IB/srp: Make queue size configurable

Certain storage configurations, e.g. a sufficiently large array of
hard disks in a RAID configuration, need a queue depth above 64 to
achieve optimal performance. Hence make the queue depth configurable.

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

3 files changed, 107 insertions, 39 deletions

diff --git a/Documentation/ABI/stable/sysfs-driver-ib_srp b/Documentation/ABI/stable/sysfs-driver-ib_srp
index b95067eb5f18..b9688de8455b 100644
--- a/Documentation/ABI/stable/sysfs-driver-ib_srp
+++ b/Documentation/ABI/stable/sysfs-driver-ib_srp
@@ -63,6 +63,10 @@ Description:	Interface for making ib_srp connect to a new target.
                   over multiple CPU's.
                 * tl_retry_count, a number in the range 2..7 specifying the
                   IB RC retry count.
+                * queue_size, the maximum number of commands that the
+                  initiator is allowed to queue per SCSI host. The default
+                  value for this parameter is 62. The lowest supported value
+                  is 2.
 
 What:           /sys/class/infiniband_srp/srp-<hca>-<port_number>/ibdev
 Date:           January 2, 2006
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 735af11d9b82..6aa660d188a3 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -299,16 +299,16 @@ static int srp_create_target_ib(struct srp_target_port *target)
                 return -ENOMEM;
 
         recv_cq = ib_create_cq(target->srp_host->srp_dev->dev,
-                               srp_recv_completion, NULL, target, SRP_RQ_SIZE,
-                               target->comp_vector);
+                               srp_recv_completion, NULL, target,
+                               target->queue_size, target->comp_vector);
         if (IS_ERR(recv_cq)) {
                 ret = PTR_ERR(recv_cq);
                 goto err;
         }
 
         send_cq = ib_create_cq(target->srp_host->srp_dev->dev,
-                               srp_send_completion, NULL, target, SRP_SQ_SIZE,
-                               target->comp_vector);
+                               srp_send_completion, NULL, target,
+                               target->queue_size, target->comp_vector);
         if (IS_ERR(send_cq)) {
                 ret = PTR_ERR(send_cq);
                 goto err_recv_cq;
@@ -317,8 +317,8 @@ static int srp_create_target_ib(struct srp_target_port *target)
         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;
-        init_attr->cap.max_recv_wr     = SRP_RQ_SIZE;
+        init_attr->cap.max_send_wr     = target->queue_size;
+        init_attr->cap.max_recv_wr     = target->queue_size;
         init_attr->cap.max_recv_sge    = 1;
         init_attr->cap.max_send_sge    = 1;
         init_attr->sq_sig_type         = IB_SIGNAL_ALL_WR;
@@ -364,6 +364,10 @@ err:
         return ret;
 }
 
+/*
+ * Note: this function may be called without srp_alloc_iu_bufs() having been
+ * invoked. Hence the target->[rt]x_ring checks.
+ */
 static void srp_free_target_ib(struct srp_target_port *target)
 {
         int i;
@@ -375,10 +379,18 @@ static void srp_free_target_ib(struct srp_target_port *target)
         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)
-                srp_free_iu(target->srp_host, target->tx_ring[i]);
+        if (target->rx_ring) {
+                for (i = 0; i < target->queue_size; ++i)
+                        srp_free_iu(target->srp_host, target->rx_ring[i]);
+                kfree(target->rx_ring);
+                target->rx_ring = NULL;
+        }
+        if (target->tx_ring) {
+                for (i = 0; i < target->queue_size; ++i)
+                        srp_free_iu(target->srp_host, target->tx_ring[i]);
+                kfree(target->tx_ring);
+                target->tx_ring = NULL;
+        }
 }
 
 static void srp_path_rec_completion(int status,
@@ -564,7 +576,11 @@ static void srp_free_req_data(struct srp_target_port *target)
         struct srp_request *req;
         int i;
 
-        for (i = 0, req = target->req_ring; i < SRP_CMD_SQ_SIZE; ++i, ++req) {
+        if (!target->req_ring)
+                return;
+
+        for (i = 0; i < target->req_ring_size; ++i) {
+                req = &target->req_ring[i];
                 kfree(req->fmr_list);
                 kfree(req->map_page);
                 if (req->indirect_dma_addr) {
@@ -574,6 +590,9 @@ static void srp_free_req_data(struct srp_target_port *target)
                 }
                 kfree(req->indirect_desc);
         }
+
+        kfree(target->req_ring);
+        target->req_ring = NULL;
 }
 
 static int srp_alloc_req_data(struct srp_target_port *target)
@@ -586,7 +605,12 @@ static int srp_alloc_req_data(struct srp_target_port *target)
 
         INIT_LIST_HEAD(&target->free_reqs);
 
-        for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+        target->req_ring = kzalloc(target->req_ring_size *
+                                   sizeof(*target->req_ring), GFP_KERNEL);
+        if (!target->req_ring)
+                goto out;
+
+        for (i = 0; i < target->req_ring_size; ++i) {
                 req = &target->req_ring[i];
                 req->fmr_list = kmalloc(target->cmd_sg_cnt * sizeof(void *),
                                         GFP_KERNEL);
@@ -810,7 +834,7 @@ static void srp_terminate_io(struct srp_rport *rport)
         struct srp_target_port *target = rport->lld_data;
         int i;
 
-        for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+        for (i = 0; i < target->req_ring_size; ++i) {
                 struct srp_request *req = &target->req_ring[i];
                 srp_finish_req(target, req, DID_TRANSPORT_FAILFAST << 16);
         }
@@ -847,13 +871,13 @@ static int srp_rport_reconnect(struct srp_rport *rport)
         else
                 srp_create_target_ib(target);
 
-        for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+        for (i = 0; i < target->req_ring_size; ++i) {
                 struct srp_request *req = &target->req_ring[i];
                 srp_finish_req(target, req, DID_RESET << 16);
         }
 
         INIT_LIST_HEAD(&target->free_tx);
-        for (i = 0; i < SRP_SQ_SIZE; ++i)
+        for (i = 0; i < target->queue_size; ++i)
                 list_add(&target->tx_ring[i]->list, &target->free_tx);
 
         if (ret == 0)
@@ -1562,11 +1586,24 @@ err_unlock:
         return SCSI_MLQUEUE_HOST_BUSY;
 }
 
+/*
+ * Note: the resources allocated in this function are freed in
+ * srp_free_target_ib().
+ */
 static int srp_alloc_iu_bufs(struct srp_target_port *target)
 {
         int i;
 
-        for (i = 0; i < SRP_RQ_SIZE; ++i) {
+        target->rx_ring = kzalloc(target->queue_size * sizeof(*target->rx_ring),
+                                  GFP_KERNEL);
+        if (!target->rx_ring)
+                goto err_no_ring;
+        target->tx_ring = kzalloc(target->queue_size * sizeof(*target->tx_ring),
+                                  GFP_KERNEL);
+        if (!target->tx_ring)
+                goto err_no_ring;
+
+        for (i = 0; i < target->queue_size; ++i) {
                 target->rx_ring[i] = srp_alloc_iu(target->srp_host,
                                                   target->max_ti_iu_len,
                                                   GFP_KERNEL, DMA_FROM_DEVICE);
@@ -1574,7 +1611,7 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)
                         goto err;
         }
 
-        for (i = 0; i < SRP_SQ_SIZE; ++i) {
+        for (i = 0; i < target->queue_size; ++i) {
                 target->tx_ring[i] = srp_alloc_iu(target->srp_host,
                                                   target->max_iu_len,
                                                   GFP_KERNEL, DMA_TO_DEVICE);
@@ -1587,16 +1624,18 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)
         return 0;
 
 err:
-        for (i = 0; i < SRP_RQ_SIZE; ++i) {
+        for (i = 0; i < target->queue_size; ++i) {
                 srp_free_iu(target->srp_host, target->rx_ring[i]);
-                target->rx_ring[i] = NULL;
-        }
-
-        for (i = 0; i < SRP_SQ_SIZE; ++i) {
                 srp_free_iu(target->srp_host, target->tx_ring[i]);
-                target->tx_ring[i] = NULL;
         }
 
+
+err_no_ring:
+        kfree(target->tx_ring);
+        target->tx_ring = NULL;
+        kfree(target->rx_ring);
+        target->rx_ring = NULL;
+
         return -ENOMEM;
 }
 
@@ -1647,6 +1686,9 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
                 target->scsi_host->can_queue
                         = min(target->req_lim - SRP_TSK_MGMT_SQ_SIZE,
                               target->scsi_host->can_queue);
+                target->scsi_host->cmd_per_lun
+                        = min_t(int, target->scsi_host->can_queue,
+                                target->scsi_host->cmd_per_lun);
         } else {
                 shost_printk(KERN_WARNING, target->scsi_host,
                              PFX "Unhandled RSP opcode %#x\n", lrsp->opcode);
@@ -1654,7 +1696,7 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
                 goto error;
         }
 
-        if (!target->rx_ring[0]) {
+        if (!target->rx_ring) {
                 ret = srp_alloc_iu_bufs(target);
                 if (ret)
                         goto error;
@@ -1674,7 +1716,7 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
         if (ret)
                 goto error_free;
 
-        for (i = 0; i < SRP_RQ_SIZE; i++) {
+        for (i = 0; i < target->queue_size; i++) {
                 struct srp_iu *iu = target->rx_ring[i];
                 ret = srp_post_recv(target, iu);
                 if (ret)
@@ -1933,7 +1975,7 @@ static int srp_reset_device(struct scsi_cmnd *scmnd)
         if (target->tsk_mgmt_status)
                 return FAILED;
 
-        for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
+        for (i = 0; i < target->req_ring_size; ++i) {
                 struct srp_request *req = &target->req_ring[i];
                 if (req->scmnd && req->scmnd->device == scmnd->device)
                         srp_finish_req(target, req, DID_RESET << 16);
@@ -2136,9 +2178,9 @@ static struct scsi_host_template srp_template = {
         .eh_host_reset_handler          = srp_reset_host,
         .skip_settle_delay              = true,
         .sg_tablesize                   = SRP_DEF_SG_TABLESIZE,
-        .can_queue                      = SRP_CMD_SQ_SIZE,
+        .can_queue                      = SRP_DEFAULT_CMD_SQ_SIZE,
         .this_id                        = -1,
-        .cmd_per_lun                    = SRP_CMD_SQ_SIZE,
+        .cmd_per_lun                    = SRP_DEFAULT_CMD_SQ_SIZE,
         .use_clustering                 = ENABLE_CLUSTERING,
         .shost_attrs                    = srp_host_attrs
 };
@@ -2245,6 +2287,7 @@ enum {
         SRP_OPT_SG_TABLESIZE    = 1 << 11,
         SRP_OPT_COMP_VECTOR     = 1 << 12,
         SRP_OPT_TL_RETRY_COUNT  = 1 << 13,
+        SRP_OPT_QUEUE_SIZE      = 1 << 14,
         SRP_OPT_ALL             = (SRP_OPT_ID_EXT       |
                                    SRP_OPT_IOC_GUID     |
                                    SRP_OPT_DGID         |
@@ -2267,6 +2310,7 @@ static const match_table_t srp_opt_tokens = {
         { SRP_OPT_SG_TABLESIZE,         "sg_tablesize=%u"       },
         { SRP_OPT_COMP_VECTOR,          "comp_vector=%u"        },
         { SRP_OPT_TL_RETRY_COUNT,       "tl_retry_count=%u"     },
+        { SRP_OPT_QUEUE_SIZE,           "queue_size=%d"         },
         { SRP_OPT_ERR,                  NULL                    }
 };
 
@@ -2361,13 +2405,25 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
                         target->scsi_host->max_sectors = token;
                         break;
 
+                case SRP_OPT_QUEUE_SIZE:
+                        if (match_int(args, &token) || token < 1) {
+                                pr_warn("bad queue_size parameter '%s'\n", p);
+                                goto out;
+                        }
+                        target->scsi_host->can_queue = token;
+                        target->queue_size = token + SRP_RSP_SQ_SIZE +
+                                             SRP_TSK_MGMT_SQ_SIZE;
+                        if (!(opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
+                                target->scsi_host->cmd_per_lun = token;
+                        break;
+
                 case SRP_OPT_MAX_CMD_PER_LUN:
-                        if (match_int(args, &token)) {
+                        if (match_int(args, &token) || token < 1) {
                                 pr_warn("bad max cmd_per_lun parameter '%s'\n",
                                         p);
                                 goto out;
                         }
-                        target->scsi_host->cmd_per_lun = min(token, SRP_CMD_SQ_SIZE);
+                        target->scsi_host->cmd_per_lun = token;
                         break;
 
                 case SRP_OPT_IO_CLASS:
@@ -2455,6 +2511,12 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
                                 pr_warn("target creation request is missing parameter '%s'\n",
                                         srp_opt_tokens[i].pattern);
 
+        if (target->scsi_host->cmd_per_lun > target->scsi_host->can_queue
+            && (opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
+                pr_warn("cmd_per_lun = %d > queue_size = %d\n",
+                        target->scsi_host->cmd_per_lun,
+                        target->scsi_host->can_queue);
+
 out:
         kfree(options);
         return ret;
@@ -2493,11 +2555,14 @@ static ssize_t srp_create_target(struct device *dev,
         target->sg_tablesize    = indirect_sg_entries ? : cmd_sg_entries;
         target->allow_ext_sg    = allow_ext_sg;
         target->tl_retry_count  = 7;
+        target->queue_size      = SRP_DEFAULT_QUEUE_SIZE;
 
         ret = srp_parse_options(buf, target);
         if (ret)
                 goto err;
 
+        target->req_ring_size = target->queue_size - SRP_TSK_MGMT_SQ_SIZE;
+
         if (!srp_conn_unique(target->srp_host, target)) {
                 shost_printk(KERN_INFO, target->scsi_host,
                              PFX "Already connected to target port with id_ext=%016llx;ioc_guid=%016llx;initiator_ext=%016llx\n",
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 446b0452107b..575681063f38 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -57,14 +57,11 @@ enum {
         SRP_MAX_LUN             = 512,
         SRP_DEF_SG_TABLESIZE    = 12,
 
-        SRP_RQ_SHIFT            = 6,
-        SRP_RQ_SIZE             = 1 << SRP_RQ_SHIFT,
-
-        SRP_SQ_SIZE             = SRP_RQ_SIZE,
+        SRP_DEFAULT_QUEUE_SIZE  = 1 << 6,
         SRP_RSP_SQ_SIZE         = 1,
-        SRP_REQ_SQ_SIZE         = SRP_SQ_SIZE - SRP_RSP_SQ_SIZE,
         SRP_TSK_MGMT_SQ_SIZE    = 1,
-        SRP_CMD_SQ_SIZE         = SRP_REQ_SQ_SIZE - SRP_TSK_MGMT_SQ_SIZE,
+        SRP_DEFAULT_CMD_SQ_SIZE = SRP_DEFAULT_QUEUE_SIZE - SRP_RSP_SQ_SIZE -
+                                  SRP_TSK_MGMT_SQ_SIZE,
 
         SRP_TAG_NO_REQ          = ~0U,
         SRP_TAG_TSK_MGMT        = 1U << 31,
@@ -156,6 +153,8 @@ struct srp_target_port {
         char                    target_name[32];
         unsigned int            scsi_id;
         unsigned int            sg_tablesize;
+        int                     queue_size;
+        int                     req_ring_size;
         int                     comp_vector;
         int                     tl_retry_count;
 
@@ -173,9 +172,9 @@ struct srp_target_port {
 
         int                     zero_req_lim;
 
-        struct srp_iu          *tx_ring[SRP_SQ_SIZE];
-        struct srp_iu          *rx_ring[SRP_RQ_SIZE];
-        struct srp_request      req_ring[SRP_CMD_SQ_SIZE];
+        struct srp_iu          **tx_ring;
+        struct srp_iu          **rx_ring;
+        struct srp_request      *req_ring;
 
         struct work_struct      tl_err_work;
         struct work_struct      remove_work;