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
  ...

1 files changed, 14 insertions, 39 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index db8bb6b3a2b0..3b525accaa68 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -325,59 +325,34 @@ static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
 /*
  * Generic recvfrom routine.
  */
-static int svc_recvfrom(struct svc_rqst *rqstp, struct kvec *iov, int nr,
-			int buflen)
+static ssize_t svc_recvfrom(struct svc_rqst *rqstp, struct kvec *iov,
+			    unsigned int nr, size_t buflen, unsigned int base)
 {
 	struct svc_sock *svsk =
 		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
-	struct msghdr msg = {
-		.msg_flags	= MSG_DONTWAIT,
-	};
-	int len;
+	struct msghdr msg = { NULL };
+	ssize_t len;
 
 	rqstp->rq_xprt_hlen = 0;
 
 	clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
 	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, iov, nr, buflen);
-	len = sock_recvmsg(svsk->sk_sock, &msg, msg.msg_flags);
+	if (base != 0) {
+		iov_iter_advance(&msg.msg_iter, base);
+		buflen -= base;
+	}
+	len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
 	/* If we read a full record, then assume there may be more
 	 * data to read (stream based sockets only!)
 	 */
 	if (len == buflen)
 		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
 
-	dprintk("svc: socket %p recvfrom(%p, %zu) = %d\n",
+	dprintk("svc: socket %p recvfrom(%p, %zu) = %zd\n",
 		svsk, iov[0].iov_base, iov[0].iov_len, len);
 	return len;
 }
 
-static int svc_partial_recvfrom(struct svc_rqst *rqstp,
-				struct kvec *iov, int nr,
-				int buflen, unsigned int base)
-{
-	size_t save_iovlen;
-	void *save_iovbase;
-	unsigned int i;
-	int ret;
-
-	if (base == 0)
-		return svc_recvfrom(rqstp, iov, nr, buflen);
-
-	for (i = 0; i < nr; i++) {
-		if (iov[i].iov_len > base)
-			break;
-		base -= iov[i].iov_len;
-	}
-	save_iovlen = iov[i].iov_len;
-	save_iovbase = iov[i].iov_base;
-	iov[i].iov_len -= base;
-	iov[i].iov_base += base;
-	ret = svc_recvfrom(rqstp, &iov[i], nr - i, buflen);
-	iov[i].iov_len = save_iovlen;
-	iov[i].iov_base = save_iovbase;
-	return ret;
-}
-
 /*
  * Set socket snd and rcv buffer lengths
  */
@@ -962,7 +937,8 @@ static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
 		want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
 		iov.iov_base = ((char *) &svsk->sk_reclen) + svsk->sk_tcplen;
 		iov.iov_len  = want;
-		if ((len = svc_recvfrom(rqstp, &iov, 1, want)) < 0)
+		len = svc_recvfrom(rqstp, &iov, 1, want, 0);
+		if (len < 0)
 			goto error;
 		svsk->sk_tcplen += len;
 
@@ -1088,14 +1064,13 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
 
 	vec = rqstp->rq_vec;
 
-	pnum = copy_pages_to_kvecs(&vec[0], &rqstp->rq_pages[0],
-						svsk->sk_datalen + want);
+	pnum = copy_pages_to_kvecs(&vec[0], &rqstp->rq_pages[0], base + want);
 
 	rqstp->rq_respages = &rqstp->rq_pages[pnum];
 	rqstp->rq_next_page = rqstp->rq_respages + 1;
 
 	/* Now receive data */
-	len = svc_partial_recvfrom(rqstp, vec, pnum, want, base);
+	len = svc_recvfrom(rqstp, vec, pnum, base + want, base);
 	if (len >= 0) {
 		svsk->sk_tcplen += len;
 		svsk->sk_datalen += len;