2 files changed, 25 insertions, 15 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 7f8f16bad753..b8b09a4f012a 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]);
 }
 
@@ -822,7 +822,7 @@ 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];
 
@@ -989,19 +989,19 @@ static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
 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;
+        s32 rsv = (req_type == SRP_REQ_TASK_MGMT) ? 0 : SRP_TSK_MGMT_SQ_SIZE;
 
         srp_send_completion(target->send_cq, target);
 
         if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
                 return NULL;
 
-        if (target->req_lim < min) {
+        if (target->req_lim <= rsv) {
                 ++target->zero_req_lim;
                 return NULL;
         }
 
-        return target->tx_ring[target->tx_head & SRP_SQ_SIZE];
+        return target->tx_ring[target->tx_head & SRP_SQ_MASK];
 }
 
 /*
@@ -1020,7 +1020,7 @@ static int __srp_post_send(struct srp_target_port *target,
         list.lkey   = target->srp_host->srp_dev->mr->lkey;
 
         wr.next       = NULL;
-        wr.wr_id      = target->tx_head & SRP_SQ_SIZE;
+        wr.wr_id      = target->tx_head & SRP_SQ_MASK;
         wr.sg_list    = &list;
         wr.num_sge    = 1;
         wr.opcode     = IB_WR_SEND;
@@ -1121,7 +1121,7 @@ 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 +1137,7 @@ 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;
         }
@@ -1626,9 +1626,9 @@ 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 +1813,7 @@ 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 +1891,7 @@ 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 +2159,9 @@ 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;
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 5a80eac6fdaa..7a959d5f2fa6 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -59,7 +59,14 @@ enum {
 
         SRP_RQ_SHIFT            = 6,
         SRP_RQ_SIZE             = 1 << SRP_RQ_SHIFT,
-        SRP_SQ_SIZE             = SRP_RQ_SIZE - 1,
+        SRP_RQ_MASK             = SRP_RQ_SIZE - 1,
+
+        SRP_SQ_SIZE             = SRP_RQ_SIZE,
+        SRP_SQ_MASK             = SRP_SQ_SIZE - 1,
+        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_TAG_TSK_MGMT        = 1 << (SRP_RQ_SHIFT + 1),
 
@@ -144,11 +151,11 @@ struct srp_target_port {
 
         unsigned                tx_head;
         unsigned                tx_tail;
-        struct srp_iu          *tx_ring[SRP_SQ_SIZE + 1];
+        struct srp_iu          *tx_ring[SRP_SQ_SIZE];
 
         struct list_head        free_reqs;
         struct list_head        req_queue;
-        struct srp_request      req_ring[SRP_SQ_SIZE];
+        struct srp_request      req_ring[SRP_CMD_SQ_SIZE];
 
         struct work_struct      work;