svcrdma: Plant reader function in struct svcxprt_rdma

The RDMA reader function doesn't change once an svcxprt_rdma is
instantiated. Instead of checking sc_devcap during every incoming
RPC, set the reader function once when the connection is accepted.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 2280325..f161e30 100644 (file)
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -150,6 +150,10 @@ struct svcxprt_rdma {
        struct ib_cq         *sc_rq_cq;
        struct ib_cq         *sc_sq_cq;
        struct ib_mr         *sc_phys_mr;       /* MR for server memory */
+       int                  (*sc_reader)(struct svcxprt_rdma *,
+                                         struct svc_rqst *,
+                                         struct svc_rdma_op_ctxt *,
+                                         int *, u32 *, u32, u32, u64, bool);
        u32                  sc_dev_caps;       /* distilled device caps */
        u32                  sc_dma_lkey;       /* local dma key */
        unsigned int         sc_frmr_pg_list_len;
@@ -195,6 +199,12 @@ extern int svc_rdma_xdr_get_reply_hdr_len(struct rpcrdma_msg *);
 
 /* svc_rdma_recvfrom.c */
 extern int svc_rdma_recvfrom(struct svc_rqst *);
+extern int rdma_read_chunk_lcl(struct svcxprt_rdma *, struct svc_rqst *,
+                              struct svc_rdma_op_ctxt *, int *, u32 *,
+                              u32, u32, u64, bool);
+extern int rdma_read_chunk_frmr(struct svcxprt_rdma *, struct svc_rqst *,
+                               struct svc_rdma_op_ctxt *, int *, u32 *,
+                               u32, u32, u64, bool);
 
 /* svc_rdma_sendto.c */
 extern int svc_rdma_sendto(struct svc_rqst *);

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 577f865..c3aebc1 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -117,26 +117,16 @@ static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
                return min_t(int, sge_count, xprt->sc_max_sge);
 }
 
-typedef int (*rdma_reader_fn)(struct svcxprt_rdma *xprt,
-                             struct svc_rqst *rqstp,
-                             struct svc_rdma_op_ctxt *head,
-                             int *page_no,
-                             u32 *page_offset,
-                             u32 rs_handle,
-                             u32 rs_length,
-                             u64 rs_offset,
-                             int last);
-
 /* Issue an RDMA_READ using the local lkey to map the data sink */
-static int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
-                              struct svc_rqst *rqstp,
-                              struct svc_rdma_op_ctxt *head,
-                              int *page_no,
-                              u32 *page_offset,
-                              u32 rs_handle,
-                              u32 rs_length,
-                              u64 rs_offset,
-                              int last)
+int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
+                       struct svc_rqst *rqstp,
+                       struct svc_rdma_op_ctxt *head,
+                       int *page_no,
+                       u32 *page_offset,
+                       u32 rs_handle,
+                       u32 rs_length,
+                       u64 rs_offset,
+                       bool last)
 {
        struct ib_send_wr read_wr;
        int pages_needed = PAGE_ALIGN(*page_offset + rs_length) >> PAGE_SHIFT;
@@ -221,15 +211,15 @@ static int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
 }
 
 /* Issue an RDMA_READ using an FRMR to map the data sink */
-static int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
-                               struct svc_rqst *rqstp,
-                               struct svc_rdma_op_ctxt *head,
-                               int *page_no,
-                               u32 *page_offset,
-                               u32 rs_handle,
-                               u32 rs_length,
-                               u64 rs_offset,
-                               int last)
+int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
+                        struct svc_rqst *rqstp,
+                        struct svc_rdma_op_ctxt *head,
+                        int *page_no,
+                        u32 *page_offset,
+                        u32 rs_handle,
+                        u32 rs_length,
+                        u64 rs_offset,
+                        bool last)
 {
        struct ib_send_wr read_wr;
        struct ib_send_wr inv_wr;
@@ -374,9 +364,9 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
 {
        int page_no, ret;
        struct rpcrdma_read_chunk *ch;
-       u32 page_offset, byte_count;
+       u32 handle, page_offset, byte_count;
        u64 rs_offset;
-       rdma_reader_fn reader;
+       bool last;
 
        /* If no read list is present, return 0 */
        ch = svc_rdma_get_read_chunk(rmsgp);
@@ -399,27 +389,20 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
        head->arg.len = rqstp->rq_arg.len;
        head->arg.buflen = rqstp->rq_arg.buflen;
 
-       /* Use FRMR if supported */
-       if (xprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)
-               reader = rdma_read_chunk_frmr;
-       else
-               reader = rdma_read_chunk_lcl;
-
        page_no = 0; page_offset = 0;
        for (ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
             ch->rc_discrim != 0; ch++) {
-
+               handle = be32_to_cpu(ch->rc_target.rs_handle);
+               byte_count = be32_to_cpu(ch->rc_target.rs_length);
                xdr_decode_hyper((__be32 *)&ch->rc_target.rs_offset,
                                 &rs_offset);
-               byte_count = ntohl(ch->rc_target.rs_length);
 
                while (byte_count > 0) {
-                       ret = reader(xprt, rqstp, head,
-                                    &page_no, &page_offset,
-                                    ntohl(ch->rc_target.rs_handle),
-                                    byte_count, rs_offset,
-                                    ((ch+1)->rc_discrim == 0) /* last */
-                                    );
+                       last = (ch + 1)->rc_discrim == xdr_zero;
+                       ret = xprt->sc_reader(xprt, rqstp, head,
+                                             &page_no, &page_offset,
+                                             handle, byte_count,
+                                             rs_offset, last);
                        if (ret < 0)
                                goto err;
                        byte_count -= ret;

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index f2e059b..f609c1c 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -974,10 +974,12 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
         * NB:  iWARP requires remote write access for the data sink
         *      of an RDMA_READ. IB does not.
         */
+       newxprt->sc_reader = rdma_read_chunk_lcl;
        if (devattr.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
                newxprt->sc_frmr_pg_list_len =
                        devattr.max_fast_reg_page_list_len;
                newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
+               newxprt->sc_reader = rdma_read_chunk_frmr;
        }
 
        /*