1 files changed, 168 insertions, 68 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 7f8f16bad753..cfc1d65c4577 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -291,7 +291,7 @@ static void srp_free_target_ib(struct srp_target_port *target)
 
         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 + 1; ++i)
+        for (i = 0; i < SRP_SQ_SIZE; ++i)
                 srp_free_iu(target->srp_host, target->tx_ring[i]);
 }
 
@@ -811,6 +811,75 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
         return len;
 }
 
+/*
+ * Must be called with target->scsi_host->host_lock held to protect
+ * req_lim and tx_head.  Lock cannot be dropped between call here and
+ * call to __srp_post_send().
+ *
+ * Note:
+ * An upper limit for the number of allocated information units for each
+ * request type is:
+ * - SRP_IU_CMD: SRP_CMD_SQ_SIZE, since the SCSI mid-layer never queues
+ *   more than Scsi_Host.can_queue requests.
+ * - SRP_IU_TSK_MGMT: SRP_TSK_MGMT_SQ_SIZE.
+ * - SRP_IU_RSP: 1, since a conforming SRP target never sends more than
+ *   one unanswered SRP request to an initiator.
+ */
+static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target,
+                                      enum srp_iu_type iu_type)
+{
+        s32 rsv = (iu_type == SRP_IU_TSK_MGMT) ? 0 : SRP_TSK_MGMT_SQ_SIZE;
+        struct srp_iu *iu;
+
+        srp_send_completion(target->send_cq, target);
+
+        if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
+                return NULL;
+
+        /* Initiator responses to target requests do not consume credits */
+        if (target->req_lim <= rsv && iu_type != SRP_IU_RSP) {
+                ++target->zero_req_lim;
+                return NULL;
+        }
+
+        iu = target->tx_ring[target->tx_head & SRP_SQ_MASK];
+        iu->type = iu_type;
+        return iu;
+}
+
+/*
+ * Must be called with target->scsi_host->host_lock held to protect
+ * req_lim and tx_head.
+ */
+static int __srp_post_send(struct srp_target_port *target,
+                           struct srp_iu *iu, int len)
+{
+        struct ib_sge list;
+        struct ib_send_wr wr, *bad_wr;
+        int ret = 0;
+
+        list.addr   = iu->dma;
+        list.length = len;
+        list.lkey   = target->srp_host->srp_dev->mr->lkey;
+
+        wr.next       = NULL;
+        wr.wr_id      = target->tx_head & SRP_SQ_MASK;
+        wr.sg_list    = &list;
+        wr.num_sge    = 1;
+        wr.opcode     = IB_WR_SEND;
+        wr.send_flags = IB_SEND_SIGNALED;
+
+        ret = ib_post_send(target->qp, &wr, &bad_wr);
+
+        if (!ret) {
+                ++target->tx_head;
+                if (iu->type != SRP_IU_RSP)
+                        --target->req_lim;
+        }
+
+        return ret;
+}
+
 static int srp_post_recv(struct srp_target_port *target)
 {
         unsigned long flags;
@@ -822,7 +891,7 @@ static int srp_post_recv(struct srp_target_port *target)
 
         spin_lock_irqsave(target->scsi_host->host_lock, flags);
 
-        next     = target->rx_head & (SRP_RQ_SIZE - 1);
+        next     = target->rx_head & SRP_RQ_MASK;
         wr.wr_id = next;
         iu       = target->rx_ring[next];
 
@@ -896,6 +965,71 @@ static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
         spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
 }
 
+static int srp_response_common(struct srp_target_port *target, s32 req_delta,
+                               void *rsp, int len)
+{
+        struct ib_device *dev;
+        unsigned long flags;
+        struct srp_iu *iu;
+        int err = 1;
+
+        dev = target->srp_host->srp_dev->dev;
+
+        spin_lock_irqsave(target->scsi_host->host_lock, flags);
+        target->req_lim += req_delta;
+
+        iu = __srp_get_tx_iu(target, SRP_IU_RSP);
+        if (!iu) {
+                shost_printk(KERN_ERR, target->scsi_host, PFX
+                             "no IU available to send response\n");
+                goto out;
+        }
+
+        ib_dma_sync_single_for_cpu(dev, iu->dma, len, DMA_TO_DEVICE);
+        memcpy(iu->buf, rsp, len);
+        ib_dma_sync_single_for_device(dev, iu->dma, len, DMA_TO_DEVICE);
+
+        err = __srp_post_send(target, iu, len);
+        if (err)
+                shost_printk(KERN_ERR, target->scsi_host, PFX
+                             "unable to post response: %d\n", err);
+
+out:
+        spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+        return err;
+}
+
+static void srp_process_cred_req(struct srp_target_port *target,
+                                 struct srp_cred_req *req)
+{
+        struct srp_cred_rsp rsp = {
+                .opcode = SRP_CRED_RSP,
+                .tag = req->tag,
+        };
+        s32 delta = be32_to_cpu(req->req_lim_delta);
+
+        if (srp_response_common(target, delta, &rsp, sizeof rsp))
+                shost_printk(KERN_ERR, target->scsi_host, PFX
+                             "problems processing SRP_CRED_REQ\n");
+}
+
+static void srp_process_aer_req(struct srp_target_port *target,
+                                struct srp_aer_req *req)
+{
+        struct srp_aer_rsp rsp = {
+                .opcode = SRP_AER_RSP,
+                .tag = req->tag,
+        };
+        s32 delta = be32_to_cpu(req->req_lim_delta);
+
+        shost_printk(KERN_ERR, target->scsi_host, PFX
+                     "ignoring AER for LUN %llu\n", be64_to_cpu(req->lun));
+
+        if (srp_response_common(target, delta, &rsp, sizeof rsp))
+                shost_printk(KERN_ERR, target->scsi_host, PFX
+                             "problems processing SRP_AER_REQ\n");
+}
+
 static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
 {
         struct ib_device *dev;
@@ -923,6 +1057,14 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
                 srp_process_rsp(target, iu->buf);
                 break;
 
+        case SRP_CRED_REQ:
+                srp_process_cred_req(target, iu->buf);
+                break;
+
+        case SRP_AER_REQ:
+                srp_process_aer_req(target, iu->buf);
+                break;
+
         case SRP_T_LOGOUT:
                 /* XXX Handle target logout */
                 shost_printk(KERN_WARNING, target->scsi_host,
@@ -981,61 +1123,6 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
         }
 }
 
-/*
- * Must be called with target->scsi_host->host_lock held to protect
- * 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,
-                                        enum srp_request_type req_type)
-{
-        s32 min = (req_type == SRP_REQ_TASK_MGMT) ? 1 : 2;
-
-        srp_send_completion(target->send_cq, target);
-
-        if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
-                return NULL;
-
-        if (target->req_lim < min) {
-                ++target->zero_req_lim;
-                return NULL;
-        }
-
-        return target->tx_ring[target->tx_head & SRP_SQ_SIZE];
-}
-
-/*
- * Must be called with target->scsi_host->host_lock held to protect
- * req_lim and tx_head.
- */
-static int __srp_post_send(struct srp_target_port *target,
-                           struct srp_iu *iu, int len)
-{
-        struct ib_sge list;
-        struct ib_send_wr wr, *bad_wr;
-        int ret = 0;
-
-        list.addr   = iu->dma;
-        list.length = len;
-        list.lkey   = target->srp_host->srp_dev->mr->lkey;
-
-        wr.next       = NULL;
-        wr.wr_id      = target->tx_head & SRP_SQ_SIZE;
-        wr.sg_list    = &list;
-        wr.num_sge    = 1;
-        wr.opcode     = IB_WR_SEND;
-        wr.send_flags = IB_SEND_SIGNALED;
-
-        ret = ib_post_send(target->qp, &wr, &bad_wr);
-
-        if (!ret) {
-                ++target->tx_head;
-                --target->req_lim;
-        }
-
-        return ret;
-}
-
 static int srp_queuecommand(struct scsi_cmnd *scmnd,
                             void (*done)(struct scsi_cmnd *))
 {
@@ -1056,7 +1143,7 @@ static int srp_queuecommand(struct scsi_cmnd *scmnd,
                 return 0;
         }
 
-        iu = __srp_get_tx_iu(target, SRP_REQ_NORMAL);
+        iu = __srp_get_tx_iu(target, SRP_IU_CMD);
         if (!iu)
                 goto err;
 
@@ -1064,7 +1151,7 @@ static int srp_queuecommand(struct scsi_cmnd *scmnd,
         ib_dma_sync_single_for_cpu(dev, iu->dma, srp_max_iu_len,
                                    DMA_TO_DEVICE);
 
-        req = list_entry(target->free_reqs.next, struct srp_request, list);
+        req = list_first_entry(&target->free_reqs, struct srp_request, list);
 
         scmnd->scsi_done     = done;
         scmnd->result        = 0;
@@ -1121,7 +1208,7 @@ static int srp_alloc_iu_bufs(struct srp_target_port *target)
                         goto err;
         }
 
-        for (i = 0; i < SRP_SQ_SIZE + 1; ++i) {
+        for (i = 0; i < SRP_SQ_SIZE; ++i) {
                 target->tx_ring[i] = srp_alloc_iu(target->srp_host,
                                                   srp_max_iu_len,
                                                   GFP_KERNEL, DMA_TO_DEVICE);
@@ -1137,7 +1224,7 @@ err:
                 target->rx_ring[i] = NULL;
         }
 
-        for (i = 0; i < SRP_SQ_SIZE + 1; ++i) {
+        for (i = 0; i < SRP_SQ_SIZE; ++i) {
                 srp_free_iu(target->srp_host, target->tx_ring[i]);
                 target->tx_ring[i] = NULL;
         }
@@ -1252,8 +1339,13 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
                         target->max_ti_iu_len = be32_to_cpu(rsp->max_ti_iu_len);
                         target->req_lim       = be32_to_cpu(rsp->req_lim_delta);
 
-                        target->scsi_host->can_queue = min(target->req_lim,
-                                                           target->scsi_host->can_queue);
+                        /*
+                         * Reserve credits for task management so we don't
+                         * bounce requests back to the SCSI mid-layer.
+                         */
+                        target->scsi_host->can_queue
+                                = min(target->req_lim - SRP_TSK_MGMT_SQ_SIZE,
+                                      target->scsi_host->can_queue);
                 } else {
                         shost_printk(KERN_WARNING, target->scsi_host,
                                     PFX "Unhandled RSP opcode %#x\n", opcode);
@@ -1350,6 +1442,7 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
 static int srp_send_tsk_mgmt(struct srp_target_port *target,
                              struct srp_request *req, u8 func)
 {
+        struct ib_device *dev = target->srp_host->srp_dev->dev;
         struct srp_iu *iu;
         struct srp_tsk_mgmt *tsk_mgmt;
 
@@ -1363,10 +1456,12 @@ static int srp_send_tsk_mgmt(struct srp_target_port *target,
 
         init_completion(&req->done);
 
-        iu = __srp_get_tx_iu(target, SRP_REQ_TASK_MGMT);
+        iu = __srp_get_tx_iu(target, SRP_IU_TSK_MGMT);
         if (!iu)
                 goto out;
 
+        ib_dma_sync_single_for_cpu(dev, iu->dma, sizeof *tsk_mgmt,
+                                   DMA_TO_DEVICE);
         tsk_mgmt = iu->buf;
         memset(tsk_mgmt, 0, sizeof *tsk_mgmt);
 
@@ -1376,6 +1471,8 @@ static int srp_send_tsk_mgmt(struct srp_target_port *target,
         tsk_mgmt->tsk_mgmt_func = func;
         tsk_mgmt->task_tag      = req->index;
 
+        ib_dma_sync_single_for_device(dev, iu->dma, sizeof *tsk_mgmt,
+                                      DMA_TO_DEVICE);
         if (__srp_post_send(target, iu, sizeof *tsk_mgmt))
                 goto out;
 
@@ -1626,9 +1723,9 @@ static struct scsi_host_template srp_template = {
         .eh_abort_handler               = srp_abort,
         .eh_device_reset_handler        = srp_reset_device,
         .eh_host_reset_handler          = srp_reset_host,
-        .can_queue                      = SRP_SQ_SIZE,
+        .can_queue                      = SRP_CMD_SQ_SIZE,
         .this_id                        = -1,
-        .cmd_per_lun                    = SRP_SQ_SIZE,
+        .cmd_per_lun                    = SRP_CMD_SQ_SIZE,
         .use_clustering                 = ENABLE_CLUSTERING,
         .shost_attrs                    = srp_host_attrs
 };
@@ -1813,7 +1910,7 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
                                 printk(KERN_WARNING PFX "bad max cmd_per_lun parameter '%s'\n", p);
                                 goto out;
                         }
-                        target->scsi_host->cmd_per_lun = min(token, SRP_SQ_SIZE);
+                        target->scsi_host->cmd_per_lun = min(token, SRP_CMD_SQ_SIZE);
                         break;
 
                 case SRP_OPT_IO_CLASS:
@@ -1891,7 +1988,7 @@ static ssize_t srp_create_target(struct device *dev,
 
         INIT_LIST_HEAD(&target->free_reqs);
         INIT_LIST_HEAD(&target->req_queue);
-        for (i = 0; i < SRP_SQ_SIZE; ++i) {
+        for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
                 target->req_ring[i].index = i;
                 list_add_tail(&target->req_ring[i].list, &target->free_reqs);
         }
@@ -2159,6 +2256,9 @@ static int __init srp_init_module(void)
 {
         int ret;
 
+        BUILD_BUG_ON_NOT_POWER_OF_2(SRP_SQ_SIZE);
+        BUILD_BUG_ON_NOT_POWER_OF_2(SRP_RQ_SIZE);
+
         if (srp_sg_tablesize > 255) {
                 printk(KERN_WARNING PFX "Clamping srp_sg_tablesize to 255\n");
                 srp_sg_tablesize = 255;