Merge tag 'nfsd-5.7' of git://git.linux-nfs.org/projects/cel/cel-2.6

Pull nfsd updates from Chuck Lever:

 - Fix EXCHANGE_ID response when NFSD runs in a container

 - A battery of new static trace points

 - Socket transports now use bio_vec to send Replies

 - NFS/RDMA now supports filesystems with no .splice_read method

 - Favor memcpy() over DMA mapping for small RPC/RDMA Replies

 - Add pre-requisites for supporting multiple Write chunks

 - Numerous minor fixes and clean-ups

[ Chuck is filling in for Bruce this time while he and his family settle
  into a new house ]

* tag 'nfsd-5.7' of git://git.linux-nfs.org/projects/cel/cel-2.6: (39 commits)
  svcrdma: Fix leak of transport addresses
  SUNRPC: Fix a potential buffer overflow in 'svc_print_xprts()'
  SUNRPC/cache: don't allow invalid entries to be flushed
  nfsd: fsnotify on rmdir under nfsd/clients/
  nfsd4: kill warnings on testing stateids with mismatched clientids
  nfsd: remove read permission bit for ctl sysctl
  NFSD: Fix NFS server build errors
  sunrpc: Add tracing for cache events
  SUNRPC/cache: Allow garbage collection of invalid cache entries
  nfsd: export upcalls must not return ESTALE when mountd is down
  nfsd: Add tracepoints for update of the expkey and export cache entries
  nfsd: Add tracepoints for exp_find_key() and exp_get_by_name()
  nfsd: Add tracing to nfsd_set_fh_dentry()
  nfsd: Don't add locks to closed or closing open stateids
  SUNRPC: Teach server to use xprt_sock_sendmsg for socket sends
  SUNRPC: Refactor xs_sendpages()
  svcrdma: Avoid DMA mapping small RPC Replies
  svcrdma: Fix double sync of transport header buffer
  svcrdma: Refactor chunk list encoders
  SUNRPC: Add encoders for list item discriminators
  ...

1 files changed, 6 insertions, 5 deletions

diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 89bd5581f317..963800037609 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -152,12 +152,13 @@ static int nfs_dns_upcall(struct cache_detail *cd,
 		struct cache_head *ch)
 {
 	struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
-	int ret;
 
-	ret = nfs_cache_upcall(cd, key->hostname);
-	if (ret)
-		ret = sunrpc_cache_pipe_upcall(cd, ch);
-	return ret;
+	if (test_and_set_bit(CACHE_PENDING, &ch->flags))
+		return 0;
+	if (!nfs_cache_upcall(cd, key->hostname))
+		return 0;
+	clear_bit(CACHE_PENDING, &ch->flags);
+	return sunrpc_cache_pipe_upcall_timeout(cd, ch);
 }
 
 static int nfs_dns_match(struct cache_head *ca,