[PATCH v2 06/10] svcrdma: Plant reader function in struct svcxprt_rdma

Chuck Lever
2015-01-13T16:03:20Z

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-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---

include/linux/sunrpc/svc_rdma.h | 10 ++++
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 71 +++++++++++-------------------
net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 +
3 files changed, 39 insertions(+), 44 deletions(-)

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 2280325..f161e30 100644
--- 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
--- 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
--- 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;
}

/*