Here is a seventh version of the IPOIB_CM_NOSRQ patch.

Changes from V6:
1. Minor changes incorporating Sean Hefty's comments (changed
spin lock to an atomic and additional cleanups)

This patch has been tested with linux-2.6.22 derived from Roland's
for-2.6.23 git tree on ppc64 machines

Signed-off-by: Pradeep Satyanarayana <[EMAIL PROTECTED]>
---

--- a/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib.h 2007-05-30 14:56:25.000000000 -0400 +++ b/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib.h 2007-07-10 18:30:10.000000000 -0400
@@ -95,11 +95,16 @@ enum {
        IPOIB_MCAST_FLAG_ATTACHED = 3,
 };

+#define CM_PACKET_SIZE (1ul << 16)
 #define        IPOIB_OP_RECV   (1ul << 31)
 #ifdef CONFIG_INFINIBAND_IPOIB_CM
-#define        IPOIB_CM_OP_SRQ (1ul << 30)
+#define        IPOIB_CM_OP_RECV (1ul << 30)
+
+#define NOSRQ_INDEX_TABLE_SIZE 128
+#define NOSRQ_INDEX_MASK      (NOSRQ_INDEX_TABLE_SIZE -1)
+
 #else
-#define        IPOIB_CM_OP_SRQ (0)
+#define        IPOIB_CM_OP_RECV (0)
 #endif

 /* structs */
@@ -166,11 +171,14 @@ enum ipoib_cm_state {
 };

 struct ipoib_cm_rx {
-       struct ib_cm_id     *id;
-       struct ib_qp        *qp;
-       struct list_head     list;
-       struct net_device   *dev;
-       unsigned long        jiffies;
+       struct ib_cm_id         *id;
+       struct ib_qp            *qp;
+       struct ipoib_cm_rx_buf  *rx_ring; /* Used by NOSRQ only */
+       struct list_head         list;
+       struct net_device       *dev;
+       unsigned long            jiffies;
+       u32                      index; /* wr_ids are distinguished by index
+                                        * to identify the QP -NOSRQ only */
        enum ipoib_cm_state  state;
 };

@@ -215,6 +223,8 @@ struct ipoib_cm_dev_priv {
        struct ib_wc            ibwc[IPOIB_NUM_WC];
        struct ib_sge           rx_sge[IPOIB_CM_RX_SG];
        struct ib_recv_wr       rx_wr;
+       struct ipoib_cm_rx      **rx_index_table; /* See ipoib_cm_dev_init()
+                                                  *for usage of this element */
 };

 /*
@@ -564,10 +574,9 @@ static inline void ipoib_cm_skb_too_long
        dev_kfree_skb_any(skb);
 }

-static inline void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
+void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
 {
 }
-
 #endif

 #ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
--- a/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib_cm.c 2007-07-10 17:02:33.000000000 -0400 +++ b/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib_cm.c 2007-07-17 17:45:16.000000000 -0400
@@ -49,6 +49,17 @@ MODULE_PARM_DESC(cm_data_debug_level,

 #include "ipoib.h"

+int max_rc_qp = NOSRQ_INDEX_TABLE_SIZE;
+int max_recv_buf = 1024; /* Default is 1024 MB */
+
+module_param_named(nosrq_max_rc_qp, max_rc_qp, int, 0644);
+MODULE_PARM_DESC(nosrq_max_rc_qp, "Max number of NOSRQ RC QPs supported");
+
+module_param_named(max_receive_buffer, max_recv_buf, int, 0644);
+MODULE_PARM_DESC(max_receive_buffer, "Max Receive Buffer Size in MB");
+
+atomic_t current_rc_qp; /* Active number of RC QPs for NOSRQ */
+
 #define IPOIB_CM_IETF_ID 0x1000000000000000ULL

 #define IPOIB_CM_RX_UPDATE_TIME (256 * HZ)
@@ -81,20 +92,20 @@ static void ipoib_cm_dma_unmap_rx(struct
ib_dma_unmap_single(priv->ca, mapping[i + 1], PAGE_SIZE, DMA_FROM_DEVICE);
 }

-static int ipoib_cm_post_receive(struct net_device *dev, int id)
+static int post_receive_srq(struct net_device *dev, u64 id)
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct ib_recv_wr *bad_wr;
        int i, ret;

-       priv->cm.rx_wr.wr_id = id | IPOIB_CM_OP_SRQ;
+       priv->cm.rx_wr.wr_id = id | IPOIB_CM_OP_RECV;

        for (i = 0; i < IPOIB_CM_RX_SG; ++i)
                priv->cm.rx_sge[i].addr = priv->cm.srq_ring[id].mapping[i];

        ret = ib_post_srq_recv(priv->cm.srq, &priv->cm.rx_wr, &bad_wr);
        if (unlikely(ret)) {
-               ipoib_warn(priv, "post srq failed for buf %d (%d)\n", id, ret);
+               ipoib_warn(priv, "post srq failed for buf %ld (%d)\n", id, ret);
                ipoib_cm_dma_unmap_rx(priv, IPOIB_CM_RX_SG - 1,
                                      priv->cm.srq_ring[id].mapping);
                dev_kfree_skb_any(priv->cm.srq_ring[id].skb);
@@ -104,12 +115,47 @@ static int ipoib_cm_post_receive(struct
        return ret;
 }

-static struct sk_buff *ipoib_cm_alloc_rx_skb(struct net_device *dev, int id, int frags,
+static int post_receive_nosrq(struct net_device *dev, u64 id)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_recv_wr *bad_wr;
+       int i, ret;
+       u32 index;
+       u32 wr_id;
+       struct ipoib_cm_rx *rx_ptr;
+
+       index = id  & NOSRQ_INDEX_MASK ;
+       wr_id = id >> 32;
+
+       rx_ptr = priv->cm.rx_index_table[index];
+
+       priv->cm.rx_wr.wr_id = id | IPOIB_CM_OP_RECV;
+
+       for (i = 0; i < IPOIB_CM_RX_SG; ++i)
+               priv->cm.rx_sge[i].addr = rx_ptr->rx_ring[wr_id].mapping[i];
+
+       ret = ib_post_recv(rx_ptr->qp, &priv->cm.rx_wr, &bad_wr);
+       if (unlikely(ret)) {
+               ipoib_warn(priv, "post recv failed for buf %d (%d)\n",
+                          wr_id, ret);
+               ipoib_cm_dma_unmap_rx(priv, IPOIB_CM_RX_SG - 1,
+                                     rx_ptr->rx_ring[wr_id].mapping);
+               dev_kfree_skb_any(rx_ptr->rx_ring[wr_id].skb);
+               rx_ptr->rx_ring[wr_id].skb = NULL;
+       }
+
+       return ret;
+}
+
+static struct sk_buff *ipoib_cm_alloc_rx_skb(struct net_device *dev, u64 id,
+                                            int frags,
                                             u64 mapping[IPOIB_CM_RX_SG])
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct sk_buff *skb;
        int i;
+       struct ipoib_cm_rx *rx_ptr;
+       u32 index, wr_id;

        skb = dev_alloc_skb(IPOIB_CM_HEAD_SIZE + 12);
        if (unlikely(!skb))
@@ -141,7 +187,14 @@ static struct sk_buff *ipoib_cm_alloc_rx
                        goto partial_error;
        }

-       priv->cm.srq_ring[id].skb = skb;
+       if (priv->cm.srq)
+               priv->cm.srq_ring[id].skb = skb;
+       else {
+               index = id  & NOSRQ_INDEX_MASK ;
+               wr_id = id >> 32;
+               rx_ptr = priv->cm.rx_index_table[index];
+               rx_ptr->rx_ring[wr_id].skb = skb;
+       }
        return skb;

 partial_error:
@@ -198,16 +251,21 @@ static struct ib_qp *ipoib_cm_create_rx_
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
        struct ib_qp_init_attr attr = {
-               .event_handler = ipoib_cm_rx_event_handler,
                .send_cq = priv->cq, /* For drain WR */
                .recv_cq = priv->cq,
                .srq = priv->cm.srq,
                .cap.max_send_wr = 1, /* For drain WR */
+               .cap.max_recv_wr = ipoib_recvq_size + 1,
                .cap.max_send_sge = 1, /* FIXME: 0 Seems not to work */
                .sq_sig_type = IB_SIGNAL_ALL_WR,
                .qp_type = IB_QPT_RC,
                .qp_context = p,
        };
+       if (!priv->cm.srq) {
+               attr.cap.max_recv_sge = IPOIB_CM_RX_SG; 
+               attr.event_handler = NULL;
+       } else
+               attr.event_handler = ipoib_cm_rx_event_handler;
        return ib_create_qp(priv->pd, &attr);
 }

@@ -282,12 +340,129 @@ static int ipoib_cm_send_rep(struct net_
        rep.flow_control = 0;
        rep.rnr_retry_count = req->rnr_retry_count;
        rep.target_ack_delay = 20; /* FIXME */
-       rep.srq = 1;
        rep.qp_num = qp->qp_num;
        rep.starting_psn = psn;
+       rep.srq = !!priv->cm.srq;
        return ib_send_cm_rep(cm_id, &rep);
 }

+static void init_context_and_add_list(struct ib_cm_id *cm_id,
+                                   struct ipoib_cm_rx *p,
+                                   struct ipoib_dev_priv *priv)
+{
+       cm_id->context = p;
+       p->jiffies = jiffies;
+       spin_lock_irq(&priv->lock);
+       if (list_empty(&priv->cm.passive_ids))
+               queue_delayed_work(ipoib_workqueue,
+                                  &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
+       if (priv->cm.srq) {
+               /* Add this entry to passive ids list head, but do not re-add
+                * it if IB_EVENT_QP_LAST_WQE_REACHED has moved it to flush
+                * list.
+                */
+               if (p->state == IPOIB_CM_RX_LIVE)
+                       list_move(&p->list, &priv->cm.passive_ids);
+       }
+       spin_unlock_irq(&priv->lock);
+}
+
+static int allocate_and_post_rbuf_nosrq(struct ib_cm_id *cm_id,
+                                       struct ipoib_cm_rx *p, unsigned psn)
+{
+       struct net_device *dev = cm_id->context;
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       int ret;
+       u32 qp_num, index;
+       u64 i, recv_mem_used;
+
+       qp_num = p->qp->qp_num;
+
+       /* In the SRQ case there is a common rx buffer called the srq_ring.
+        * However, for the NOSRQ we create an rx_ring for every
+        * struct ipoib_cm_rx.
+        */
+       p->rx_ring = kzalloc(ipoib_recvq_size * sizeof *p->rx_ring, GFP_KERNEL);
+       if (!p->rx_ring) {
+               printk(KERN_WARNING "Failed to allocate rx_ring for 0x%x\n",
+                      qp_num);
+               return -ENOMEM;
+       }
+
+       spin_lock_irq(&priv->lock);
+       list_add(&p->list, &priv->cm.passive_ids);
+       spin_unlock_irq(&priv->lock);
+
+       init_context_and_add_list(cm_id, p, priv);
+       spin_lock_irq(&priv->lock);
+               
+       for (index = 0; index < max_rc_qp; index++)
+               if (priv->cm.rx_index_table[index] == NULL)
+                       break;
+
+       recv_mem_used = (u64)ipoib_recvq_size *
+                       (u64)atomic_inc_return(&current_rc_qp)
+                        * CM_PACKET_SIZE; /* packets are 64K */
+       if ((index == max_rc_qp) ||
+       ( recv_mem_used >= max_recv_buf * (1ul << 20))) {
+               spin_unlock_irq(&priv->lock);
+               ipoib_warn(priv, "NOSRQ has reached the configurable limit "
+                          "of either %d RC QPs or, max recv buf size of "
+                          "0x%x MB\n", max_rc_qp, max_recv_buf);
+
+               /* We send a REJ to the remote side indicating that we
+                * have no more free RC QPs and leave it to the remote side
+                * to take appropriate action. This should leave the
+                * current set of QPs unaffected and any subsequent REQs
+                * will be able to use RC QPs if they are available.
+                */
+               ib_send_cm_rej(cm_id, IB_CM_REJ_NO_QP, NULL, 0, NULL, 0);
+               ret = -EINVAL;
+               goto err_alloc_and_post;
+       }
+
+       priv->cm.rx_index_table[index] = p;
+       spin_unlock_irq(&priv->lock);
+
+       /* We will subsequently use this stored pointer while freeing
+        * resources in stale task
+        */
+       p->index = index;
+
+       ret = ipoib_cm_modify_rx_qp(dev, cm_id, p->qp, psn);
+       if (ret) {
+               ipoib_warn(priv, "ipoib_cm_modify_rx_qp() failed %d\n", ret);
+               ipoib_cm_dev_cleanup(dev);
+               goto err_alloc_and_post;
+       }
+
+       for (i = 0; i < ipoib_recvq_size; ++i) {
+               if (!ipoib_cm_alloc_rx_skb(dev, i << 32 | index,
+                                          IPOIB_CM_RX_SG - 1,
+                                          p->rx_ring[i].mapping)) {
+                       ipoib_warn(priv, "failed to allocate receive "
+                                  "buffer %ld\n", i);
+                       ipoib_cm_dev_cleanup(dev);
+                       ret = -ENOMEM;
+                       goto err_alloc_and_post;
+               }
+
+               if (post_receive_nosrq(dev, i << 32 | index)) {
+                       ipoib_warn(priv, "post_receive_nosrq "
+                                  "failed for  buf %ld\n", i);
+                       ipoib_cm_dev_cleanup(dev);
+                       ret = -EIO;
+                       goto err_alloc_and_post;
+               }
+       }
+
+       return 0;
+
+err_alloc_and_post:
+       kfree(p->rx_ring);
+       return ret;
+}
+
static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
 {
        struct net_device *dev = cm_id->context;
@@ -298,13 +473,13 @@ static int ipoib_cm_req_handler(struct i

        ipoib_dbg(priv, "REQ arrived\n");
        p = kzalloc(sizeof *p, GFP_KERNEL);
-       if (!p)
+       if (!p) {
+               printk(KERN_WARNING "Failed to allocate RX control block when "
+                      "REQ arrived\n");
                return -ENOMEM;
+       }
        p->dev = dev;
        p->id = cm_id;
-       cm_id->context = p;
-       p->state = IPOIB_CM_RX_LIVE;
-       p->jiffies = jiffies;
        INIT_LIST_HEAD(&p->list);

        p->qp = ipoib_cm_create_rx_qp(dev, p);
@@ -314,19 +489,20 @@ static int ipoib_cm_req_handler(struct i
        }

        psn = random32() & 0xffffff;
-       ret = ipoib_cm_modify_rx_qp(dev, cm_id, p->qp, psn);
-       if (ret)
-               goto err_modify;
+       if (!priv->cm.srq) {
+               if ((ret = allocate_and_post_rbuf_nosrq(cm_id, p, psn)))
+                       goto err_post_nosrq;
+       } else {
+               p->rx_ring = NULL;
+               ret = ipoib_cm_modify_rx_qp(dev, cm_id, p->qp, psn);
+               if (ret)
+                       goto err_modify;
+       }

-       spin_lock_irq(&priv->lock);
-       queue_delayed_work(ipoib_workqueue,
-                          &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
-       /* Add this entry to passive ids list head, but do not re-add it
-        * if IB_EVENT_QP_LAST_WQE_REACHED has moved it to flush list. */
-       p->jiffies = jiffies;
-       if (p->state == IPOIB_CM_RX_LIVE)
-               list_move(&p->list, &priv->cm.passive_ids);
-       spin_unlock_irq(&priv->lock);
+       if (priv->cm.srq) {
+               p->state = IPOIB_CM_RX_LIVE;
+               init_context_and_add_list(cm_id, p, priv);
+       }

        ret = ipoib_cm_send_rep(dev, cm_id, p->qp, &event->param.req_rcvd, psn);
        if (ret) {
@@ -336,6 +512,9 @@ static int ipoib_cm_req_handler(struct i
        }
        return 0;

+err_post_nosrq:
+       list_del_init(&p->list);
+       atomic_dec(&current_rc_qp);
 err_modify:
        ib_destroy_qp(p->qp);
 err_qp:
@@ -399,29 +578,60 @@ static void skb_put_frags(struct sk_buff
        }
 }

-void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
+static void timer_check_srq(struct ipoib_dev_priv *priv, struct ipoib_cm_rx *p)
+{
+       unsigned long flags;
+
+       if (p && time_after_eq(jiffies, p->jiffies + IPOIB_CM_RX_UPDATE_TIME)) {
+               spin_lock_irqsave(&priv->lock, flags);
+               p->jiffies = jiffies;
+               /* Move this entry to list head, but do
+                * not re-add it if it has been removed.
+                */
+               if (p->state == IPOIB_CM_RX_LIVE)
+                       list_move(&p->list, &priv->cm.passive_ids);
+               spin_unlock_irqrestore(&priv->lock, flags);
+       }
+}
+
+static void timer_check_nosrq(struct ipoib_dev_priv *priv, struct ipoib_cm_rx *p)
+{
+       unsigned long flags;
+
+       if (p && time_after_eq(jiffies, p->jiffies + IPOIB_CM_RX_UPDATE_TIME)) {
+               spin_lock_irqsave(&priv->lock, flags);
+               p->jiffies = jiffies;
+               /* Move this entry to list head, but do
+                * not re-add it if it has been removed. */
+               if (!list_empty(&p->list))       
+                       list_move(&p->list, &priv->cm.passive_ids);
+               spin_unlock_irqrestore(&priv->lock, flags);
+       }
+}
+
+void handle_rx_wc_srq(struct net_device *dev, struct ib_wc *wc)
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
-       unsigned int wr_id = wc->wr_id & ~IPOIB_CM_OP_SRQ;
+       u64 wr_id = wc->wr_id & ~IPOIB_CM_OP_RECV;
        struct sk_buff *skb, *newskb;
        struct ipoib_cm_rx *p;
        unsigned long flags;
        u64 mapping[IPOIB_CM_RX_SG];
-       int frags;
+       int frags, ret;

        ipoib_dbg_data(priv, "cm recv completion: id %d, status: %d\n",
                       wr_id, wc->status);

        if (unlikely(wr_id >= ipoib_recvq_size)) {
-               if (wr_id == (IPOIB_CM_RX_DRAIN_WRID & ~IPOIB_CM_OP_SRQ)) {
+               if (wr_id == (IPOIB_CM_RX_DRAIN_WRID & ~IPOIB_CM_OP_RECV)) {
                        spin_lock_irqsave(&priv->lock, flags);
                        list_splice_init(&priv->cm.rx_drain_list, 
&priv->cm.rx_reap_list);
                        ipoib_cm_start_rx_drain(priv);
                        queue_work(ipoib_workqueue, &priv->cm.rx_reap_task);
                        spin_unlock_irqrestore(&priv->lock, flags);
                } else
-                       ipoib_warn(priv, "cm recv completion event with wrid %d (> 
%d)\n",
-                                  wr_id, ipoib_recvq_size);
+                       ipoib_warn(priv, "cm recv completion event with wrid 0x%llx 
(> 0x%x)\n",
+                                  (unsigned long long)wr_id, ipoib_recvq_size);
                return;
        }

@@ -429,23 +639,15 @@ void ipoib_cm_handle_rx_wc(struct net_de

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                ipoib_dbg(priv, "cm recv error "
-                          "(status=%d, wrid=%d vend_err %x)\n",
-                          wc->status, wr_id, wc->vendor_err);
+                          "(status=%d, wrid=0x%llx vend_err %x)\n",
+                          wc->status, (unsigned long long)wr_id, 
wc->vendor_err);
                ++priv->stats.rx_dropped;
-               goto repost;
+               goto repost_srq;
        }

        if (!likely(wr_id & IPOIB_CM_RX_UPDATE_MASK)) {
                p = wc->qp->qp_context;
-               if (p && time_after_eq(jiffies, p->jiffies + 
IPOIB_CM_RX_UPDATE_TIME)) {
-                       spin_lock_irqsave(&priv->lock, flags);
-                       p->jiffies = jiffies;
-                       /* Move this entry to list head, but do not re-add it
-                        * if it has been moved out of list. */
-                       if (p->state == IPOIB_CM_RX_LIVE)
-                               list_move(&p->list, &priv->cm.passive_ids);
-                       spin_unlock_irqrestore(&priv->lock, flags);
-               }
+               timer_check_srq(priv, p);
        }

        frags = PAGE_ALIGN(wc->byte_len - min(wc->byte_len,
@@ -457,13 +659,112 @@ void ipoib_cm_handle_rx_wc(struct net_de
                 * If we can't allocate a new RX buffer, dump
                 * this packet and reuse the old buffer.
                 */
-               ipoib_dbg(priv, "failed to allocate receive buffer %d\n", 
wr_id);
+               ipoib_dbg(priv, "failed to allocate receive buffer %ld\n", 
wr_id);
+                ++priv->stats.rx_dropped;
+                goto repost_srq;
+        }
+
+       ipoib_cm_dma_unmap_rx(priv, frags,
+                             priv->cm.srq_ring[wr_id].mapping);
+       memcpy(priv->cm.srq_ring[wr_id].mapping, mapping,
+              (frags + 1) * sizeof *mapping);
+       ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
+                      wc->byte_len, wc->slid);
+
+       skb_put_frags(skb, IPOIB_CM_HEAD_SIZE, wc->byte_len, newskb);
+
+       skb->protocol = ((struct ipoib_header *) skb->data)->proto;
+       skb_reset_mac_header(skb);      
+       skb_pull(skb, IPOIB_ENCAP_LEN);
+
+       dev->last_rx = jiffies;
+       ++priv->stats.rx_packets;
+       priv->stats.rx_bytes += skb->len;
+
+       skb->dev = dev;
+       /* XXX get correct PACKET_ type here */
+       skb->pkt_type = PACKET_HOST;
+       netif_receive_skb(skb);
+
+repost_srq:
+       ret = post_receive_srq(dev, wr_id);
+
+       if (unlikely(ret))
+               ipoib_warn(priv, "post_receive_srq failed for buf %ld\n",
+                          wr_id);
+
+}
+
+static void handle_rx_wc_nosrq(struct net_device *dev, struct ib_wc *wc)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct sk_buff *skb, *newskb;
+       u64 mapping[IPOIB_CM_RX_SG], wr_id = wc->wr_id >> 32;
+       u32 index;
+       struct ipoib_cm_rx *rx_ptr;
+       int frags, ret;
+
+
+       ipoib_dbg_data(priv, "cm recv completion: id %d, status: %d\n",
+                      wr_id, wc->status);
+
+       if (unlikely(wr_id >= ipoib_recvq_size)) {
+               ipoib_warn(priv, "cm recv completion event with wrid 0x%llx (> 
%d)\n",
+                                  (unsigned long long)wr_id, ipoib_recvq_size);
+               return;
+       }
+
+       index = (wc->wr_id & ~IPOIB_CM_OP_RECV) & NOSRQ_INDEX_MASK ;
+
+       /* This is the only place where rx_ptr could be a NULL - could
+        * have just received a packet from a connection that has become
+        * stale and so is going away. We will simply drop the packet and
+        * let the hardware (it s IB_QPT_RC) handle the dropped packet.
+        * In the timer_check() function below, p->jiffies is updated and
+        * hence the connection will not be stale after that.
+        */
+       rx_ptr = priv->cm.rx_index_table[index];
+       if (unlikely(!rx_ptr)) {
+               ipoib_warn(priv, "Received packet from a connection "
+                          "that is going away. Hardware will handle it.\n");
+               return;
+       }
+
+       skb = rx_ptr->rx_ring[wr_id].skb;
+
+       if (unlikely(wc->status != IB_WC_SUCCESS)) {
+               ipoib_dbg(priv, "cm recv error "
+                          "(status=%d, wrid=%ld vend_err %x)\n",
+                          wc->status, wr_id, wc->vendor_err);
+               ++priv->stats.rx_dropped;
+               goto repost_nosrq;
+       }
+
+       if (!likely(wr_id & IPOIB_CM_RX_UPDATE_MASK)) {
+               /* There are no guarantees that wc->qp is not NULL for HCAs
+               * that do not support SRQ. */
+               timer_check_nosrq(priv, rx_ptr);
+       }
+
+       frags = PAGE_ALIGN(wc->byte_len - min(wc->byte_len,
+                                             (unsigned)IPOIB_CM_HEAD_SIZE)) / 
PAGE_SIZE;
+
+       newskb = ipoib_cm_alloc_rx_skb(dev, wr_id << 32 | index, frags,
+                                      mapping);
+       if (unlikely(!newskb)) {
+               /*
+                * If we can't allocate a new RX buffer, dump
+                * this packet and reuse the old buffer.
+                */
+               ipoib_dbg(priv, "failed to allocate receive buffer %ld\n", 
wr_id);
                ++priv->stats.rx_dropped;
-               goto repost;
+               goto repost_nosrq;
        }

-       ipoib_cm_dma_unmap_rx(priv, frags, priv->cm.srq_ring[wr_id].mapping);
- memcpy(priv->cm.srq_ring[wr_id].mapping, mapping, (frags + 1) * sizeof *mapping);
+       ipoib_cm_dma_unmap_rx(priv, frags,
+                             rx_ptr->rx_ring[wr_id].mapping);
+       memcpy(rx_ptr->rx_ring[wr_id].mapping, mapping,
+              (frags + 1) * sizeof *mapping);

        ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
                       wc->byte_len, wc->slid);
@@ -483,10 +784,22 @@ void ipoib_cm_handle_rx_wc(struct net_de
        skb->pkt_type = PACKET_HOST;
        netif_receive_skb(skb);

-repost:
-       if (unlikely(ipoib_cm_post_receive(dev, wr_id)))
-               ipoib_warn(priv, "ipoib_cm_post_receive failed "
-                          "for buf %d\n", wr_id);
+repost_nosrq:
+       ret = post_receive_nosrq(dev, wr_id << 32 | index);
+
+       if (unlikely(ret))
+               ipoib_warn(priv, "post_receive_nosrq failed for buf %ld\n",
+                          wr_id);
+}
+
+void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+
+       if (priv->cm.srq)
+               handle_rx_wc_srq(dev, wc);
+       else
+               handle_rx_wc_nosrq(dev, wc);
 }

 static inline int post_send(struct ipoib_dev_priv *priv,
@@ -678,6 +991,42 @@ err_cm:
        return ret;
 }

+static void free_resources_nosrq(struct ipoib_dev_priv *priv, struct ipoib_cm_rx *p)
+{
+       int i;
+
+       for(i = 0; i < ipoib_recvq_size; ++i)
+               if(p->rx_ring[i].skb) {
+                       ipoib_cm_dma_unmap_rx(priv,
+                                        IPOIB_CM_RX_SG - 1,
+                                        p->rx_ring[i].mapping);
+                       dev_kfree_skb_any(p->rx_ring[i].skb);
+                       p->rx_ring[i].skb = NULL;
+               }
+       kfree(p->rx_ring);
+}
+
+void dev_stop_nosrq(struct ipoib_dev_priv *priv)
+{
+       struct ipoib_cm_rx *p;
+
+       spin_lock_irq(&priv->lock);
+       while (!list_empty(&priv->cm.passive_ids)) {
+               p = list_entry(priv->cm.passive_ids.next, typeof(*p), list);
+               free_resources_nosrq(priv, p);
+               list_del(&p->list);
+               spin_unlock_irq(&priv->lock);
+               ib_destroy_cm_id(p->id);
+               ib_destroy_qp(p->qp);
+               atomic_dec(&current_rc_qp);
+               kfree(p);
+               spin_lock_irq(&priv->lock);
+       }
+       spin_unlock_irq(&priv->lock);
+
+       cancel_delayed_work(&priv->cm.stale_task);
+}
+
 void ipoib_cm_dev_stop(struct net_device *dev)
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
@@ -692,6 +1041,11 @@ void ipoib_cm_dev_stop(struct net_device
        ib_destroy_cm_id(priv->cm.id);
        priv->cm.id = NULL;

+       if (!priv->cm.srq) {
+               dev_stop_nosrq(priv);
+               return;
+       }
+
        spin_lock_irq(&priv->lock);
        while (!list_empty(&priv->cm.passive_ids)) {
                p = list_entry(priv->cm.passive_ids.next, typeof(*p), list);
@@ -737,6 +1091,7 @@ void ipoib_cm_dev_stop(struct net_device
                kfree(p);
        }

+
        cancel_delayed_work(&priv->cm.stale_task);
 }

@@ -815,7 +1170,9 @@ static struct ib_qp *ipoib_cm_create_tx_
        attr.recv_cq = priv->cq;
        attr.srq = priv->cm.srq;
        attr.cap.max_send_wr = ipoib_sendq_size;
+       attr.cap.max_recv_wr = 1;
        attr.cap.max_send_sge = 1;
+       attr.cap.max_recv_sge = 1;
        attr.sq_sig_type = IB_SIGNAL_ALL_WR;
        attr.qp_type = IB_QPT_RC;
        attr.send_cq = cq;
@@ -855,7 +1212,7 @@ static int ipoib_cm_send_req(struct net_
        req.retry_count               = 0; /* RFC draft warns against retries */
        req.rnr_retry_count           = 0; /* RFC draft warns against retries */
        req.max_cm_retries            = 15;
-       req.srq                       = 1;
+       req.srq                       = !!priv->cm.srq;
        return ib_send_cm_req(id, &req);
 }

@@ -1200,6 +1557,9 @@ static void ipoib_cm_rx_reap(struct work
        list_for_each_entry_safe(p, n, &list, list) {
                ib_destroy_cm_id(p->id);
                ib_destroy_qp(p->qp);
+               if (!priv->cm.srq) { 
+                       atomic_dec(&current_rc_qp);
+               }
                kfree(p);
        }
 }
@@ -1218,12 +1578,19 @@ static void ipoib_cm_stale_task(struct w
                p = list_entry(priv->cm.passive_ids.prev, typeof(*p), list);
                if (time_before_eq(jiffies, p->jiffies + IPOIB_CM_RX_TIMEOUT))
                        break;
-               list_move(&p->list, &priv->cm.rx_error_list);
-               p->state = IPOIB_CM_RX_ERROR;
-               spin_unlock_irq(&priv->lock);
-               ret = ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE);
-               if (ret)
-                       ipoib_warn(priv, "unable to move qp to error state: 
%d\n", ret);
+               if (!priv->cm.srq) {
+                       free_resources_nosrq(priv, p);
+                       list_del_init(&p->list);
+                       priv->cm.rx_index_table[p->index] = NULL;
+                       spin_unlock_irq(&priv->lock);
+               } else {
+                       list_move(&p->list, &priv->cm.rx_error_list);
+                       p->state = IPOIB_CM_RX_ERROR;
+                       spin_unlock_irq(&priv->lock);
+                       ret = ib_modify_qp(p->qp, &ipoib_cm_err_attr, 
IB_QP_STATE);
+                       if (ret)
+                               ipoib_warn(priv, "unable to move qp to error state: 
%d\n", ret);
+               }
                spin_lock_irq(&priv->lock);
        }

@@ -1277,16 +1644,40 @@ int ipoib_cm_add_mode_attr(struct net_de
        return device_create_file(&dev->dev, &dev_attr_mode);
 }

+static int create_srq(struct net_device *dev, struct ipoib_dev_priv *priv)
+{
+       struct ib_srq_init_attr srq_init_attr;
+       int ret;
+
+       srq_init_attr.attr.max_wr = ipoib_recvq_size;
+       srq_init_attr.attr.max_sge = IPOIB_CM_RX_SG;
+
+       priv->cm.srq = ib_create_srq(priv->pd, &srq_init_attr);
+       if (IS_ERR(priv->cm.srq)) {
+               ret = PTR_ERR(priv->cm.srq);
+               priv->cm.srq = NULL;
+               return ret;
+       }
+
+       priv->cm.srq_ring = kzalloc(ipoib_recvq_size *
+                                   sizeof *priv->cm.srq_ring,
+                                   GFP_KERNEL);
+       if (!priv->cm.srq_ring) {
+               printk(KERN_WARNING "%s: failed to allocate CM ring "
+                      "(%d entries)\n",
+                      priv->ca->name, ipoib_recvq_size);
+               ipoib_cm_dev_cleanup(dev);
+               return -ENOMEM;
+       }
+
+       return 0;
+}
+
 int ipoib_cm_dev_init(struct net_device *dev)
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
-       struct ib_srq_init_attr srq_init_attr = {
-               .attr = {
-                       .max_wr  = ipoib_recvq_size,
-                       .max_sge = IPOIB_CM_RX_SG
-               }
-       };
        int ret, i;
+       struct ib_device_attr attr;

        INIT_LIST_HEAD(&priv->cm.passive_ids);
        INIT_LIST_HEAD(&priv->cm.reap_list);
@@ -1303,20 +1694,32 @@ int ipoib_cm_dev_init(struct net_device

        skb_queue_head_init(&priv->cm.skb_queue);

-       priv->cm.srq = ib_create_srq(priv->pd, &srq_init_attr);
-       if (IS_ERR(priv->cm.srq)) {
-               ret = PTR_ERR(priv->cm.srq);
-               priv->cm.srq = NULL;
+       if ((ret = ib_query_device(priv->ca, &attr)))
                return ret;
-       }

-       priv->cm.srq_ring = kzalloc(ipoib_recvq_size * sizeof 
*priv->cm.srq_ring,
-                                   GFP_KERNEL);
-       if (!priv->cm.srq_ring) {
-               printk(KERN_WARNING "%s: failed to allocate CM ring (%d 
entries)\n",
-                      priv->ca->name, ipoib_recvq_size);
-               ipoib_cm_dev_cleanup(dev);
-               return -ENOMEM;
+       if (attr.max_srq) {
+               /* This device supports SRQ */
+               if ((ret = create_srq(dev, priv)))
+                       return ret;
+               priv->cm.rx_index_table = NULL;
+       } else {
+               priv->cm.srq = NULL;
+               priv->cm.srq_ring = NULL;
+
+               /* Every new REQ that arrives creates a struct ipoib_cm_rx.
+                * These structures form a link list starting with the
+                * passive_ids. For quick and easy access we maintain a table
+                * of pointers to struct ipoib_cm_rx called the rx_index_table
+                */
+               priv->cm.rx_index_table = kzalloc(NOSRQ_INDEX_TABLE_SIZE *
+                                        sizeof *priv->cm.rx_index_table,
+                                        GFP_KERNEL);
+               if (!priv->cm.rx_index_table) {
+                       printk(KERN_WARNING "Failed to allocate 
NOSRQ_INDEX_TABLE\n");
+                       return -ENOMEM;
+               }
+
+               atomic_set(&current_rc_qp, 0);
        }

        for (i = 0; i < IPOIB_CM_RX_SG; ++i)
@@ -1329,17 +1732,24 @@ int ipoib_cm_dev_init(struct net_device
        priv->cm.rx_wr.sg_list = priv->cm.rx_sge;
        priv->cm.rx_wr.num_sge = IPOIB_CM_RX_SG;

-       for (i = 0; i < ipoib_recvq_size; ++i) {
-               if (!ipoib_cm_alloc_rx_skb(dev, i, IPOIB_CM_RX_SG - 1,
+       /* One can post receive buffers even before the RX QP is created
+        * only in the SRQ case. Therefore for NOSRQ we skip the rest of init
+        * and do that in ipoib_cm_req_handler()
+        */
+
+       if (priv->cm.srq) {
+               for (i = 0; i < ipoib_recvq_size; ++i) {
+                       if (!ipoib_cm_alloc_rx_skb(dev, i, IPOIB_CM_RX_SG - 1,
                                           priv->cm.srq_ring[i].mapping)) {
-                       ipoib_warn(priv, "failed to allocate receive buffer 
%d\n", i);
-                       ipoib_cm_dev_cleanup(dev);
-                       return -ENOMEM;
-               }
-               if (ipoib_cm_post_receive(dev, i)) {
-                       ipoib_warn(priv, "ipoib_ib_post_receive failed for buf 
%d\n", i);
-                       ipoib_cm_dev_cleanup(dev);
-                       return -EIO;
+                               ipoib_warn(priv, "failed to allocate receive buffer 
%d\n", i);
+                               ipoib_cm_dev_cleanup(dev);
+                               return -ENOMEM;
+                       }
+                       if (post_receive_srq(dev, i)) {
+                               ipoib_warn(priv, "post_receive_srq failed for buf 
%d\n", i);
+                               ipoib_cm_dev_cleanup(dev);
+                               return -EIO;
+                       }
                }
        }

--- a/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib_ib.c 2007-05-30 14:56:25.000000000 -0400 +++ b/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib_ib.c 2007-07-10 18:30:10.000000000 -0400
@@ -299,7 +299,7 @@ int ipoib_poll(struct net_device *dev, i
                for (i = 0; i < n; ++i) {
                        struct ib_wc *wc = priv->ibwc + i;

-                       if (wc->wr_id & IPOIB_CM_OP_SRQ) {
+                       if (wc->wr_id & IPOIB_CM_OP_RECV) {
                                ++done;
                                --max;
                                ipoib_cm_handle_rx_wc(dev, wc);
@@ -557,7 +557,7 @@ void ipoib_drain_cq(struct net_device *d
        do {
                n = ib_poll_cq(priv->cq, IPOIB_NUM_WC, priv->ibwc);
                for (i = 0; i < n; ++i) {
-                       if (priv->ibwc[i].wr_id & IPOIB_CM_OP_SRQ)
+                       if (priv->ibwc[i].wr_id & IPOIB_CM_OP_RECV)
                                ipoib_cm_handle_rx_wc(dev, priv->ibwc + i);
                        else if (priv->ibwc[i].wr_id & IPOIB_OP_RECV)
                                ipoib_ib_handle_rx_wc(dev, priv->ibwc + i);
--- a/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib_verbs.c 2007-05-30 14:56:25.000000000 -0400 +++ b/linux-2.6.22/drivers/infiniband/ulp/ipoib/ipoib_verbs.c 2007-07-10 18:30:10.000000000 -0400
@@ -175,6 +175,15 @@ int ipoib_transport_dev_init(struct net_
        if (!ret)
                size += ipoib_recvq_size + 1 /* 1 extra for rx_drain_qp */;

+       /* We increase the size of the CQ in the NOSRQ case to prevent CQ
+        * overflow. Every new REQ creates a new RX QP and each QP has an
+        * RX ring associated with it. Therefore we could have
+        * NOSRQ_INDEX_TABLE_SIZE*ipoib_recvq_size + ipoib_sendq_size CQEs
+        * in a CQ.
+        */
+       if(!priv->cm.srq)
+               size += (NOSRQ_INDEX_TABLE_SIZE -1)* ipoib_recvq_size;
+
priv->cq = ib_create_cq(priv->ca, ipoib_ib_completion, NULL, dev, size, 0);
        if (IS_ERR(priv->cq)) {
                printk(KERN_WARNING "%s: failed to create CQ\n", ca->name);

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