[PATCH] PATCH 10/16: NFSD: TCP: rationalise locking in RPC server routines

Tidy up SMP locking for svc_sock

sk_lock is not necessary and is now removed.
The only things that were happening under sk_lock but
not the more global sv_lock were testing and setting
some of the flags: sk_busy, sk_conn, sk_data etc.

These have been changed to bits in a flags word which are atomically
set and tested.

Also, by establishing some simple rules about that must
be done after setting these flags, the locking is not needed.

With this patch sk_conn and sk_data are now flags, not counts (sk_data
was already a flag for udp).  They are set if there might be
a connection or data, and only clear when we are sure there aren't
(or when we are about to check if there is).

svc_sock_accepted becomes identical to svc_sock_recieved and
so is discarded in favour of the latter.

sk_rqstp was never used and is now gone.

include/linux/sunrpc/svcsock.h

@@ -19,17 +19,18 @@ struct svc_sock {
 	struct list_head	sk_list;	/* list of all sockets */
 	struct socket *		sk_sock;	/* berkeley socket layer */
 	struct sock *		sk_sk;		/* INET layer */
-	spinlock_t		sk_lock;
 
 	struct svc_serv *	sk_server;	/* service for this socket */
 	unsigned char		sk_inuse;	/* use count */
-	unsigned char		sk_busy;	/* enqueued/receiving */
-	unsigned char		sk_conn;	/* conn pending */
-	unsigned char		sk_close;	/* dead or dying */
-	int			sk_data;	/* data pending */
-	unsigned int		sk_temp : 1,	/* temp socket */
-				sk_qued : 1,	/* on serv->sk_sockets */
-				sk_dead : 1;	/* socket closed */
+	unsigned int		sk_flags;
+#define	SK_BUSY		0			/* enqueued/receiving */
+#define	SK_CONN		1			/* conn pending */
+#define	SK_CLOSE	2			/* dead or dying */
+#define	SK_DATA		3			/* data pending */
+#define	SK_TEMP		4			/* temp (TCP) socket */
+#define	SK_QUED		5			/* on serv->sk_sockets */
+#define	SK_DEAD		6			/* socket closed */
+
 	int			(*sk_recvfrom)(struct svc_rqst *rqstp);
 	int			(*sk_sendto)(struct svc_rqst *rqstp);
 
@@ -40,9 +41,6 @@ struct svc_sock {
 	/* private TCP part */
 	int			sk_reclen;	/* length of record */
 	int			sk_tcplen;	/* current read length */
-
-	/* Debugging */
-	struct svc_rqst *	sk_rqstp;
 };
 
 /*