

2020-05-24 06:21 UTC #4 lore raw

Re: [PATCH 1/4] RDMA/srp: Make the channel count configurable per target

Quoted 33 lines · Bart Van Assche

Quoted 23 lines · Leon Romanovsky
Quoted 22 lines · Bart Van Assche
Increase the flexibility of the SRP initiator driver by making the channel count configurable per target instead of only providing a kernel module parameter for configuring the channel count.
Cc Laurence Oberman <[email protected]>
Cc Kamal Heib <[email protected]>
Signed-off-by Bart Van Assche <[email protected]>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)
drivers/infiniband/ulp/srp/ib_srp.c +1 -0
index 00b4f88b113e..d686c39710c0 100644
@@ -3424,6 +3424,7 @@ enum {
 	SRP_OPT_IP_DEST		= 1 << 16,
 	SRP_OPT_TARGET_CAN_QUEUE= 1 << 17,
 	SRP_OPT_MAX_IT_IU_SIZE  = 1 << 18,
+	SRP_OPT_CH_COUNT	= 1 << 19,
 };
 
Quoted 8 lines
drivers/infiniband/ulp/srp/ib_srp.c static const match_table_t srp_opt_tokens = { · line 3461
Quoted 6 lines
drivers/infiniband/ulp/srp/ib_srp.c +1 -0
 static unsigned int srp_opt_mandatory[] = {
@@ -3457,6 +3458,7 @@ static const match_table_t srp_opt_tokens = {
 	{ SRP_OPT_IP_SRC,		"src=%s"		},
 	{ SRP_OPT_IP_DEST,		"dest=%s"		},
 	{ SRP_OPT_MAX_IT_IU_SIZE,	"max_it_iu_size=%d"	},
+	{ SRP_OPT_CH_COUNT,		"ch_count=%d",		},
Why did you use %d and not %u?

Quoted 4 lines

Hi Leon,
There is more kernel code that uses %d for unsigned integers. Anyway, if someone cares enough I can change %d into %u.

I don't have strong opinion about that.

Thanks

Quoted 2 lines

Bart.

Bart Van Assche

author maintainer

2020-05-22 21:33 UTC #5 lore raw

PATCH 2/4 RDMA/srpt: Make debug output more detailed

In reply to Bart Van Assche

Since the session name by itself is not sufficient to uniquely identify a queue pair, include the queue pair number. Show the ASCII channel state name instead of the numeric value. This change makes the ib_srpt debug output more consistent.

Cc Laurence Oberman <[email protected]>

Cc Kamal Heib <[email protected]>

Signed-off-by Bart Van Assche <[email protected]>

---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

drivers/infiniband/ulp/srpt/ib_srpt.c +5 -4

index a294630f2100..a39ad9fc4224 100644
@@ -214,8 +214,9 @@ static const char *get_ch_state_name(enum rdma_ch_state s)
  */
 static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
 {
-	pr_debug("QP event %d on ch=%p sess_name=%s state=%d\n",
-		 event->event, ch, ch->sess_name, ch->state);
+	pr_debug("QP event %d on ch=%p sess_name=%s-%d state=%s\n",
+		 event->event, ch, ch->sess_name, ch->qp->qp_num,
+		 get_ch_state_name(ch->state));
 
 	switch (event->event) {
 	case IB_EVENT_COMM_EST:

@@ -1985,8 +1986,8 @@ static void __srpt_close_all_ch(struct srpt_port *sport)
 	list_for_each_entry(nexus, &sport->nexus_list, entry) {
 		list_for_each_entry(ch, &nexus->ch_list, list) {
 			if (srpt_disconnect_ch(ch) >= 0)
-				pr_info("Closing channel %s because target %s_%d has been disabled\n",
-					ch->sess_name,
+				pr_info("Closing channel %s-%d because target %s_%d has been disabled\n",
+					ch->sess_name, ch->qp->qp_num,
 					dev_name(&sport->sdev->device->dev),
 					sport->port);
 			srpt_close_ch(ch);

Bart Van Assche

author maintainer

2020-05-22 21:33 UTC #6 lore raw

PATCH 3/4 RDMA/srpt: Reduce max_recv_sge to 1

In reply to Bart Van Assche

Since srpt_post_recv() always sets num_sge to 1, reduce the max_recv_sge parameter that is used at queue pair allocation time to 1.

Cc Laurence Oberman <[email protected]>

Cc Kamal Heib <[email protected]>

Signed-off-by Bart Van Assche <[email protected]>

---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

drivers/infiniband/ulp/srpt/ib_srpt.c +3 -7

index a39ad9fc4224..1ad3cc7c553a 100644
@@ -1818,16 +1818,12 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 	qp_init->cap.max_rdma_ctxs = sq_size / 2;
 	qp_init->cap.max_send_sge = min(attrs->max_send_sge,
 					SRPT_MAX_SG_PER_WQE);
-	qp_init->cap.max_recv_sge = min(attrs->max_recv_sge,
-					SRPT_MAX_SG_PER_WQE);
+	qp_init->cap.max_recv_sge = 1;
 	qp_init->port_num = ch->sport->port;
-	if (sdev->use_srq) {
+	if (sdev->use_srq)
 		qp_init->srq = sdev->srq;
-	} else {
+	else
 		qp_init->cap.max_recv_wr = ch->rq_size;
-		qp_init->cap.max_recv_sge = min(attrs->max_recv_sge,
-						SRPT_MAX_SG_PER_WQE);
-	}
 
 	if (ch->using_rdma_cm) {
 		ret = rdma_create_qp(ch->rdma_cm.cm_id, sdev->pd, qp_init);

Bart Van Assche

author maintainer

2020-05-22 21:33 UTC #7 lore raw

PATCH 4/4 RDMA/srpt: Increase max_send_sge

In reply to Bart Van Assche

The ib_srpt driver limits max_send_sge to 16. Since that is a workaround for an mlx4 bug that has been fixed, increase max_send_sge. For mlx4, do not use the value advertised by the driver (32) since that causes QP's to transition to the error status.

See also commit f95ccffc715b ("IB/mlx4: Use 4K pages for kernel QP's WQE buffer").

Cc Laurence Oberman <[email protected]>

Cc Kamal Heib <[email protected]>

Signed-off-by Bart Van Assche <[email protected]>

---
 drivers/infiniband/ulp/srpt/ib_srpt.c | 25 +++++++++++++++++++++++--
 drivers/infiniband/ulp/srpt/ib_srpt.h |  5 -----
 2 files changed, 23 insertions(+), 7 deletions(-)

drivers/infiniband/ulp/srpt/ib_srpt.c +23 -2

index 1ad3cc7c553a..8d9b8664ea75 100644
@@ -1781,8 +1781,30 @@ 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;
 	int sq_size = sport->port_attrib.srp_sq_size;
+	unsigned int max_sge_delta = 0;
 	int i, ret;
 
+	switch (sdev->device->ops.driver_id) {
+	case RDMA_DRIVER_MLX4:
+		/*
+		 * The smallest max_sge_delta value that works with
+		 * ConnectX-3 firmware version 2.42.5000.
+		 */
+		max_sge_delta = 2;
+		break;
+	case RDMA_DRIVER_MTHCA:
+		/*
+		 * From the OFED release notes: In mem-free devices, RC
+		 * QPs can be created with a maximum of (max_sge - 1)
+		 * entries only. See also
+		 * https://git.openfabrics.org/?p=compat-rdma/docs.git;a=blob;f=release_notes/mthca_release_notes.txt;h=40f3c4ea77a07fe5ded888b8417530471e89d87b.
+		 */
+		max_sge_delta = 1;
+		break;
+	default:
+		break;
+	}
+
 	WARN_ON(ch->rq_size < 1);
 
 	ret = -ENOMEM;

@@ -1816,8 +1838,7 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
 	 */
 	qp_init->cap.max_send_wr = min(sq_size / 2, attrs->max_qp_wr);
 	qp_init->cap.max_rdma_ctxs = sq_size / 2;
-	qp_init->cap.max_send_sge = min(attrs->max_send_sge,
-					SRPT_MAX_SG_PER_WQE);
+	qp_init->cap.max_send_sge = attrs->max_send_sge - max_sge_delta;
 	qp_init->cap.max_recv_sge = 1;
 	qp_init->port_num = ch->sport->port;
 	if (sdev->use_srq)

drivers/infiniband/ulp/srpt/ib_srpt.h +0 -5

index 2e1a69840857..f31c349d07a1 100644
@@ -105,11 +105,6 @@ enum {
 	SRP_CMD_ACA = 0x4,
 
 	SRPT_DEF_SG_TABLESIZE = 128,
-	/*
-	 * An experimentally determined value that avoids that QP creation
-	 * fails due to "swiotlb buffer is full" on systems using the swiotlb.
-	 */
-	SRPT_MAX_SG_PER_WQE = 16,
 
 	MIN_SRPT_SQ_SIZE = 16,
 	DEF_SRPT_SQ_SIZE = 4096,