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-rw-r--r--net/sunrpc/xprtrdma/rpc_rdma.c21
-rw-r--r--net/sunrpc/xprtrdma/transport.c9
-rw-r--r--net/sunrpc/xprtrdma/xprt_rdma.h5
3 files changed, 33 insertions, 2 deletions
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 721dae795d6..d245c0bf787 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -118,6 +118,10 @@ rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos,
}
if (xdrbuf->tail[0].iov_len) {
+ /* the rpcrdma protocol allows us to omit any trailing
+ * xdr pad bytes, saving the server an RDMA operation. */
+ if (xdrbuf->tail[0].iov_len < 4 && xprt_rdma_pad_optimize)
+ return n;
if (n == nsegs)
return 0;
seg[n].mr_page = NULL;
@@ -594,7 +598,7 @@ rpcrdma_count_chunks(struct rpcrdma_rep *rep, unsigned int max, int wrchunk, __b
* Scatter inline received data back into provided iov's.
*/
static void
-rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len)
+rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
{
int i, npages, curlen, olen;
char *destp;
@@ -660,6 +664,13 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len)
} else
rqst->rq_rcv_buf.tail[0].iov_len = 0;
+ if (pad) {
+ /* implicit padding on terminal chunk */
+ unsigned char *p = rqst->rq_rcv_buf.tail[0].iov_base;
+ while (pad--)
+ p[rqst->rq_rcv_buf.tail[0].iov_len++] = 0;
+ }
+
if (copy_len)
dprintk("RPC: %s: %d bytes in"
" %d extra segments (%d lost)\n",
@@ -794,14 +805,20 @@ repost:
((unsigned char *)iptr - (unsigned char *)headerp);
status = rep->rr_len + rdmalen;
r_xprt->rx_stats.total_rdma_reply += rdmalen;
+ /* special case - last chunk may omit padding */
+ if (rdmalen &= 3) {
+ rdmalen = 4 - rdmalen;
+ status += rdmalen;
+ }
} else {
/* else ordinary inline */
+ rdmalen = 0;
iptr = (__be32 *)((unsigned char *)headerp + 28);
rep->rr_len -= 28; /*sizeof *headerp;*/
status = rep->rr_len;
}
/* Fix up the rpc results for upper layer */
- rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len);
+ rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len, rdmalen);
break;
case __constant_htonl(RDMA_NOMSG):
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index ec6d1e7a194..c7d2380bb5e 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -71,6 +71,7 @@ static unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE;
static unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE;
static unsigned int xprt_rdma_inline_write_padding;
static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_FRMR;
+ int xprt_rdma_pad_optimize = 0;
#ifdef RPC_DEBUG
@@ -136,6 +137,14 @@ static ctl_table xr_tunables_table[] = {
.extra2 = &max_memreg,
},
{
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "rdma_pad_optimize",
+ .data = &xprt_rdma_pad_optimize,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
.ctl_name = 0,
},
};
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 2db2344d487..fde6499a53b 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -280,6 +280,11 @@ struct rpcrdma_xprt {
#define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, xprt)
#define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
+/* Setting this to 0 ensures interoperability with early servers.
+ * Setting this to 1 enhances certain unaligned read/write performance.
+ * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
+extern int xprt_rdma_pad_optimize;
+
/*
* Interface Adapter calls - xprtrdma/verbs.c
*/