1 files changed, 408 insertions, 274 deletions

diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
index 17fa80803ab0..71f373c421bc 100644
--- a/net/rds/ib_send.c
+++ b/net/rds/ib_send.c
@@ -36,11 +36,49 @@
 #include <linux/dmapool.h>
 
 #include "rds.h"
-#include "rdma.h"
 #include "ib.h"
 
-static void rds_ib_send_rdma_complete(struct rds_message *rm,
-                                      int wc_status)
+static char *rds_ib_wc_status_strings[] = {
+#define RDS_IB_WC_STATUS_STR(foo) \
+                [IB_WC_##foo] = __stringify(IB_WC_##foo)
+        RDS_IB_WC_STATUS_STR(SUCCESS),
+        RDS_IB_WC_STATUS_STR(LOC_LEN_ERR),
+        RDS_IB_WC_STATUS_STR(LOC_QP_OP_ERR),
+        RDS_IB_WC_STATUS_STR(LOC_EEC_OP_ERR),
+        RDS_IB_WC_STATUS_STR(LOC_PROT_ERR),
+        RDS_IB_WC_STATUS_STR(WR_FLUSH_ERR),
+        RDS_IB_WC_STATUS_STR(MW_BIND_ERR),
+        RDS_IB_WC_STATUS_STR(BAD_RESP_ERR),
+        RDS_IB_WC_STATUS_STR(LOC_ACCESS_ERR),
+        RDS_IB_WC_STATUS_STR(REM_INV_REQ_ERR),
+        RDS_IB_WC_STATUS_STR(REM_ACCESS_ERR),
+        RDS_IB_WC_STATUS_STR(REM_OP_ERR),
+        RDS_IB_WC_STATUS_STR(RETRY_EXC_ERR),
+        RDS_IB_WC_STATUS_STR(RNR_RETRY_EXC_ERR),
+        RDS_IB_WC_STATUS_STR(LOC_RDD_VIOL_ERR),
+        RDS_IB_WC_STATUS_STR(REM_INV_RD_REQ_ERR),
+        RDS_IB_WC_STATUS_STR(REM_ABORT_ERR),
+        RDS_IB_WC_STATUS_STR(INV_EECN_ERR),
+        RDS_IB_WC_STATUS_STR(INV_EEC_STATE_ERR),
+        RDS_IB_WC_STATUS_STR(FATAL_ERR),
+        RDS_IB_WC_STATUS_STR(RESP_TIMEOUT_ERR),
+        RDS_IB_WC_STATUS_STR(GENERAL_ERR),
+#undef RDS_IB_WC_STATUS_STR
+};
+
+char *rds_ib_wc_status_str(enum ib_wc_status status)
+{
+        return rds_str_array(rds_ib_wc_status_strings,
+                             ARRAY_SIZE(rds_ib_wc_status_strings), status);
+}
+
+/*
+ * Convert IB-specific error message to RDS error message and call core
+ * completion handler.
+ */
+static void rds_ib_send_complete(struct rds_message *rm,
+                                 int wc_status,
+                                 void (*complete)(struct rds_message *rm, int status))
 {
         int notify_status;
 
@@ -60,69 +98,125 @@ static void rds_ib_send_rdma_complete(struct rds_message *rm,
                 notify_status = RDS_RDMA_OTHER_ERROR;
                 break;
         }
-        rds_rdma_send_complete(rm, notify_status);
+        complete(rm, notify_status);
+}
+
+static void rds_ib_send_unmap_data(struct rds_ib_connection *ic,
+                                   struct rm_data_op *op,
+                                   int wc_status)
+{
+        if (op->op_nents)
+                ib_dma_unmap_sg(ic->i_cm_id->device,
+                                op->op_sg, op->op_nents,
+                                DMA_TO_DEVICE);
 }
 
 static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic,
-                                   struct rds_rdma_op *op)
+                                   struct rm_rdma_op *op,
+                                   int wc_status)
 {
-        if (op->r_mapped) {
+        if (op->op_mapped) {
                 ib_dma_unmap_sg(ic->i_cm_id->device,
-                        op->r_sg, op->r_nents,
-                        op->r_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
-                op->r_mapped = 0;
+                                op->op_sg, op->op_nents,
+                                op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+                op->op_mapped = 0;
         }
+
+        /* If the user asked for a completion notification on this
+         * message, we can implement three different semantics:
+         *  1.  Notify when we received the ACK on the RDS message
+         *      that was queued with the RDMA. This provides reliable
+         *      notification of RDMA status at the expense of a one-way
+         *      packet delay.
+         *  2.  Notify when the IB stack gives us the completion event for
+         *      the RDMA operation.
+         *  3.  Notify when the IB stack gives us the completion event for
+         *      the accompanying RDS messages.
+         * Here, we implement approach #3. To implement approach #2,
+         * we would need to take an event for the rdma WR. To implement #1,
+         * don't call rds_rdma_send_complete at all, and fall back to the notify
+         * handling in the ACK processing code.
+         *
+         * Note: There's no need to explicitly sync any RDMA buffers using
+         * ib_dma_sync_sg_for_cpu - the completion for the RDMA
+         * operation itself unmapped the RDMA buffers, which takes care
+         * of synching.
+         */
+        rds_ib_send_complete(container_of(op, struct rds_message, rdma),
+                             wc_status, rds_rdma_send_complete);
+
+        if (op->op_write)
+                rds_stats_add(s_send_rdma_bytes, op->op_bytes);
+        else
+                rds_stats_add(s_recv_rdma_bytes, op->op_bytes);
 }
 
-static void rds_ib_send_unmap_rm(struct rds_ib_connection *ic,
-                          struct rds_ib_send_work *send,
-                          int wc_status)
+static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic,
+                                     struct rm_atomic_op *op,
+                                     int wc_status)
 {
-        struct rds_message *rm = send->s_rm;
-
-        rdsdebug("ic %p send %p rm %p\n", ic, send, rm);
-
-        ib_dma_unmap_sg(ic->i_cm_id->device,
-                     rm->m_sg, rm->m_nents,
-                     DMA_TO_DEVICE);
-
-        if (rm->m_rdma_op != NULL) {
-                rds_ib_send_unmap_rdma(ic, rm->m_rdma_op);
-
-                /* If the user asked for a completion notification on this
-                 * message, we can implement three different semantics:
-                 *  1.  Notify when we received the ACK on the RDS message
-                 *      that was queued with the RDMA. This provides reliable
-                 *      notification of RDMA status at the expense of a one-way
-                 *      packet delay.
-                 *  2.  Notify when the IB stack gives us the completion event for
-                 *      the RDMA operation.
-                 *  3.  Notify when the IB stack gives us the completion event for
-                 *      the accompanying RDS messages.
-                 * Here, we implement approach #3. To implement approach #2,
-                 * call rds_rdma_send_complete from the cq_handler. To implement #1,
-                 * don't call rds_rdma_send_complete at all, and fall back to the notify
-                 * handling in the ACK processing code.
-                 *
-                 * Note: There's no need to explicitly sync any RDMA buffers using
-                 * ib_dma_sync_sg_for_cpu - the completion for the RDMA
-                 * operation itself unmapped the RDMA buffers, which takes care
-                 * of synching.
-                 */
-                rds_ib_send_rdma_complete(rm, wc_status);
+        /* unmap atomic recvbuf */
+        if (op->op_mapped) {
+                ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1,
+                                DMA_FROM_DEVICE);
+                op->op_mapped = 0;
+        }
 
-                if (rm->m_rdma_op->r_write)
-                        rds_stats_add(s_send_rdma_bytes, rm->m_rdma_op->r_bytes);
-                else
-                        rds_stats_add(s_recv_rdma_bytes, rm->m_rdma_op->r_bytes);
+        rds_ib_send_complete(container_of(op, struct rds_message, atomic),
+                             wc_status, rds_atomic_send_complete);
+
+        if (op->op_type == RDS_ATOMIC_TYPE_CSWP)
+                rds_ib_stats_inc(s_ib_atomic_cswp);
+        else
+                rds_ib_stats_inc(s_ib_atomic_fadd);
+}
+
+/*
+ * Unmap the resources associated with a struct send_work.
+ *
+ * Returns the rm for no good reason other than it is unobtainable
+ * other than by switching on wr.opcode, currently, and the caller,
+ * the event handler, needs it.
+ */
+static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic,
+                                                struct rds_ib_send_work *send,
+                                                int wc_status)
+{
+        struct rds_message *rm = NULL;
+
+        /* In the error case, wc.opcode sometimes contains garbage */
+        switch (send->s_wr.opcode) {
+        case IB_WR_SEND:
+                if (send->s_op) {
+                        rm = container_of(send->s_op, struct rds_message, data);
+                        rds_ib_send_unmap_data(ic, send->s_op, wc_status);
+                }
+                break;
+        case IB_WR_RDMA_WRITE:
+        case IB_WR_RDMA_READ:
+                if (send->s_op) {
+                        rm = container_of(send->s_op, struct rds_message, rdma);
+                        rds_ib_send_unmap_rdma(ic, send->s_op, wc_status);
+                }
+                break;
+        case IB_WR_ATOMIC_FETCH_AND_ADD:
+        case IB_WR_ATOMIC_CMP_AND_SWP:
+                if (send->s_op) {
+                        rm = container_of(send->s_op, struct rds_message, atomic);
+                        rds_ib_send_unmap_atomic(ic, send->s_op, wc_status);
+                }
+                break;
+        default:
+                if (printk_ratelimit())
+                        printk(KERN_NOTICE
+                               "RDS/IB: %s: unexpected opcode 0x%x in WR!\n",
+                               __func__, send->s_wr.opcode);
+                break;
         }
 
-        /* If anyone waited for this message to get flushed out, wake
-         * them up now */
-        rds_message_unmapped(rm);
+        send->s_wr.opcode = 0xdead;
 
-        rds_message_put(rm);
-        send->s_rm = NULL;
+        return rm;
 }
 
 void rds_ib_send_init_ring(struct rds_ib_connection *ic)
@@ -133,23 +227,18 @@ void rds_ib_send_init_ring(struct rds_ib_connection *ic)
         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
                 struct ib_sge *sge;
 
-                send->s_rm = NULL;
                 send->s_op = NULL;
 
                 send->s_wr.wr_id = i;
                 send->s_wr.sg_list = send->s_sge;
-                send->s_wr.num_sge = 1;
-                send->s_wr.opcode = IB_WR_SEND;
-                send->s_wr.send_flags = 0;
                 send->s_wr.ex.imm_data = 0;
 
-                sge = rds_ib_data_sge(ic, send->s_sge);
-                sge->lkey = ic->i_mr->lkey;
-
-                sge = rds_ib_header_sge(ic, send->s_sge);
+                sge = &send->s_sge[0];
                 sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header));
                 sge->length = sizeof(struct rds_header);
                 sge->lkey = ic->i_mr->lkey;
+
+                send->s_sge[1].lkey = ic->i_mr->lkey;
         }
 }
 
@@ -159,16 +248,24 @@ void rds_ib_send_clear_ring(struct rds_ib_connection *ic)
         u32 i;
 
         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
-                if (send->s_wr.opcode == 0xdead)
-                        continue;
-                if (send->s_rm)
-                        rds_ib_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR);
-                if (send->s_op)
-                        rds_ib_send_unmap_rdma(ic, send->s_op);
+                if (send->s_op && send->s_wr.opcode != 0xdead)
+                        rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR);
         }
 }
 
 /*
+ * The only fast path caller always has a non-zero nr, so we don't
+ * bother testing nr before performing the atomic sub.
+ */
+static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr)
+{
+        if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) &&
+            waitqueue_active(&rds_ib_ring_empty_wait))
+                wake_up(&rds_ib_ring_empty_wait);
+        BUG_ON(atomic_read(&ic->i_signaled_sends) < 0);
+}
+
+/*
  * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
  * operations performed in the send path.  As the sender allocs and potentially
  * unallocs the next free entry in the ring it doesn't alter which is
@@ -178,12 +275,14 @@ void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
 {
         struct rds_connection *conn = context;
         struct rds_ib_connection *ic = conn->c_transport_data;
+        struct rds_message *rm = NULL;
         struct ib_wc wc;
         struct rds_ib_send_work *send;
         u32 completed;
         u32 oldest;
         u32 i = 0;
         int ret;
+        int nr_sig = 0;
 
         rdsdebug("cq %p conn %p\n", cq, conn);
         rds_ib_stats_inc(s_ib_tx_cq_call);
@@ -192,8 +291,9 @@ void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
                 rdsdebug("ib_req_notify_cq send failed: %d\n", ret);
 
         while (ib_poll_cq(cq, 1, &wc) > 0) {
-                rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
-                         (unsigned long long)wc.wr_id, wc.status, wc.byte_len,
+                rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
+                         (unsigned long long)wc.wr_id, wc.status,
+                         rds_ib_wc_status_str(wc.status), wc.byte_len,
                          be32_to_cpu(wc.ex.imm_data));
                 rds_ib_stats_inc(s_ib_tx_cq_event);
 
@@ -210,51 +310,30 @@ void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
 
                 for (i = 0; i < completed; i++) {
                         send = &ic->i_sends[oldest];
+                        if (send->s_wr.send_flags & IB_SEND_SIGNALED)
+                                nr_sig++;
 
-                        /* In the error case, wc.opcode sometimes contains garbage */
-                        switch (send->s_wr.opcode) {
-                        case IB_WR_SEND:
-                                if (send->s_rm)
-                                        rds_ib_send_unmap_rm(ic, send, wc.status);
-                                break;
-                        case IB_WR_RDMA_WRITE:
-                        case IB_WR_RDMA_READ:
-                                /* Nothing to be done - the SG list will be unmapped
-                                 * when the SEND completes. */
-                                break;
-                        default:
-                                if (printk_ratelimit())
-                                        printk(KERN_NOTICE
-                                                "RDS/IB: %s: unexpected opcode 0x%x in WR!\n",
-                                                __func__, send->s_wr.opcode);
-                                break;
-                        }
+                        rm = rds_ib_send_unmap_op(ic, send, wc.status);
 
-                        send->s_wr.opcode = 0xdead;
-                        send->s_wr.num_sge = 1;
                         if (send->s_queued + HZ/2 < jiffies)
                                 rds_ib_stats_inc(s_ib_tx_stalled);
 
-                        /* If a RDMA operation produced an error, signal this right
-                         * away. If we don't, the subsequent SEND that goes with this
-                         * RDMA will be canceled with ERR_WFLUSH, and the application
-                         * never learn that the RDMA failed. */
-                        if (unlikely(wc.status == IB_WC_REM_ACCESS_ERR && send->s_op)) {
-                                struct rds_message *rm;
-
-                                rm = rds_send_get_message(conn, send->s_op);
-                                if (rm) {
-                                        if (rm->m_rdma_op)
-                                                rds_ib_send_unmap_rdma(ic, rm->m_rdma_op);
-                                        rds_ib_send_rdma_complete(rm, wc.status);
-                                        rds_message_put(rm);
+                        if (send->s_op) {
+                                if (send->s_op == rm->m_final_op) {
+                                        /* If anyone waited for this message to get flushed out, wake
+                                         * them up now */
+                                        rds_message_unmapped(rm);
                                 }
+                                rds_message_put(rm);
+                                send->s_op = NULL;
                         }
 
                         oldest = (oldest + 1) % ic->i_send_ring.w_nr;
                 }
 
                 rds_ib_ring_free(&ic->i_send_ring, completed);
+                rds_ib_sub_signaled(ic, nr_sig);
+                nr_sig = 0;
 
                 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
                     test_bit(0, &conn->c_map_queued))
@@ -262,10 +341,10 @@ void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
 
                 /* We expect errors as the qp is drained during shutdown */
                 if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) {
-                        rds_ib_conn_error(conn,
-                                "send completion on %pI4 "
-                                "had status %u, disconnecting and reconnecting\n",
-                                &conn->c_faddr, wc.status);
+                        rds_ib_conn_error(conn, "send completion on %pI4 had status "
+                                          "%u (%s), disconnecting and reconnecting\n",
+                                          &conn->c_faddr, wc.status,
+                                          rds_ib_wc_status_str(wc.status));
                 }
         }
 }
@@ -294,7 +373,7 @@ void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
  * credits (see rds_ib_send_add_credits below).
  *
  * The RDS send code is essentially single-threaded; rds_send_xmit
- * grabs c_send_lock to ensure exclusive access to the send ring.
+ * sets RDS_IN_XMIT to ensure exclusive access to the send ring.
  * However, the ACK sending code is independent and can race with
  * message SENDs.
  *
@@ -413,40 +492,21 @@ void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted)
                 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
 }
 
-static inline void
-rds_ib_xmit_populate_wr(struct rds_ib_connection *ic,
-                struct rds_ib_send_work *send, unsigned int pos,
-                unsigned long buffer, unsigned int length,
-                int send_flags)
+static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic,
+                                             struct rds_ib_send_work *send,
+                                             bool notify)
 {
-        struct ib_sge *sge;
-
-        WARN_ON(pos != send - ic->i_sends);
-
-        send->s_wr.send_flags = send_flags;
-        send->s_wr.opcode = IB_WR_SEND;
-        send->s_wr.num_sge = 2;
-        send->s_wr.next = NULL;
-        send->s_queued = jiffies;
-        send->s_op = NULL;
-
-        if (length != 0) {
-                sge = rds_ib_data_sge(ic, send->s_sge);
-                sge->addr = buffer;
-                sge->length = length;
-                sge->lkey = ic->i_mr->lkey;
-
-                sge = rds_ib_header_sge(ic, send->s_sge);
-        } else {
-                /* We're sending a packet with no payload. There is only
-                 * one SGE */
-                send->s_wr.num_sge = 1;
-                sge = &send->s_sge[0];
+        /*
+         * We want to delay signaling completions just enough to get
+         * the batching benefits but not so much that we create dead time
+         * on the wire.
+         */
+        if (ic->i_unsignaled_wrs-- == 0 || notify) {
+                ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
+                send->s_wr.send_flags |= IB_SEND_SIGNALED;
+                return 1;
         }
-
-        sge->addr = ic->i_send_hdrs_dma + (pos * sizeof(struct rds_header));
-        sge->length = sizeof(struct rds_header);
-        sge->lkey = ic->i_mr->lkey;
+        return 0;
 }
 
 /*
@@ -475,13 +535,14 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
         u32 pos;
         u32 i;
         u32 work_alloc;
-        u32 credit_alloc;
+        u32 credit_alloc = 0;
         u32 posted;
         u32 adv_credits = 0;
         int send_flags = 0;
-        int sent;
+        int bytes_sent = 0;
         int ret;
         int flow_controlled = 0;
+        int nr_sig = 0;
 
         BUG_ON(off % RDS_FRAG_SIZE);
         BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
@@ -507,14 +568,13 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
                 goto out;
         }
 
-        credit_alloc = work_alloc;
         if (ic->i_flowctl) {
                 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT);
                 adv_credits += posted;
                 if (credit_alloc < work_alloc) {
                         rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
                         work_alloc = credit_alloc;
-                        flow_controlled++;
+                        flow_controlled = 1;
                 }
                 if (work_alloc == 0) {
                         set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
@@ -525,31 +585,25 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
         }
 
         /* map the message the first time we see it */
-        if (ic->i_rm == NULL) {
-                /*
-                printk(KERN_NOTICE "rds_ib_xmit prep msg dport=%u flags=0x%x len=%d\n",
-                                be16_to_cpu(rm->m_inc.i_hdr.h_dport),
-                                rm->m_inc.i_hdr.h_flags,
-                                be32_to_cpu(rm->m_inc.i_hdr.h_len));
-                   */
-                if (rm->m_nents) {
-                        rm->m_count = ib_dma_map_sg(dev,
-                                         rm->m_sg, rm->m_nents, DMA_TO_DEVICE);
-                        rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->m_count);
-                        if (rm->m_count == 0) {
+        if (!ic->i_data_op) {
+                if (rm->data.op_nents) {
+                        rm->data.op_count = ib_dma_map_sg(dev,
+                                                          rm->data.op_sg,
+                                                          rm->data.op_nents,
+                                                          DMA_TO_DEVICE);
+                        rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count);
+                        if (rm->data.op_count == 0) {
                                 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
                                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
                                 ret = -ENOMEM; /* XXX ? */
                                 goto out;
                         }
                 } else {
-                        rm->m_count = 0;
+                        rm->data.op_count = 0;
                 }
 
-                ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
-                ic->i_unsignaled_bytes = rds_ib_sysctl_max_unsig_bytes;
                 rds_message_addref(rm);
-                ic->i_rm = rm;
+                ic->i_data_op = &rm->data;
 
                 /* Finalize the header */
                 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags))
@@ -559,10 +613,10 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
 
                 /* If it has a RDMA op, tell the peer we did it. This is
                  * used by the peer to release use-once RDMA MRs. */
-                if (rm->m_rdma_op) {
+                if (rm->rdma.op_active) {
                         struct rds_ext_header_rdma ext_hdr;
 
-                        ext_hdr.h_rdma_rkey = cpu_to_be32(rm->m_rdma_op->r_key);
+                        ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
                         rds_message_add_extension(&rm->m_inc.i_hdr,
                                         RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
                 }
@@ -582,99 +636,77 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
                 /*
                  * Update adv_credits since we reset the ACK_REQUIRED bit.
                  */
-                rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
-                adv_credits += posted;
-                BUG_ON(adv_credits > 255);
+                if (ic->i_flowctl) {
+                        rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
+                        adv_credits += posted;
+                        BUG_ON(adv_credits > 255);
+                }
         }
 
-        send = &ic->i_sends[pos];
-        first = send;
-        prev = NULL;
-        scat = &rm->m_sg[sg];
-        sent = 0;
-        i = 0;
-
         /* Sometimes you want to put a fence between an RDMA
          * READ and the following SEND.
          * We could either do this all the time
          * or when requested by the user. Right now, we let
          * the application choose.
          */
-        if (rm->m_rdma_op && rm->m_rdma_op->r_fence)
+        if (rm->rdma.op_active && rm->rdma.op_fence)
                 send_flags = IB_SEND_FENCE;
 
-        /*
-         * We could be copying the header into the unused tail of the page.
-         * That would need to be changed in the future when those pages might
-         * be mapped userspace pages or page cache pages.  So instead we always
-         * use a second sge and our long-lived ring of mapped headers.  We send
-         * the header after the data so that the data payload can be aligned on
-         * the receiver.
-         */
+        /* Each frag gets a header. Msgs may be 0 bytes */
+        send = &ic->i_sends[pos];
+        first = send;
+        prev = NULL;
+        scat = &ic->i_data_op->op_sg[sg];
+        i = 0;
+        do {
+                unsigned int len = 0;
 
-        /* handle a 0-len message */
-        if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) {
-                rds_ib_xmit_populate_wr(ic, send, pos, 0, 0, send_flags);
-                goto add_header;
-        }
+                /* Set up the header */
+                send->s_wr.send_flags = send_flags;
+                send->s_wr.opcode = IB_WR_SEND;
+                send->s_wr.num_sge = 1;
+                send->s_wr.next = NULL;
+                send->s_queued = jiffies;
+                send->s_op = NULL;
 
-        /* if there's data reference it with a chain of work reqs */
-        for (; i < work_alloc && scat != &rm->m_sg[rm->m_count]; i++) {
-                unsigned int len;
+                send->s_sge[0].addr = ic->i_send_hdrs_dma
+                        + (pos * sizeof(struct rds_header));
+                send->s_sge[0].length = sizeof(struct rds_header);
 
-                send = &ic->i_sends[pos];
+                memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header));
 
-                len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off);
-                rds_ib_xmit_populate_wr(ic, send, pos,
-                                ib_sg_dma_address(dev, scat) + off, len,
-                                send_flags);
+                /* Set up the data, if present */
+                if (i < work_alloc
+                    && scat != &rm->data.op_sg[rm->data.op_count]) {
+                        len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off);
+                        send->s_wr.num_sge = 2;
 
-                /*
-                 * We want to delay signaling completions just enough to get
-                 * the batching benefits but not so much that we create dead time
-                 * on the wire.
-                 */
-                if (ic->i_unsignaled_wrs-- == 0) {
-                        ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
-                        send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
-                }
+                        send->s_sge[1].addr = ib_sg_dma_address(dev, scat) + off;
+                        send->s_sge[1].length = len;
 
-                ic->i_unsignaled_bytes -= len;
-                if (ic->i_unsignaled_bytes <= 0) {
-                        ic->i_unsignaled_bytes = rds_ib_sysctl_max_unsig_bytes;
-                        send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
+                        bytes_sent += len;
+                        off += len;
+                        if (off == ib_sg_dma_len(dev, scat)) {
+                                scat++;
+                                off = 0;
+                        }
                 }
 
+                rds_ib_set_wr_signal_state(ic, send, 0);
+
                 /*
                  * Always signal the last one if we're stopping due to flow control.
                  */
-                if (flow_controlled && i == (work_alloc-1))
+                if (ic->i_flowctl && flow_controlled && i == (work_alloc-1))
                         send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
 
+                if (send->s_wr.send_flags & IB_SEND_SIGNALED)
+                        nr_sig++;
+
                 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
                          &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
 
-                sent += len;
-                off += len;
-                if (off == ib_sg_dma_len(dev, scat)) {
-                        scat++;
-                        off = 0;
-                }
-
-add_header:
-                /* Tack on the header after the data. The header SGE should already
-                 * have been set up to point to the right header buffer. */
-                memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header));
-
-                if (0) {
-                        struct rds_header *hdr = &ic->i_send_hdrs[pos];
-
-                        printk(KERN_NOTICE "send WR dport=%u flags=0x%x len=%d\n",
-                                be16_to_cpu(hdr->h_dport),
-                                hdr->h_flags,
-                                be32_to_cpu(hdr->h_len));
-                }
-                if (adv_credits) {
+                if (ic->i_flowctl && adv_credits) {
                         struct rds_header *hdr = &ic->i_send_hdrs[pos];
 
                         /* add credit and redo the header checksum */
@@ -689,20 +721,25 @@ add_header:
                 prev = send;
 
                 pos = (pos + 1) % ic->i_send_ring.w_nr;
-        }
+                send = &ic->i_sends[pos];
+                i++;
+
+        } while (i < work_alloc
+                 && scat != &rm->data.op_sg[rm->data.op_count]);
 
         /* Account the RDS header in the number of bytes we sent, but just once.
          * The caller has no concept of fragmentation. */
         if (hdr_off == 0)
-                sent += sizeof(struct rds_header);
+                bytes_sent += sizeof(struct rds_header);
 
         /* if we finished the message then send completion owns it */
-        if (scat == &rm->m_sg[rm->m_count]) {
-                prev->s_rm = ic->i_rm;
-                prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
-                ic->i_rm = NULL;
+        if (scat == &rm->data.op_sg[rm->data.op_count]) {
+                prev->s_op = ic->i_data_op;
+                prev->s_wr.send_flags |= IB_SEND_SOLICITED;
+                ic->i_data_op = NULL;
         }
 
+        /* Put back wrs & credits we didn't use */
         if (i < work_alloc) {
                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
                 work_alloc = i;
@@ -710,6 +747,9 @@ add_header:
         if (ic->i_flowctl && i < credit_alloc)
                 rds_ib_send_add_credits(conn, credit_alloc - i);
 
+        if (nr_sig)
+                atomic_add(nr_sig, &ic->i_signaled_sends);
+
         /* XXX need to worry about failed_wr and partial sends. */
         failed_wr = &first->s_wr;
         ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
@@ -720,32 +760,127 @@ add_header:
                 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI4 "
                        "returned %d\n", &conn->c_faddr, ret);
                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
-                if (prev->s_rm) {
-                        ic->i_rm = prev->s_rm;
-                        prev->s_rm = NULL;
+                rds_ib_sub_signaled(ic, nr_sig);
+                if (prev->s_op) {
+                        ic->i_data_op = prev->s_op;
+                        prev->s_op = NULL;
                 }
 
                 rds_ib_conn_error(ic->conn, "ib_post_send failed\n");
                 goto out;
         }
 
-        ret = sent;
+        ret = bytes_sent;
 out:
         BUG_ON(adv_credits);
         return ret;
 }
 
-int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op)
+/*
+ * Issue atomic operation.
+ * A simplified version of the rdma case, we always map 1 SG, and
+ * only 8 bytes, for the return value from the atomic operation.
+ */
+int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op)
+{
+        struct rds_ib_connection *ic = conn->c_transport_data;
+        struct rds_ib_send_work *send = NULL;
+        struct ib_send_wr *failed_wr;
+        struct rds_ib_device *rds_ibdev;
+        u32 pos;
+        u32 work_alloc;
+        int ret;
+        int nr_sig = 0;
+
+        rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
+
+        work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos);
+        if (work_alloc != 1) {
+                rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
+                rds_ib_stats_inc(s_ib_tx_ring_full);
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        /* address of send request in ring */
+        send = &ic->i_sends[pos];
+        send->s_queued = jiffies;
+
+        if (op->op_type == RDS_ATOMIC_TYPE_CSWP) {
+                send->s_wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP;
+                send->s_wr.wr.atomic.compare_add = op->op_m_cswp.compare;
+                send->s_wr.wr.atomic.swap = op->op_m_cswp.swap;
+                send->s_wr.wr.atomic.compare_add_mask = op->op_m_cswp.compare_mask;
+                send->s_wr.wr.atomic.swap_mask = op->op_m_cswp.swap_mask;
+        } else { /* FADD */
+                send->s_wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD;
+                send->s_wr.wr.atomic.compare_add = op->op_m_fadd.add;
+                send->s_wr.wr.atomic.swap = 0;
+                send->s_wr.wr.atomic.compare_add_mask = op->op_m_fadd.nocarry_mask;
+                send->s_wr.wr.atomic.swap_mask = 0;
+        }
+        nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify);
+        send->s_wr.num_sge = 1;
+        send->s_wr.next = NULL;
+        send->s_wr.wr.atomic.remote_addr = op->op_remote_addr;
+        send->s_wr.wr.atomic.rkey = op->op_rkey;
+        send->s_op = op;
+        rds_message_addref(container_of(send->s_op, struct rds_message, atomic));
+
+        /* map 8 byte retval buffer to the device */
+        ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE);
+        rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret);
+        if (ret != 1) {
+                rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
+                rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
+                ret = -ENOMEM; /* XXX ? */
+                goto out;
+        }
+
+        /* Convert our struct scatterlist to struct ib_sge */
+        send->s_sge[0].addr = ib_sg_dma_address(ic->i_cm_id->device, op->op_sg);
+        send->s_sge[0].length = ib_sg_dma_len(ic->i_cm_id->device, op->op_sg);
+        send->s_sge[0].lkey = ic->i_mr->lkey;
+
+        rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr,
+                 send->s_sge[0].addr, send->s_sge[0].length);
+
+        if (nr_sig)
+                atomic_add(nr_sig, &ic->i_signaled_sends);
+
+        failed_wr = &send->s_wr;
+        ret = ib_post_send(ic->i_cm_id->qp, &send->s_wr, &failed_wr);
+        rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic,
+                 send, &send->s_wr, ret, failed_wr);
+        BUG_ON(failed_wr != &send->s_wr);
+        if (ret) {
+                printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI4 "
+                       "returned %d\n", &conn->c_faddr, ret);
+                rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
+                rds_ib_sub_signaled(ic, nr_sig);
+                goto out;
+        }
+
+        if (unlikely(failed_wr != &send->s_wr)) {
+                printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
+                BUG_ON(failed_wr != &send->s_wr);
+        }
+
+out:
+        return ret;
+}
+
+int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op)
 {
         struct rds_ib_connection *ic = conn->c_transport_data;
         struct rds_ib_send_work *send = NULL;
         struct rds_ib_send_work *first;
         struct rds_ib_send_work *prev;
         struct ib_send_wr *failed_wr;
-        struct rds_ib_device *rds_ibdev;
         struct scatterlist *scat;
         unsigned long len;
-        u64 remote_addr = op->r_remote_addr;
+        u64 remote_addr = op->op_remote_addr;
+        u32 max_sge = ic->rds_ibdev->max_sge;
         u32 pos;
         u32 work_alloc;
         u32 i;
@@ -753,29 +888,28 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op)
         int sent;
         int ret;
         int num_sge;
-
-        rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
-
-        /* map the message the first time we see it */
-        if (!op->r_mapped) {
-                op->r_count = ib_dma_map_sg(ic->i_cm_id->device,
-                                        op->r_sg, op->r_nents, (op->r_write) ?
-                                        DMA_TO_DEVICE : DMA_FROM_DEVICE);
-                rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->r_count);
-                if (op->r_count == 0) {
+        int nr_sig = 0;
+
+        /* map the op the first time we see it */
+        if (!op->op_mapped) {
+                op->op_count = ib_dma_map_sg(ic->i_cm_id->device,
+                                             op->op_sg, op->op_nents, (op->op_write) ?
+                                             DMA_TO_DEVICE : DMA_FROM_DEVICE);
+                rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->op_count);
+                if (op->op_count == 0) {
                         rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
                         ret = -ENOMEM; /* XXX ? */
                         goto out;
                 }
 
-                op->r_mapped = 1;
+                op->op_mapped = 1;
         }
 
         /*
          * Instead of knowing how to return a partial rdma read/write we insist that there
          * be enough work requests to send the entire message.
          */
-        i = ceil(op->r_count, rds_ibdev->max_sge);
+        i = ceil(op->op_count, max_sge);
 
         work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
         if (work_alloc != i) {
@@ -788,30 +922,24 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op)
         send = &ic->i_sends[pos];
         first = send;
         prev = NULL;
-        scat = &op->r_sg[0];
+        scat = &op->op_sg[0];
         sent = 0;
-        num_sge = op->r_count;
+        num_sge = op->op_count;
 
-        for (i = 0; i < work_alloc && scat != &op->r_sg[op->r_count]; i++) {
+        for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) {
                 send->s_wr.send_flags = 0;
                 send->s_queued = jiffies;
-                /*
-                 * We want to delay signaling completions just enough to get
-                 * the batching benefits but not so much that we create dead time on the wire.
-                 */
-                if (ic->i_unsignaled_wrs-- == 0) {
-                        ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
-                        send->s_wr.send_flags = IB_SEND_SIGNALED;
-                }
+                send->s_op = NULL;
+
+                nr_sig += rds_ib_set_wr_signal_state(ic, send, op->op_notify);
 
-                send->s_wr.opcode = op->r_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
+                send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
                 send->s_wr.wr.rdma.remote_addr = remote_addr;
-                send->s_wr.wr.rdma.rkey = op->r_key;
-                send->s_op = op;
+                send->s_wr.wr.rdma.rkey = op->op_rkey;
 
-                if (num_sge > rds_ibdev->max_sge) {
-                        send->s_wr.num_sge = rds_ibdev->max_sge;
-                        num_sge -= rds_ibdev->max_sge;
+                if (num_sge > max_sge) {
+                        send->s_wr.num_sge = max_sge;
+                        num_sge -= max_sge;
                 } else {
                         send->s_wr.num_sge = num_sge;
                 }
@@ -821,7 +949,7 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op)
                 if (prev)
                         prev->s_wr.next = &send->s_wr;
 
-                for (j = 0; j < send->s_wr.num_sge && scat != &op->r_sg[op->r_count]; j++) {
+                for (j = 0; j < send->s_wr.num_sge && scat != &op->op_sg[op->op_count]; j++) {
                         len = ib_sg_dma_len(ic->i_cm_id->device, scat);
                         send->s_sge[j].addr =
                                  ib_sg_dma_address(ic->i_cm_id->device, scat);
@@ -843,15 +971,20 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op)
                         send = ic->i_sends;
         }
 
-        /* if we finished the message then send completion owns it */
-        if (scat == &op->r_sg[op->r_count])
-                prev->s_wr.send_flags = IB_SEND_SIGNALED;
+        /* give a reference to the last op */
+        if (scat == &op->op_sg[op->op_count]) {
+                prev->s_op = op;
+                rds_message_addref(container_of(op, struct rds_message, rdma));
+        }
 
         if (i < work_alloc) {
                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
                 work_alloc = i;
         }
 
+        if (nr_sig)
+                atomic_add(nr_sig, &ic->i_signaled_sends);
+
         failed_wr = &first->s_wr;
         ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
         rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
@@ -861,6 +994,7 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op)
                 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI4 "
                        "returned %d\n", &conn->c_faddr, ret);
                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
+                rds_ib_sub_signaled(ic, nr_sig);
                 goto out;
         }