svc: Make deferral processing xprt independent

This patch moves the transport independent sk_deferred list to the svc_xprt
structure and updates the svc_deferred_req structure to keep pointers to
svc_xprt's directly. The deferral processing code is also moved out of the
transport dependent recvfrom functions and into the generic svc_recv path.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

5 files changed, 29 insertions, 36 deletions

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index cfb2652f6f8f..40adc9d75a6d 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -320,7 +320,7 @@ static inline void svc_free_res_pages(struct svc_rqst *rqstp)
 
 struct svc_deferred_req {
         u32                     prot;   /* protocol (UDP or TCP) */
-        struct svc_sock         *svsk;
+        struct svc_xprt         *xprt;
         struct sockaddr_storage addr;   /* where reply must go */
         size_t                  addrlen;
         union svc_addr_u        daddr;  /* where reply must come from */
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 1b5da39bb461..6a8445b9dfd9 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -59,6 +59,8 @@ struct svc_xprt {
         spinlock_t              xpt_lock;       /* protects sk_deferred
                                                  * and xpt_auth_cache */
         void                    *xpt_auth_cache;/* auth cache */
+        struct list_head        xpt_deferred;   /* deferred requests that need
+                                                 * to be revisted */
 };
 
 int     svc_reg_xprt_class(struct svc_xprt_class *);
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index f2ed6a25a7aa..96a229e6b9c9 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -20,9 +20,6 @@ struct svc_sock {
         struct socket *         sk_sock;        /* berkeley socket layer */
         struct sock *           sk_sk;          /* INET layer */
 
-        struct list_head        sk_deferred;    /* deferred requests that need to
-                                                 * be revisted */
-
         /* We keep the old state_change and data_ready CB's here */
         void                    (*sk_ostate)(struct sock *);
         void                    (*sk_odata)(struct sock *, int bytes);
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index d2ac130b9040..023aeb0ecfa9 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -102,6 +102,7 @@ void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
         xprt->xpt_server = serv;
         INIT_LIST_HEAD(&xprt->xpt_list);
         INIT_LIST_HEAD(&xprt->xpt_ready);
+        INIT_LIST_HEAD(&xprt->xpt_deferred);
         mutex_init(&xprt->xpt_mutex);
         spin_lock_init(&xprt->xpt_lock);
 }
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 5c9422c9a980..9d0a9e6c0e10 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -89,7 +89,7 @@ static void		svc_close_xprt(struct svc_xprt *xprt);
 static void             svc_sock_detach(struct svc_xprt *);
 static void             svc_sock_free(struct svc_xprt *);
 
-static struct svc_deferred_req *svc_deferred_dequeue(struct svc_sock *svsk);
+static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
 static int svc_deferred_recv(struct svc_rqst *rqstp);
 static struct cache_deferred_req *svc_defer(struct cache_req *req);
 static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
@@ -771,11 +771,6 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
                                 (serv->sv_nrthreads+3) * serv->sv_max_mesg,
                                 (serv->sv_nrthreads+3) * serv->sv_max_mesg);
 
-        if ((rqstp->rq_deferred = svc_deferred_dequeue(svsk))) {
-                svc_xprt_received(&svsk->sk_xprt);
-                return svc_deferred_recv(rqstp);
-        }
-
         clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
         skb = NULL;
         err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
@@ -1138,11 +1133,6 @@ svc_tcp_recvfrom(struct svc_rqst *rqstp)
                 test_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags),
                 test_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags));
 
-        if ((rqstp->rq_deferred = svc_deferred_dequeue(svsk))) {
-                svc_xprt_received(&svsk->sk_xprt);
-                return svc_deferred_recv(rqstp);
-        }
-
         if (test_and_clear_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags))
                 /* sndbuf needs to have room for one request
                  * per thread, otherwise we can stall even when the
@@ -1601,7 +1591,12 @@ svc_recv(struct svc_rqst *rqstp, long timeout)
                 dprintk("svc: server %p, pool %u, socket %p, inuse=%d\n",
                         rqstp, pool->sp_id, svsk,
                         atomic_read(&svsk->sk_xprt.xpt_ref.refcount));
-                len = svsk->sk_xprt.xpt_ops->xpo_recvfrom(rqstp);
+                rqstp->rq_deferred = svc_deferred_dequeue(&svsk->sk_xprt);
+                if (rqstp->rq_deferred) {
+                        svc_xprt_received(&svsk->sk_xprt);
+                        len = svc_deferred_recv(rqstp);
+                } else
+                        len = svsk->sk_xprt.xpt_ops->xpo_recvfrom(rqstp);
                 dprintk("svc: got len=%d\n", len);
         }
 
@@ -1758,7 +1753,6 @@ static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
         svsk->sk_ostate = inet->sk_state_change;
         svsk->sk_odata = inet->sk_data_ready;
         svsk->sk_owspace = inet->sk_write_space;
-        INIT_LIST_HEAD(&svsk->sk_deferred);
 
         /* Initialize the socket */
         if (sock->type == SOCK_DGRAM)
@@ -1976,22 +1970,21 @@ void svc_close_all(struct list_head *xprt_list)
 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
 {
         struct svc_deferred_req *dr = container_of(dreq, struct svc_deferred_req, handle);
-        struct svc_sock *svsk;
+        struct svc_xprt *xprt = dr->xprt;
 
         if (too_many) {
-                svc_xprt_put(&dr->svsk->sk_xprt);
+                svc_xprt_put(xprt);
                 kfree(dr);
                 return;
         }
         dprintk("revisit queued\n");
-        svsk = dr->svsk;
-        dr->svsk = NULL;
-        spin_lock(&svsk->sk_xprt.xpt_lock);
-        list_add(&dr->handle.recent, &svsk->sk_deferred);
-        spin_unlock(&svsk->sk_xprt.xpt_lock);
-        set_bit(XPT_DEFERRED, &svsk->sk_xprt.xpt_flags);
-        svc_xprt_enqueue(&svsk->sk_xprt);
-        svc_xprt_put(&svsk->sk_xprt);
+        dr->xprt = NULL;
+        spin_lock(&xprt->xpt_lock);
+        list_add(&dr->handle.recent, &xprt->xpt_deferred);
+        spin_unlock(&xprt->xpt_lock);
+        set_bit(XPT_DEFERRED, &xprt->xpt_flags);
+        svc_xprt_enqueue(xprt);
+        svc_xprt_put(xprt);
 }
 
 static struct cache_deferred_req *
@@ -2022,7 +2015,7 @@ svc_defer(struct cache_req *req)
                 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base-skip, dr->argslen<<2);
         }
         svc_xprt_get(rqstp->rq_xprt);
-        dr->svsk = rqstp->rq_sock;
+        dr->xprt = rqstp->rq_xprt;
 
         dr->handle.revisit = svc_revisit;
         return &dr->handle;
@@ -2048,21 +2041,21 @@ static int svc_deferred_recv(struct svc_rqst *rqstp)
 }
 
 
-static struct svc_deferred_req *svc_deferred_dequeue(struct svc_sock *svsk)
+static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
 {
         struct svc_deferred_req *dr = NULL;
 
-        if (!test_bit(XPT_DEFERRED, &svsk->sk_xprt.xpt_flags))
+        if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
                 return NULL;
-        spin_lock(&svsk->sk_xprt.xpt_lock);
-        clear_bit(XPT_DEFERRED, &svsk->sk_xprt.xpt_flags);
-        if (!list_empty(&svsk->sk_deferred)) {
-                dr = list_entry(svsk->sk_deferred.next,
+        spin_lock(&xprt->xpt_lock);
+        clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
+        if (!list_empty(&xprt->xpt_deferred)) {
+                dr = list_entry(xprt->xpt_deferred.next,
                                 struct svc_deferred_req,
                                 handle.recent);
                 list_del_init(&dr->handle.recent);
-                set_bit(XPT_DEFERRED, &svsk->sk_xprt.xpt_flags);
+                set_bit(XPT_DEFERRED, &xprt->xpt_flags);
         }
-        spin_unlock(&svsk->sk_xprt.xpt_lock);
+        spin_unlock(&xprt->xpt_lock);
         return dr;
 }