NFS: Reduce stack use in encode_exchange_id()

encode_exchange_id() uses more stack space than necessary, giving a compile
time warning. Reduce the size of the static buffer for implementation name.

Signed-off-by: Jim Rees <rees@umich.edu>
Reviewed-by: "Adamson, Dros" <Weston.Adamson@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 40836ee5dc3a..142aacb92459 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -270,6 +270,8 @@ static int nfs4_stat_to_errno(int);
 
 #if defined(CONFIG_NFS_V4_1)
 #define NFS4_MAX_MACHINE_NAME_LEN (64)
+#define IMPL_NAME_LIMIT (sizeof(utsname()->sysname) + sizeof(utsname()->release) + \
+                         sizeof(utsname()->version) + sizeof(utsname()->machine) + 8)
 
 #define encode_exchange_id_maxsz (op_encode_hdr_maxsz + \
                                 encode_verifier_maxsz + \
@@ -282,7 +284,7 @@ static int nfs4_stat_to_errno(int);
                                 1 /* nii_domain */ + \
                                 XDR_QUADLEN(NFS4_OPAQUE_LIMIT) + \
                                 1 /* nii_name */ + \
-                                XDR_QUADLEN(NFS4_OPAQUE_LIMIT) + \
+                                XDR_QUADLEN(IMPL_NAME_LIMIT) + \
                                 3 /* nii_date */)
 #define decode_exchange_id_maxsz (op_decode_hdr_maxsz + \
                                 2 /* eir_clientid */ + \
@@ -1713,7 +1715,7 @@ static void encode_exchange_id(struct xdr_stream *xdr,
                                struct compound_hdr *hdr)
 {
         __be32 *p;
-        char impl_name[NFS4_OPAQUE_LIMIT];
+        char impl_name[IMPL_NAME_LIMIT];
         int len = 0;
 
         encode_op_hdr(xdr, OP_EXCHANGE_ID, decode_exchange_id_maxsz, hdr);
@@ -1728,7 +1730,7 @@ static void encode_exchange_id(struct xdr_stream *xdr,
         if (send_implementation_id &&
             sizeof(CONFIG_NFS_V4_1_IMPLEMENTATION_ID_DOMAIN) > 1 &&
             sizeof(CONFIG_NFS_V4_1_IMPLEMENTATION_ID_DOMAIN)
-                <= NFS4_OPAQUE_LIMIT + 1)
+                <= sizeof(impl_name) + 1)
                 len = snprintf(impl_name, sizeof(impl_name), "%s %s %s %s",
                                utsname()->sysname, utsname()->release,
                                utsname()->version, utsname()->machine);