[PATCH] sunrpc: move bkl locking and xdr proc invocation into a common function

[Trond Myklebust]

On Tue, 2007-07-10 at 18:16 -0400, J. Bruce Fields wrote:
> From: J. Bruce Fields <bfields at citi.umich.edu>
> 
> Since every invocation of xdr encode or decode functions takes the BKL now,
> there's a lot of redundant lock_kernel/unlock_kernel pairs that we can pull out
> into a common function.
> 
> Signed-off-by: J. Bruce Fields <bfields at citi.umich.edu>
> ---
>  include/linux/sunrpc/xdr.h     |   11 +++++++++++
>  net/sunrpc/auth.c              |   12 ++----------
>  net/sunrpc/auth_gss/auth_gss.c |   20 +++++---------------
>  3 files changed, 18 insertions(+), 25 deletions(-)
> 
> Uh, I'm also starting to feel kind of ridiculous adding these
> lock_kernel/unlock_kernel's everywhere--at some point it seems better
> just to do them all in one place.  But tastes differ, so I figured I'd
> leave this change separate.  It could be folded into the previous patch
> if that seems better....

It's fine to keep it as a separate patch, but you're going to have to do
something about the name: do_xdrproc() breaks with the standard sunrpc
namespace conventions. How about naming it rpc_call_xdrproc().

Trond

> 
> --b.
> 
> diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
> index 9e340fa..594e501 100644
> --- a/include/linux/sunrpc/xdr.h
> +++ b/include/linux/sunrpc/xdr.h
> @@ -12,6 +12,7 @@
>  #include <linux/uio.h>
>  #include <asm/byteorder.h>
>  #include <linux/scatterlist.h>
> +#include <linux/smp_lock.h>
>  
>  /*
>   * Buffer adjustment
> @@ -35,6 +36,16 @@ struct xdr_netobj {
>   */
>  typedef int	(*kxdrproc_t)(void *rqstp, __be32 *data, void *obj);
>  
> +static inline int do_xdrproc(kxdrproc_t xdrproc, void *rqstp, __be32 *data, void *obj)
> +{
> +	int ret;
> +
> +	lock_kernel();
> +	ret = xdrproc(rqstp, data, obj);
> +	unlock_kernel();
> +	return ret;
> +}
> +
>  /*
>   * Basic structure for transmission/reception of a client XDR message.
>   * Features a header (for a linear buffer containing RPC headers
> diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
> index e04da66..6ad83c1 100644
> --- a/net/sunrpc/auth.c
> +++ b/net/sunrpc/auth.c
> @@ -359,17 +359,13 @@ rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
>  		__be32 *data, void *obj)
>  {
>  	struct rpc_cred *cred = task->tk_msg.rpc_cred;
> -	int ret;
>  
>  	dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
>  			task->tk_pid, cred->cr_ops->cr_name, cred);
>  	if (cred->cr_ops->crwrap_req)
>  		return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
>  	/* By default, we encode the arguments normally. */
> -	lock_kernel();
> -	ret = encode(rqstp, data, obj);
> -	unlock_kernel();
> -	return ret;
> +	return do_xdrproc(encode, rqstp, data, obj);
>  }
>  
>  int
> @@ -377,7 +373,6 @@ rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
>  		__be32 *data, void *obj)
>  {
>  	struct rpc_cred *cred = task->tk_msg.rpc_cred;
> -	int ret;
>  
>  	dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
>  			task->tk_pid, cred->cr_ops->cr_name, cred);
> @@ -385,10 +380,7 @@ rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
>  		return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
>  						   data, obj);
>  	/* By default, we decode the arguments normally. */
> -	lock_kernel();
> -	ret = decode(rqstp, data, obj);
> -	unlock_kernel();
> -	return ret;
> +	return do_xdrproc(decode, rqstp, data, obj);
>  }
>  
>  int
> diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
> index a001973..35d5dc9 100644
> --- a/net/sunrpc/auth_gss/auth_gss.c
> +++ b/net/sunrpc/auth_gss/auth_gss.c
> @@ -917,9 +917,7 @@ gss_wrap_req_integ(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
>  	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
>  	*p++ = htonl(rqstp->rq_seqno);
>  
> -	lock_kernel();
> -	status = encode(rqstp, p, obj);
> -	unlock_kernel();
> +	status = do_xdrproc(encode, rqstp, p, obj);
>  	if (status)
>  		return status;
>  
> @@ -1013,9 +1011,7 @@ gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
>  	offset = (u8 *)p - (u8 *)snd_buf->head[0].iov_base;
>  	*p++ = htonl(rqstp->rq_seqno);
>  
> -	lock_kernel();
> -	status = encode(rqstp, p, obj);
> -	unlock_kernel();
> +	status = do_xdrproc(encode, rqstp, p, obj);
>  	if (status)
>  		return status;
>  
> @@ -1074,16 +1070,12 @@ gss_wrap_req(struct rpc_task *task,
>  		/* The spec seems a little ambiguous here, but I think that not
>  		 * wrapping context destruction requests makes the most sense.
>  		 */
> -		lock_kernel();
> -		status = encode(rqstp, p, obj);
> -		unlock_kernel();
> +		status = do_xdrproc(encode, rqstp, p, obj);
>  		goto out;
>  	}
>  	switch (gss_cred->gc_service) {
>  		case RPC_GSS_SVC_NONE:
> -			lock_kernel();
> -			status = encode(rqstp, p, obj);
> -			unlock_kernel();
> +			status = do_xdrproc(encode, rqstp, p, obj);
>  			break;
>  		case RPC_GSS_SVC_INTEGRITY:
>  			status = gss_wrap_req_integ(cred, ctx, encode,
> @@ -1199,9 +1191,7 @@ gss_unwrap_resp(struct rpc_task *task,
>  	task->tk_auth->au_rslack = task->tk_auth->au_verfsize + (p - savedp)
>  						+ (savedlen - head->iov_len);
>  out_decode:
> -	lock_kernel();
> -	status = decode(rqstp, p, obj);
> -	unlock_kernel();
> +	status = do_xdrproc(decode, rqstp, p, obj);
>  out:
>  	gss_put_ctx(ctx);
>  	dprintk("RPC: %5u gss_unwrap_resp returning %d\n", task->tk_pid,