On 2/21/2020 2:00 PM, Chuck Lever wrote:
Make a Protection Domain (PD) a per-connection resource rather than
a per-transport resource. In other words, when the connection
terminates, the PD is destroyed.
Thus there is one less HW resource that remains allocated to a
transport after a connection is closed.
That's a good goal, but there are cases where the upper layer may
want the PD to be shared. For example, in a multichannel configuration,
where RDMA may not be constrained to use a single connection.
How would this approach support such a requirement? Can a PD be
provided to a new connection?
Tom.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/verbs.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index f361213a8157..36fe7baea014 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -363,14 +363,6 @@ static void rpcrdma_update_cm_private(struct rpcrdma_xprt *r_xprt,
rc = PTR_ERR(ia->ri_id);
goto out_err;
}
-
- ia->ri_pd = ib_alloc_pd(ia->ri_id->device, 0);
- if (IS_ERR(ia->ri_pd)) {
- rc = PTR_ERR(ia->ri_pd);
- pr_err("rpcrdma: ib_alloc_pd() returned %d\n", rc);
- goto out_err;
- }
-
return 0;
out_err:
@@ -403,9 +395,6 @@ static void rpcrdma_update_cm_private(struct rpcrdma_xprt *r_xprt,
rpcrdma_ep_destroy(r_xprt);
- ib_dealloc_pd(ia->ri_pd);
- ia->ri_pd = NULL;
-
/* Allow waiters to continue */
complete(&ia->ri_remove_done);
@@ -423,11 +412,6 @@ static void rpcrdma_update_cm_private(struct rpcrdma_xprt *r_xprt,
if (ia->ri_id && !IS_ERR(ia->ri_id))
rdma_destroy_id(ia->ri_id);
ia->ri_id = NULL;
-
- /* If the pd is still busy, xprtrdma missed freeing a resource */
- if (ia->ri_pd && !IS_ERR(ia->ri_pd))
- ib_dealloc_pd(ia->ri_pd);
- ia->ri_pd = NULL;
}
static int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt,
@@ -514,6 +498,12 @@ static int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt,
ep->rep_remote_cma.flow_control = 0;
ep->rep_remote_cma.rnr_retry_count = 0;
+ ia->ri_pd = ib_alloc_pd(id->device, 0);
+ if (IS_ERR(ia->ri_pd)) {
+ rc = PTR_ERR(ia->ri_pd);
+ goto out_destroy;
+ }
+
rc = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);
if (rc)
goto out_destroy;
@@ -540,6 +530,10 @@ static void rpcrdma_ep_destroy(struct rpcrdma_xprt *r_xprt)
if (ep->rep_attr.send_cq)
ib_free_cq(ep->rep_attr.send_cq);
ep->rep_attr.send_cq = NULL;
+
+ if (ia->ri_pd)
+ ib_dealloc_pd(ia->ri_pd);
+ ia->ri_pd = NULL;
}
/* Re-establish a connection after a device removal event.
