Extra resources for handling backchannel requests have to be
pre-allocated when a transport instance is created. Set up
additional fields in svcxprt_rdma to track these resources.
The max_requests fields are elements of the RPC-over-RDMA
protocol, so they should be u32. To ensure that unsigned
arithmetic is used everywhere, some other fields in the
svcxprt_rdma struct are updated.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc_rdma.h | 13 ++++++++++---
net/sunrpc/xprtrdma/svc_rdma.c | 6 ++++--
net/sunrpc/xprtrdma/svc_rdma_transport.c | 24 ++++++++++++++----------
3 files changed, 28 insertions(+), 15 deletions(-)
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index aeffa30..9a2c418 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -51,6 +51,7 @@
/* RPC/RDMA parameters and stats */
extern unsigned int svcrdma_ord;
extern unsigned int svcrdma_max_requests;
+extern unsigned int svcrdma_max_bc_requests;
extern unsigned int svcrdma_max_req_size;
extern atomic_t rdma_stat_recv;
@@ -134,10 +135,11 @@ struct svcxprt_rdma {
int sc_max_sge;
int sc_max_sge_rd; /* max sge for read target */
- int sc_sq_depth; /* Depth of SQ */
atomic_t sc_sq_count; /* Number of SQ WR on queue */
-
- int sc_max_requests; /* Depth of RQ */
+ unsigned int sc_sq_depth; /* Depth of SQ */
+ unsigned int sc_rq_depth; /* Depth of RQ */
+ u32 sc_max_requests; /* Forward credits */
+ u32 sc_max_bc_requests;/* Backward credits */
int sc_max_req_size; /* Size of each RQ WR buf */
struct ib_pd *sc_pd;
@@ -186,6 +188,11 @@ struct svcxprt_rdma {
#define RPCRDMA_MAX_REQUESTS 32
#define RPCRDMA_MAX_REQ_SIZE 4096
+/* Typical ULP usage of BC requests is NFSv4.1 backchannel. Our
+ * current NFSv4.1 implementation supports one backchannel slot.
+ */
+#define RPCRDMA_MAX_BC_REQUESTS 2
+
#define RPCSVC_MAXPAYLOAD_RDMA RPCSVC_MAXPAYLOAD
/* svc_rdma_marshal.c */
diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index e894e06..c846ca9 100644
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -55,6 +55,7 @@ unsigned int svcrdma_ord = RPCRDMA_ORD;
static unsigned int min_ord = 1;
static unsigned int max_ord = 4096;
unsigned int svcrdma_max_requests = RPCRDMA_MAX_REQUESTS;
+unsigned int svcrdma_max_bc_requests = RPCRDMA_MAX_BC_REQUESTS;
static unsigned int min_max_requests = 4;
static unsigned int max_max_requests = 16384;
unsigned int svcrdma_max_req_size = RPCRDMA_MAX_REQ_SIZE;
@@ -245,9 +246,10 @@ int svc_rdma_init(void)
{
dprintk("SVCRDMA Module Init, register RPC RDMA transport\n");
dprintk("\tsvcrdma_ord : %d\n", svcrdma_ord);
- dprintk("\tmax_requests : %d\n", svcrdma_max_requests);
- dprintk("\tsq_depth : %d\n",
+ dprintk("\tmax_requests : %u\n", svcrdma_max_requests);
+ dprintk("\tsq_depth : %u\n",
svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT);
+ dprintk("\tmax_bc_requests : %u\n", svcrdma_max_bc_requests);
dprintk("\tmax_inline : %d\n", svcrdma_max_req_size);
svc_rdma_wq = alloc_workqueue("svc_rdma", 0, 0);
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 694ade4..35326a3 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -169,12 +169,12 @@ static struct svc_rdma_op_ctxt *alloc_ctxt(struct svcxprt_rdma *xprt,
static bool svc_rdma_prealloc_ctxts(struct svcxprt_rdma *xprt)
{
- int i;
+ unsigned int i;
/* Each RPC/RDMA credit can consume a number of send
* and receive WQEs. One ctxt is allocated for each.
*/
- i = xprt->sc_sq_depth + xprt->sc_max_requests;
+ i = xprt->sc_sq_depth + xprt->sc_rq_depth;
while (i--) {
struct svc_rdma_op_ctxt *ctxt;
@@ -285,7 +285,7 @@ static struct svc_rdma_req_map *alloc_req_map(gfp_t flags)
static bool svc_rdma_prealloc_maps(struct svcxprt_rdma *xprt)
{
- int i;
+ unsigned int i;
/* One for each receive buffer on this connection. */
i = xprt->sc_max_requests;
@@ -1016,8 +1016,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
struct ib_device *dev;
int uninitialized_var(dma_mr_acc);
int need_dma_mr = 0;
+ unsigned int i;
int ret = 0;
- int i;
listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
clear_bit(XPT_CONN, &xprt->xpt_flags);
@@ -1046,9 +1046,13 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
newxprt->sc_max_sge_rd = min_t(size_t, dev->max_sge_rd,
RPCSVC_MAXPAGES);
newxprt->sc_max_req_size = svcrdma_max_req_size;
- newxprt->sc_max_requests = min((size_t)dev->max_qp_wr,
- (size_t)svcrdma_max_requests);
- newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;
+ newxprt->sc_max_requests = min_t(u32, dev->max_qp_wr,
+ svcrdma_max_requests);
+ newxprt->sc_max_bc_requests = min_t(u32, dev->max_qp_wr,
+ svcrdma_max_bc_requests);
+ newxprt->sc_rq_depth = newxprt->sc_max_requests +
+ newxprt->sc_max_bc_requests;
+ newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_rq_depth;
if (!svc_rdma_prealloc_ctxts(newxprt))
goto errout;
@@ -1077,7 +1081,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
dprintk("svcrdma: error creating SQ CQ for connect request\n");
goto errout;
}
- cq_attr.cqe = newxprt->sc_max_requests;
+ cq_attr.cqe = newxprt->sc_rq_depth;
newxprt->sc_rq_cq = ib_create_cq(dev,
rq_comp_handler,
cq_event_handler,
@@ -1092,7 +1096,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
qp_attr.event_handler = qp_event_handler;
qp_attr.qp_context = &newxprt->sc_xprt;
qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
- qp_attr.cap.max_recv_wr = newxprt->sc_max_requests;
+ qp_attr.cap.max_recv_wr = newxprt->sc_rq_depth;
qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
@@ -1183,7 +1187,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
newxprt->sc_dma_lkey = dev->local_dma_lkey;
/* Post receive buffers */
- for (i = 0; i < newxprt->sc_max_requests; i++) {
+ for (i = 0; i < newxprt->sc_rq_depth; i++) {
ret = svc_rdma_post_recv(newxprt, GFP_KERNEL);
if (ret) {
dprintk("svcrdma: failure posting receive buffers\n");
--
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