svcrdma: Add FRMR get/put services

Add services for the allocating, freeing, and unmapping Fast Reg MR. These
services will be used by the transport connection setup, send and receive
routines.

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

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 49e458d..3425268 100644 (file)
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -214,6 +214,9 @@ extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
 extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
 extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
 extern void svc_rdma_put_req_map(struct svc_rdma_req_map *);
+extern struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *);
+extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
+                             struct svc_rdma_fastreg_mr *);
 extern void svc_sq_reap(struct svcxprt_rdma *);
 extern void svc_rq_reap(struct svcxprt_rdma *);
 extern struct svc_xprt_class svc_rdma_class;

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 900cb69..f0b5c5f 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -100,6 +100,7 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
        ctxt->xprt = xprt;
        INIT_LIST_HEAD(&ctxt->dto_q);
        ctxt->count = 0;
+       ctxt->frmr = NULL;
        atomic_inc(&xprt->sc_ctxt_used);
        return ctxt;
 }
@@ -109,11 +110,19 @@ 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++) {
-               atomic_dec(&xprt->sc_dma_used);
-               ib_dma_unmap_single(xprt->sc_cm_id->device,
-                                   ctxt->sge[i].addr,
-                                   ctxt->sge[i].length,
-                                   ctxt->direction);
+               /*
+                * Unmap the DMA addr in the SGE if the lkey matches
+                * the sc_dma_lkey, otherwise, ignore it since it is
+                * an FRMR lkey and will be unmapped later when the
+                * last WR that uses it completes.
+                */
+               if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
+                       atomic_dec(&xprt->sc_dma_used);
+                       ib_dma_unmap_single(xprt->sc_cm_id->device,
+                                           ctxt->sge[i].addr,
+                                           ctxt->sge[i].length,
+                                           ctxt->direction);
+               }
        }
 }
 
@@ -150,6 +159,7 @@ struct svc_rdma_req_map *svc_rdma_get_req_map(void)
                schedule_timeout_uninterruptible(msecs_to_jiffies(500));
        }
        map->count = 0;
+       map->frmr = NULL;
        return map;
 }
 
@@ -425,10 +435,12 @@ static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
        INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
        INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
        INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
+       INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
        init_waitqueue_head(&cma_xprt->sc_send_wait);
 
        spin_lock_init(&cma_xprt->sc_lock);
        spin_lock_init(&cma_xprt->sc_rq_dto_lock);
+       spin_lock_init(&cma_xprt->sc_frmr_q_lock);
 
        cma_xprt->sc_ord = svcrdma_ord;
 
@@ -686,6 +698,97 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
        return ERR_PTR(ret);
 }
 
+static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
+{
+       struct ib_mr *mr;
+       struct ib_fast_reg_page_list *pl;
+       struct svc_rdma_fastreg_mr *frmr;
+
+       frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
+       if (!frmr)
+               goto err;
+
+       mr = ib_alloc_fast_reg_mr(xprt->sc_pd, RPCSVC_MAXPAGES);
+       if (!mr)
+               goto err_free_frmr;
+
+       pl = ib_alloc_fast_reg_page_list(xprt->sc_cm_id->device,
+                                        RPCSVC_MAXPAGES);
+       if (!pl)
+               goto err_free_mr;
+
+       frmr->mr = mr;
+       frmr->page_list = pl;
+       INIT_LIST_HEAD(&frmr->frmr_list);
+       return frmr;
+
+ err_free_mr:
+       ib_dereg_mr(mr);
+ err_free_frmr:
+       kfree(frmr);
+ err:
+       return ERR_PTR(-ENOMEM);
+}
+
+static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
+{
+       struct svc_rdma_fastreg_mr *frmr;
+
+       while (!list_empty(&xprt->sc_frmr_q)) {
+               frmr = list_entry(xprt->sc_frmr_q.next,
+                                 struct svc_rdma_fastreg_mr, frmr_list);
+               list_del_init(&frmr->frmr_list);
+               ib_dereg_mr(frmr->mr);
+               ib_free_fast_reg_page_list(frmr->page_list);
+               kfree(frmr);
+       }
+}
+
+struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
+{
+       struct svc_rdma_fastreg_mr *frmr = NULL;
+
+       spin_lock_bh(&rdma->sc_frmr_q_lock);
+       if (!list_empty(&rdma->sc_frmr_q)) {
+               frmr = list_entry(rdma->sc_frmr_q.next,
+                                 struct svc_rdma_fastreg_mr, frmr_list);
+               list_del_init(&frmr->frmr_list);
+               frmr->map_len = 0;
+               frmr->page_list_len = 0;
+       }
+       spin_unlock_bh(&rdma->sc_frmr_q_lock);
+       if (frmr)
+               return frmr;
+
+       return rdma_alloc_frmr(rdma);
+}
+
+static void frmr_unmap_dma(struct svcxprt_rdma *xprt,
+                          struct svc_rdma_fastreg_mr *frmr)
+{
+       int page_no;
+       for (page_no = 0; page_no < frmr->page_list_len; page_no++) {
+               dma_addr_t addr = frmr->page_list->page_list[page_no];
+               if (ib_dma_mapping_error(frmr->mr->device, addr))
+                       continue;
+               atomic_dec(&xprt->sc_dma_used);
+               ib_dma_unmap_single(frmr->mr->device, addr, PAGE_SIZE,
+                                   frmr->direction);
+       }
+}
+
+void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
+                      struct svc_rdma_fastreg_mr *frmr)
+{
+       if (frmr) {
+               frmr_unmap_dma(rdma, frmr);
+               spin_lock_bh(&rdma->sc_frmr_q_lock);
+               BUG_ON(!list_empty(&frmr->frmr_list));
+               list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
+               spin_unlock_bh(&rdma->sc_frmr_q_lock);
+       }
+}
+
 /*
  * This is the xpo_recvfrom function for listening endpoints. Its
  * purpose is to accept incoming connections. The CMA callback handler
@@ -961,6 +1064,9 @@ static void __svc_rdma_free(struct work_struct *work)
        WARN_ON(atomic_read(&rdma->sc_ctxt_used) != 0);
        WARN_ON(atomic_read(&rdma->sc_dma_used) != 0);
 
+       /* De-allocate fastreg mr */
+       rdma_dealloc_frmr_q(rdma);
+
        /* Destroy the QP if present (not a listener) */
        if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
                ib_destroy_qp(rdma->sc_qp);