svcrdma: Move the DMA unmap logic to the CQ handler

Separate DMA unmap from context destruction and perform DMA unmapping
in the SQ/RQ CQ reap functions. This is necessary to support software
based RDMA implementations that actually copy the data in their
ib_dma_unmap callback functions and architectures that don't have
cache coherent I/O busses.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

1 files changed, 14 insertions, 6 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index fc86338bcbb2..7e8ee66458ea 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -150,6 +150,18 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
         return ctxt;
 }
 
+static void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
+{
+        struct svcxprt_rdma *xprt = ctxt->xprt;
+        int i;
+        for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
+                ib_dma_unmap_single(xprt->sc_cm_id->device,
+                                    ctxt->sge[i].addr,
+                                    ctxt->sge[i].length,
+                                    ctxt->direction);
+        }
+}
+
 void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
 {
         struct svcxprt_rdma *xprt;
@@ -161,12 +173,6 @@ void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
                 for (i = 0; i < ctxt->count; i++)
                         put_page(ctxt->pages[i]);
 
-        for (i = 0; i < ctxt->count; i++)
-                ib_dma_unmap_single(xprt->sc_cm_id->device,
-                                    ctxt->sge[i].addr,
-                                    ctxt->sge[i].length,
-                                    ctxt->direction);
-
         spin_lock_bh(&xprt->sc_ctxt_lock);
         list_add(&ctxt->free_list, &xprt->sc_ctxt_free);
         spin_unlock_bh(&xprt->sc_ctxt_lock);
@@ -328,6 +334,7 @@ static void rq_cq_reap(struct svcxprt_rdma *xprt)
                 ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
                 ctxt->wc_status = wc.status;
                 ctxt->byte_len = wc.byte_len;
+                svc_rdma_unmap_dma(ctxt);
                 if (wc.status != IB_WC_SUCCESS) {
                         /* Close the transport */
                         dprintk("svcrdma: transport closing putting ctxt %p\n", ctxt);
@@ -377,6 +384,7 @@ static void sq_cq_reap(struct svcxprt_rdma *xprt)
                 ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
                 xprt = ctxt->xprt;
 
+                svc_rdma_unmap_dma(ctxt);
                 if (wc.status != IB_WC_SUCCESS)
                         /* Close the transport */
                         set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);