svcrdma: Use reply and chunk map for RDMA_READ processing

Modify the RDMA_READ processing to use the reply and chunk list mapping data
types. Also add a special purpose 'hdr_count' field in in the context to hold
the header page count instead of overloading the SGE length field and
corrupting the DMA map length.

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

1 files changed, 38 insertions, 45 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 06ab4841537b..d25971b42a74 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -112,11 +112,6 @@ static void rdma_build_arg_xdr(struct svc_rqst *rqstp,
         rqstp->rq_arg.tail[0].iov_len = 0;
 }
 
-struct chunk_sge {
-        int start;              /* sge no for this chunk */
-        int count;              /* sge count for this chunk */
-};
-
 /* Encode a read-chunk-list as an array of IB SGE
  *
  * Assumptions:
@@ -134,8 +129,8 @@ static int rdma_rcl_to_sge(struct svcxprt_rdma *xprt,
                            struct svc_rqst *rqstp,
                            struct svc_rdma_op_ctxt *head,
                            struct rpcrdma_msg *rmsgp,
-                           struct ib_sge *sge,
-                           struct chunk_sge *ch_sge_ary,
+                           struct svc_rdma_req_map *rpl_map,
+                           struct svc_rdma_req_map *chl_map,
                            int ch_count,
                            int byte_count)
 {
@@ -156,22 +151,18 @@ static int rdma_rcl_to_sge(struct svcxprt_rdma *xprt,
         head->arg.head[0] = rqstp->rq_arg.head[0];
         head->arg.tail[0] = rqstp->rq_arg.tail[0];
         head->arg.pages = &head->pages[head->count];
-        head->sge[0].length = head->count; /* save count of hdr pages */
+        head->hdr_count = head->count; /* save count of hdr pages */
         head->arg.page_base = 0;
         head->arg.page_len = ch_bytes;
         head->arg.len = rqstp->rq_arg.len + ch_bytes;
         head->arg.buflen = rqstp->rq_arg.buflen + ch_bytes;
         head->count++;
-        ch_sge_ary[0].start = 0;
+        chl_map->ch[0].start = 0;
         while (byte_count) {
+                rpl_map->sge[sge_no].iov_base =
+                        page_address(rqstp->rq_arg.pages[page_no]) + page_off;
                 sge_bytes = min_t(int, PAGE_SIZE-page_off, ch_bytes);
-                sge[sge_no].addr =
-                        ib_dma_map_page(xprt->sc_cm_id->device,
-                                        rqstp->rq_arg.pages[page_no],
-                                        page_off, sge_bytes,
-                                        DMA_FROM_DEVICE);
-                sge[sge_no].length = sge_bytes;
-                sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
+                rpl_map->sge[sge_no].iov_len = sge_bytes;
                 /*
                  * Don't bump head->count here because the same page
                  * may be used by multiple SGE.
@@ -187,11 +178,11 @@ static int rdma_rcl_to_sge(struct svcxprt_rdma *xprt,
                  * SGE, move to the next SGE
                  */
                 if (ch_bytes == 0) {
-                        ch_sge_ary[ch_no].count =
-                                sge_no - ch_sge_ary[ch_no].start;
+                        chl_map->ch[ch_no].count =
+                                sge_no - chl_map->ch[ch_no].start;
                         ch_no++;
                         ch++;
-                        ch_sge_ary[ch_no].start = sge_no;
+                        chl_map->ch[ch_no].start = sge_no;
                         ch_bytes = ch->rc_target.rs_length;
                         /* If bytes remaining account for next chunk */
                         if (byte_count) {
@@ -220,18 +211,24 @@ static int rdma_rcl_to_sge(struct svcxprt_rdma *xprt,
         return sge_no;
 }
 
-static void rdma_set_ctxt_sge(struct svc_rdma_op_ctxt *ctxt,
-                              struct ib_sge *sge,
+static void rdma_set_ctxt_sge(struct svcxprt_rdma *xprt,
+                              struct svc_rdma_op_ctxt *ctxt,
+                              struct kvec *vec,
                               u64 *sgl_offset,
                               int count)
 {
         int i;
 
         ctxt->count = count;
+        ctxt->direction = DMA_FROM_DEVICE;
         for (i = 0; i < count; i++) {
-                ctxt->sge[i].addr = sge[i].addr;
-                ctxt->sge[i].length = sge[i].length;
-                *sgl_offset = *sgl_offset + sge[i].length;
+                ctxt->sge[i].addr =
+                        ib_dma_map_single(xprt->sc_cm_id->device,
+                                          vec[i].iov_base, vec[i].iov_len,
+                                          DMA_FROM_DEVICE);
+                ctxt->sge[i].length = vec[i].iov_len;
+                ctxt->sge[i].lkey = xprt->sc_phys_mr->lkey;
+                *sgl_offset = *sgl_offset + vec[i].iov_len;
         }
 }
 
@@ -282,34 +279,29 @@ static int rdma_read_xdr(struct svcxprt_rdma *xprt,
         struct ib_send_wr read_wr;
         int err = 0;
         int ch_no;
-        struct ib_sge *sge;
         int ch_count;
         int byte_count;
         int sge_count;
         u64 sgl_offset;
         struct rpcrdma_read_chunk *ch;
         struct svc_rdma_op_ctxt *ctxt = NULL;
-        struct svc_rdma_op_ctxt *tmp_sge_ctxt;
-        struct svc_rdma_op_ctxt *tmp_ch_ctxt;
-        struct chunk_sge *ch_sge_ary;
+        struct svc_rdma_req_map *rpl_map;
+        struct svc_rdma_req_map *chl_map;
 
         /* If no read list is present, return 0 */
         ch = svc_rdma_get_read_chunk(rmsgp);
         if (!ch)
                 return 0;
 
-        /* Allocate temporary contexts to keep SGE */
-        BUG_ON(sizeof(struct ib_sge) < sizeof(struct chunk_sge));
-        tmp_sge_ctxt = svc_rdma_get_context(xprt);
-        sge = tmp_sge_ctxt->sge;
-        tmp_ch_ctxt = svc_rdma_get_context(xprt);
-        ch_sge_ary = (struct chunk_sge *)tmp_ch_ctxt->sge;
+        /* Allocate temporary reply and chunk maps */
+        rpl_map = svc_rdma_get_req_map();
+        chl_map = svc_rdma_get_req_map();
 
         svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
         if (ch_count > RPCSVC_MAXPAGES)
                 return -EINVAL;
         sge_count = rdma_rcl_to_sge(xprt, rqstp, hdr_ctxt, rmsgp,
-                                    sge, ch_sge_ary,
+                                    rpl_map, chl_map,
                                     ch_count, byte_count);
         sgl_offset = 0;
         ch_no = 0;
@@ -331,14 +323,15 @@ next_sge:
                 read_wr.wr.rdma.remote_addr =
                         get_unaligned(&(ch->rc_target.rs_offset)) +
                         sgl_offset;
-                read_wr.sg_list = &sge[ch_sge_ary[ch_no].start];
+                read_wr.sg_list = ctxt->sge;
                 read_wr.num_sge =
-                        rdma_read_max_sge(xprt, ch_sge_ary[ch_no].count);
-                rdma_set_ctxt_sge(ctxt, &sge[ch_sge_ary[ch_no].start],
+                        rdma_read_max_sge(xprt, chl_map->ch[ch_no].count);
+                rdma_set_ctxt_sge(xprt, ctxt,
+                                  &rpl_map->sge[chl_map->ch[ch_no].start],
                                   &sgl_offset,
                                   read_wr.num_sge);
                 if (((ch+1)->rc_discrim == 0) &&
-                    (read_wr.num_sge == ch_sge_ary[ch_no].count)) {
+                    (read_wr.num_sge == chl_map->ch[ch_no].count)) {
                         /*
                          * Mark the last RDMA_READ with a bit to
                          * indicate all RPC data has been fetched from
@@ -358,9 +351,9 @@ next_sge:
                 }
                 atomic_inc(&rdma_stat_read);
 
-                if (read_wr.num_sge < ch_sge_ary[ch_no].count) {
-                        ch_sge_ary[ch_no].count -= read_wr.num_sge;
-                        ch_sge_ary[ch_no].start += read_wr.num_sge;
+                if (read_wr.num_sge < chl_map->ch[ch_no].count) {
+                        chl_map->ch[ch_no].count -= read_wr.num_sge;
+                        chl_map->ch[ch_no].start += read_wr.num_sge;
                         goto next_sge;
                 }
                 sgl_offset = 0;
@@ -368,8 +361,8 @@ next_sge:
         }
 
  out:
-        svc_rdma_put_context(tmp_sge_ctxt, 0);
-        svc_rdma_put_context(tmp_ch_ctxt, 0);
+        svc_rdma_put_req_map(rpl_map);
+        svc_rdma_put_req_map(chl_map);
 
         /* Detach arg pages. svc_recv will replenish them */
         for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
@@ -399,7 +392,7 @@ static int rdma_read_complete(struct svc_rqst *rqstp,
                 rqstp->rq_pages[page_no] = head->pages[page_no];
         }
         /* Point rq_arg.pages past header */
-        rqstp->rq_arg.pages = &rqstp->rq_pages[head->sge[0].length];
+        rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count];
         rqstp->rq_arg.page_len = head->arg.page_len;
         rqstp->rq_arg.page_base = head->arg.page_base;