NLM: Shrink the maximum request size of NLM4 requests

NLM version 4 requests estimate the call and reply header sizes rather
conservatively, using the very maximum size allowed in the protocol even
though Linux always uses only a small fraction of the allowable space.

Reduce the size of caller and lock arguments to conserve RPC buffer space
while XDR encoding NLM4 arguments.  Add compile-time checks to ensure the
hostname string won't overflow NLM protocol maximums.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index ac25b5649c5..f6a81e0b1b9 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -88,7 +88,7 @@ struct nlm_wait;
 /*
  * Memory chunk for NLM client RPC request.
  */
-#define NLMCLNT_OHSIZE          (sizeof(utsname()->nodename)+10)
+#define NLMCLNT_OHSIZE          ((__NEW_UTS_LEN) + 10u)
 struct nlm_rqst {
         unsigned int            a_flags;        /* initial RPC task flags */
         struct nlm_host *       a_host;         /* host handle */