RDS: Implement atomic operations
Implement a CMSG-based interface to do FADD and CSWP ops.
Alter send routines to handle atomic ops.
Add atomic counters to stats.
Add xmit_atomic() to struct rds_transport
Inline rds_ib_send_unmap_rdma into unmap_rm
Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
index f0edfdb..b2bd164 100644
--- a/net/rds/ib_send.c
+++ b/net/rds/ib_send.c
@@ -62,15 +62,17 @@
rds_rdma_send_complete(rm, notify_status);
}
-static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic,
- struct rds_rdma_op *op)
+static void rds_ib_send_atomic_complete(struct rds_message *rm,
+ int wc_status)
{
- if (op->r_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;
- }
+ int notify_status;
+
+ if (wc_status != IB_WC_SUCCESS)
+ notify_status = RDS_RDMA_OTHER_ERROR;
+ else
+ notify_status = RDS_RDMA_SUCCESS;
+
+ rds_atomic_send_complete(rm, notify_status);
}
static void rds_ib_send_unmap_rm(struct rds_ib_connection *ic,
@@ -86,7 +88,14 @@
DMA_TO_DEVICE);
if (rm->rdma.m_rdma_op.r_active) {
- rds_ib_send_unmap_rdma(ic, &rm->rdma.m_rdma_op);
+ struct rds_rdma_op *op = &rm->rdma.m_rdma_op;
+
+ if (op->r_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;
+ }
/* If the user asked for a completion notification on this
* message, we can implement three different semantics:
@@ -116,6 +125,24 @@
rds_stats_add(s_recv_rdma_bytes, rm->rdma.m_rdma_op.r_bytes);
}
+ if (rm->atomic.op_active) {
+ struct rm_atomic_op *op = &rm->atomic;
+
+ /* 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;
+ }
+
+ rds_ib_send_atomic_complete(rm, wc_status);
+
+ if (rm->atomic.op_type == RDS_ATOMIC_TYPE_CSWP)
+ rds_stats_inc(s_atomic_cswp);
+ else
+ rds_stats_inc(s_atomic_fadd);
+ }
+
/* If anyone waited for this message to get flushed out, wake
* them up now */
rds_message_unmapped(rm);
@@ -158,12 +185,9 @@
u32 i;
for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
- if (send->s_wr.opcode == 0xdead)
+ if (!send->s_rm || 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);
+ rds_ib_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR);
}
}
@@ -218,6 +242,8 @@
break;
case IB_WR_RDMA_WRITE:
case IB_WR_RDMA_READ:
+ case IB_WR_ATOMIC_FETCH_AND_ADD:
+ case IB_WR_ATOMIC_CMP_AND_SWP:
/* Nothing to be done - the SG list will be unmapped
* when the SEND completes. */
break;
@@ -243,8 +269,7 @@
rm = rds_send_get_message(conn, send->s_op);
if (rm) {
- if (rm->rdma.m_rdma_op.r_active)
- rds_ib_send_unmap_rdma(ic, &rm->rdma.m_rdma_op);
+ rds_ib_send_unmap_rm(ic, send, wc.status);
rds_ib_send_rdma_complete(rm, wc.status);
rds_message_put(rm);
}
@@ -736,6 +761,89 @@
return ret;
}
+/*
+ * 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;
+
+ 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_ATOMIC_CMP_AND_SWP;
+ send->s_wr.wr.atomic.compare_add = op->op_compare;
+ send->s_wr.wr.atomic.swap = op->op_swap_add;
+ } else { /* FADD */
+ send->s_wr.opcode = IB_WR_ATOMIC_FETCH_AND_ADD;
+ send->s_wr.wr.atomic.compare_add = op->op_swap_add;
+ send->s_wr.wr.atomic.swap = 0;
+ }
+ send->s_wr.send_flags = IB_SEND_SIGNALED;
+ 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;
+
+ /* 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);
+
+ 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);
+ 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 rds_rdma_op *op)
{
struct rds_ib_connection *ic = conn->c_transport_data;