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>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index fc86338..7e8ee66 100644 (file)
--- 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);