Merge tag 'nfsd-4.20' of git://linux-nfs.org/~bfields/linux

Pull nfsd updates from Bruce Fields:
 "Olga added support for the NFSv4.2 asynchronous copy protocol. We
  already supported COPY, by copying a limited amount of data and then
  returning a short result, letting the client resend. The asynchronous
  protocol should offer better performance at the expense of some
  complexity.

  The other highlight is Trond's work to convert the duplicate reply
  cache to a red-black tree, and to move it and some other server caches
  to RCU. (Previously these have meant taking global spinlocks on every
  RPC)

  Otherwise, some RDMA work and miscellaneous bugfixes"

* tag 'nfsd-4.20' of git://linux-nfs.org/~bfields/linux: (30 commits)
  lockd: fix access beyond unterminated strings in prints
  nfsd: Fix an Oops in free_session()
  nfsd: correctly decrement odstate refcount in error path
  svcrdma: Increase the default connection credit limit
  svcrdma: Remove try_module_get from backchannel
  svcrdma: Remove ->release_rqst call in bc reply handler
  svcrdma: Reduce max_send_sges
  nfsd: fix fall-through annotations
  knfsd: Improve lookup performance in the duplicate reply cache using an rbtree
  knfsd: Further simplify the cache lookup
  knfsd: Simplify NFS duplicate replay cache
  knfsd: Remove dead code from nfsd_cache_lookup
  SUNRPC: Simplify TCP receive code
  SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock
  SUNRPC: Remove non-RCU protected lookup
  NFS: Fix up a typo in nfs_dns_ent_put
  NFS: Lockless DNS lookups
  knfsd: Lockless lookup of NFSv4 identities.
  SUNRPC: Lockless server RPCSEC_GSS context lookup
  knfsd: Allow lockless lookups of the exports
  ...

2 files changed, 10 insertions, 23 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
index d3a1a237cee6..f3c147d70286 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
@@ -5,8 +5,6 @@
  * Support for backward direction RPCs on RPC/RDMA (server-side).
  */
 
-#include <linux/module.h>
-
 #include <linux/sunrpc/svc_rdma.h>
 
 #include "xprt_rdma.h"
@@ -32,7 +30,6 @@ int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, __be32 *rdma_resp,
 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 	struct kvec *dst, *src = &rcvbuf->head[0];
 	struct rpc_rqst *req;
-	unsigned long cwnd;
 	u32 credits;
 	size_t len;
 	__be32 xid;
@@ -66,6 +63,8 @@ int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, __be32 *rdma_resp,
 	if (dst->iov_len < len)
 		goto out_unlock;
 	memcpy(dst->iov_base, p, len);
+	xprt_pin_rqst(req);
+	spin_unlock(&xprt->queue_lock);
 
 	credits = be32_to_cpup(rdma_resp + 2);
 	if (credits == 0)
@@ -74,15 +73,13 @@ int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, __be32 *rdma_resp,
 		credits = r_xprt->rx_buf.rb_bc_max_requests;
 
 	spin_lock_bh(&xprt->transport_lock);
-	cwnd = xprt->cwnd;
 	xprt->cwnd = credits << RPC_CWNDSHIFT;
-	if (xprt->cwnd > cwnd)
-		xprt_release_rqst_cong(req->rq_task);
 	spin_unlock_bh(&xprt->transport_lock);
 
-
+	spin_lock(&xprt->queue_lock);
 	ret = 0;
 	xprt_complete_rqst(req->rq_task, rcvbuf->len);
+	xprt_unpin_rqst(req);
 	rcvbuf->len = 0;
 
 out_unlock:
@@ -251,7 +248,6 @@ xprt_rdma_bc_put(struct rpc_xprt *xprt)
 	dprintk("svcrdma: %s: xprt %p\n", __func__, xprt);
 
 	xprt_free(xprt);
-	module_put(THIS_MODULE);
 }
 
 static const struct rpc_xprt_ops xprt_rdma_bc_procs = {
@@ -323,20 +319,9 @@ xprt_setup_rdma_bc(struct xprt_create *args)
 	args->bc_xprt->xpt_bc_xprt = xprt;
 	xprt->bc_xprt = args->bc_xprt;
 
-	if (!try_module_get(THIS_MODULE))
-		goto out_fail;
-
 	/* Final put for backchannel xprt is in __svc_rdma_free */
 	xprt_get(xprt);
 	return xprt;
-
-out_fail:
-	xprt_rdma_free_addresses(xprt);
-	args->bc_xprt->xpt_bc_xprt = NULL;
-	args->bc_xprt->xpt_bc_xps = NULL;
-	xprt_put(xprt);
-	xprt_free(xprt);
-	return ERR_PTR(-EINVAL);
 }
 
 struct xprt_class xprt_rdma_bc = {
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 2848cafd4a17..2f7ec8912f49 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -475,10 +475,12 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 
 	/* Qualify the transport resource defaults with the
 	 * capabilities of this particular device */
-	newxprt->sc_max_send_sges = dev->attrs.max_send_sge;
-	/* transport hdr, head iovec, one page list entry, tail iovec */
-	if (newxprt->sc_max_send_sges < 4) {
-		pr_err("svcrdma: too few Send SGEs available (%d)\n",
+	/* Transport header, head iovec, tail iovec */
+	newxprt->sc_max_send_sges = 3;
+	/* Add one SGE per page list entry */
+	newxprt->sc_max_send_sges += svcrdma_max_req_size / PAGE_SIZE;
+	if (newxprt->sc_max_send_sges > dev->attrs.max_send_sge) {
+		pr_err("svcrdma: too few Send SGEs available (%d needed)\n",
 		       newxprt->sc_max_send_sges);
 		goto errout;
 	}