SUNRPC: move bkl locking and xdr proc invocation into a common helper

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@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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 +36,21 @@ struct xdr_netobj {
  */
 typedef int	(*kxdrproc_t)(void *rqstp, __be32 *data, void *obj);
 
+/*
+ * We're still requiring the BKL in the xdr code until it's been
+ * more carefully audited, at which point this wrapper will become
+ * unnecessary.
+ */
+static inline int rpc_call_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

net/sunrpc/auth.c

@@ -13,7 +13,6 @@
 #include <linux/errno.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/spinlock.h>
-#include <linux/smp_lock.h>
 
 #ifdef RPC_DEBUG
 # define RPCDBG_FACILITY	RPCDBG_AUTH
@@ -476,17 +475,13 @@ 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();
+	return rpc_call_xdrproc(encode, rqstp, data, obj);
-	ret = encode(rqstp, data, obj);
-	unlock_kernel();
-	return ret;
 }
 
 int
@@ -494,7 +489,6 @@ 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);
@@ -502,10 +496,7 @@ 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();
+	return rpc_call_xdrproc(decode, rqstp, data, obj);
-	ret = decode(rqstp, data, obj);
-	unlock_kernel();
-	return ret;
 }
 
 int

net/sunrpc/auth_gss/auth_gss.c

@@ -43,7 +43,6 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
-#include <linux/smp_lock.h>
 #include <linux/pagemap.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/auth.h>
@@ -1000,9 +999,7 @@ 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 = rpc_call_xdrproc(encode, rqstp, p, obj);
-	status = encode(rqstp, p, obj);
-	unlock_kernel();
 	if (status)
 		return status;
 
@@ -1096,9 +1093,7 @@ 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 = rpc_call_xdrproc(encode, rqstp, p, obj);
-	status = encode(rqstp, p, obj);
-	unlock_kernel();
 	if (status)
 		return status;
 
@@ -1157,16 +1152,12 @@ 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 = rpc_call_xdrproc(encode, rqstp, p, obj);
-		status = encode(rqstp, p, obj);
-		unlock_kernel();
 		goto out;
 	}
 	switch (gss_cred->gc_service) {
 		case RPC_GSS_SVC_NONE:
-			lock_kernel();
+			status = rpc_call_xdrproc(encode, rqstp, p, obj);
-			status = encode(rqstp, p, obj);
-			unlock_kernel();
 			break;
 		case RPC_GSS_SVC_INTEGRITY:
 			status = gss_wrap_req_integ(cred, ctx, encode,
@@ -1282,9 +1273,7 @@ gss_unwrap_resp(struct rpc_task *task,
 	cred->cr_auth->au_rslack = cred->cr_auth->au_verfsize + (p - savedp)
 						+ (savedlen - head->iov_len);
 out_decode:
-	lock_kernel();
+	status = rpc_call_xdrproc(decode, rqstp, p, obj);
-	status = decode(rqstp, p, obj);
-	unlock_kernel();
 out:
 	gss_put_ctx(ctx);
 	dprintk("RPC: %5u gss_unwrap_resp returning %d\n", task->tk_pid,