Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

[cascardo/linux.git] / net / sunrpc / svc_xprt.c

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 4f01f63..c3f6523 100644 (file)
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -21,6 +21,10 @@
 
 #define RPCDBG_FACILITY        RPCDBG_SVCXPRT
 
+static unsigned int svc_rpc_per_connection_limit __read_mostly;
+module_param(svc_rpc_per_connection_limit, uint, 0644);
+
+
 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);
@@ -329,12 +333,45 @@ char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
 }
 EXPORT_SYMBOL_GPL(svc_print_addr);
 
+static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
+{
+       unsigned int limit = svc_rpc_per_connection_limit;
+       int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
+
+       return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
+}
+
+static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
+{
+       if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
+               if (!svc_xprt_slots_in_range(xprt))
+                       return false;
+               atomic_inc(&xprt->xpt_nr_rqsts);
+               set_bit(RQ_DATA, &rqstp->rq_flags);
+       }
+       return true;
+}
+
+static void svc_xprt_release_slot(struct svc_rqst *rqstp)
+{
+       struct svc_xprt *xprt = rqstp->rq_xprt;
+       if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
+               atomic_dec(&xprt->xpt_nr_rqsts);
+               svc_xprt_enqueue(xprt);
+       }
+}
+
 static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
 {
        if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
                return true;
-       if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED)))
-               return xprt->xpt_ops->xpo_has_wspace(xprt);
+       if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) {
+               if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
+                   svc_xprt_slots_in_range(xprt))
+                       return true;
+               trace_svc_xprt_no_write_space(xprt);
+               return false;
+       }
        return false;
 }
 
@@ -480,8 +517,6 @@ void svc_reserve(struct svc_rqst *rqstp, int space)
                atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
                rqstp->rq_reserved = space;
 
-               if (xprt->xpt_ops->xpo_adjust_wspace)
-                       xprt->xpt_ops->xpo_adjust_wspace(xprt);
                svc_xprt_enqueue(xprt);
        }
 }
@@ -512,8 +547,8 @@ static void svc_xprt_release(struct svc_rqst *rqstp)
 
        rqstp->rq_res.head[0].iov_len = 0;
        svc_reserve(rqstp, 0);
+       svc_xprt_release_slot(rqstp);
        rqstp->rq_xprt = NULL;
-
        svc_xprt_put(xprt);
 }
 
@@ -781,7 +816,7 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
                        svc_add_new_temp_xprt(serv, newxpt);
                else
                        module_put(xprt->xpt_class->xcl_owner);
-       } else {
+       } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
                /* XPT_DATA|XPT_DEFERRED case: */
                dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
                        rqstp, rqstp->rq_pool->sp_id, xprt,
@@ -871,6 +906,7 @@ EXPORT_SYMBOL_GPL(svc_recv);
  */
 void svc_drop(struct svc_rqst *rqstp)
 {
+       trace_svc_drop(rqstp);
        dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
        svc_xprt_release(rqstp);
 }
@@ -1148,6 +1184,7 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
                spin_unlock(&xprt->xpt_lock);
                dprintk("revisit canceled\n");
                svc_xprt_put(xprt);
+               trace_svc_drop_deferred(dr);
                kfree(dr);
                return;
        }
@@ -1205,6 +1242,7 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req)
        set_bit(RQ_DROPME, &rqstp->rq_flags);
 
        dr->handle.revisit = svc_revisit;
+       trace_svc_defer(rqstp);
        return &dr->handle;
 }
 
@@ -1245,6 +1283,7 @@ static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
                                struct svc_deferred_req,
                                handle.recent);
                list_del_init(&dr->handle.recent);
+               trace_svc_revisit_deferred(dr);
        } else
                clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
        spin_unlock(&xprt->xpt_lock);