diff mbox

NFS: Reduce stack use in encode_exchange_id()

Message ID 1353101475-11613-1-git-send-email-rees@umich.edu (mailing list archive)
State New, archived
Headers show

Commit Message

Jim Rees Nov. 16, 2012, 9:31 p.m. UTC
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>
---
 fs/nfs/nfs4xdr.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Comments

Trond Myklebust Nov. 16, 2012, 9:59 p.m. UTC | #1
On Fri, 2012-11-16 at 16:31 -0500, Jim Rees wrote:
> 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>

> ---

>  fs/nfs/nfs4xdr.c |    7 +++++--

>  1 file changed, 5 insertions(+), 2 deletions(-)

> 

> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c

> index 672d9b0..e9c101d 100644

> --- a/fs/nfs/nfs4xdr.c

> +++ b/fs/nfs/nfs4xdr.c

> @@ -1706,12 +1706,15 @@ static void encode_bind_conn_to_session(struct xdr_stream *xdr,

>  	*p = 0;	/* use_conn_in_rdma_mode = False */

>  }

>  

> +#define IMPL_NAME_LIMIT (sizeof(utsname()->sysname) + sizeof(utsname()->release) + \

> +			 sizeof(utsname()->version) + sizeof(utsname()->machine) + 8)

> +

>  static void encode_exchange_id(struct xdr_stream *xdr,

>  			       struct nfs41_exchange_id_args *args,

>  			       struct compound_hdr *hdr)

>  {

>  	__be32 *p;

> -	char impl_name[NFS4_OPAQUE_LIMIT];

> +	char impl_name[IMPL_NAME_LIMIT];


Hmm... Shouldn't we also be changing encode_exchange_id_maxsz to mirror
this new buffer limit?

>  	int len = 0;

>  

>  	encode_op_hdr(xdr, OP_EXCHANGE_ID, decode_exchange_id_maxsz, hdr);

> @@ -1726,7 +1729,7 @@ 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);


-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com
Jim Rees Nov. 16, 2012, 10:25 p.m. UTC | #2
Myklebust, Trond wrote:

  Hmm... Shouldn't we also be changing encode_exchange_id_maxsz to mirror
  this new buffer limit?

Probably. I'll fix it. Thanks.
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diff mbox

Patch

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 672d9b0..e9c101d 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1706,12 +1706,15 @@  static void encode_bind_conn_to_session(struct xdr_stream *xdr,
 	*p = 0;	/* use_conn_in_rdma_mode = False */
 }
 
+#define IMPL_NAME_LIMIT (sizeof(utsname()->sysname) + sizeof(utsname()->release) + \
+			 sizeof(utsname()->version) + sizeof(utsname()->machine) + 8)
+
 static void encode_exchange_id(struct xdr_stream *xdr,
 			       struct nfs41_exchange_id_args *args,
 			       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);
@@ -1726,7 +1729,7 @@  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);