nfsd41: sunrpc: Added rpc server-side backchannel handling

[GitHub/moto-9609/android_kernel_motorola_exynos9610.git] / net / sunrpc / svc_xprt.c

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index c200d92e57e4990c98d5f95ebff026104d5fdedc..df124f78ee489762f4a9028af3b95f38a90f34d3 100644 (file)
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -5,12 +5,14 @@
  */
 
 #include <linux/sched.h>
+#include <linux/smp_lock.h>
 #include <linux/errno.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <net/sock.h>
 #include <linux/sunrpc/stats.h>
 #include <linux/sunrpc/svc_xprt.h>
+#include <linux/sunrpc/svcsock.h>
 
 #define RPCDBG_FACILITY        RPCDBG_SVCXPRT
 
@@ -158,6 +160,7 @@ void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
        mutex_init(&xprt->xpt_mutex);
        spin_lock_init(&xprt->xpt_lock);
        set_bit(XPT_BUSY, &xprt->xpt_flags);
+       rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
 }
 EXPORT_SYMBOL_GPL(svc_xprt_init);
 
@@ -708,10 +711,7 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
        spin_unlock_bh(&pool->sp_lock);
 
        len = 0;
-       if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
-               dprintk("svc_recv: found XPT_CLOSE\n");
-               svc_delete_xprt(xprt);
-       } else if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
+       if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
                struct svc_xprt *newxpt;
                newxpt = xprt->xpt_ops->xpo_accept(xprt);
                if (newxpt) {
@@ -737,7 +737,7 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
                        svc_xprt_received(newxpt);
                }
                svc_xprt_received(xprt);
-       } else {
+       } else if (!test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
                dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
                        rqstp, pool->sp_id, xprt,
                        atomic_read(&xprt->xpt_ref.refcount));
@@ -750,6 +750,11 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
                dprintk("svc: got len=%d\n", len);
        }
 
+       if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
+               dprintk("svc_recv: found XPT_CLOSE\n");
+               svc_delete_xprt(xprt);
+       }
+
        /* No data, incomplete (TCP) read, or accept() */
        if (len == 0 || len == -EAGAIN) {
                rqstp->rq_res.len = 0;
@@ -806,6 +811,7 @@ int svc_send(struct svc_rqst *rqstp)
        else
                len = xprt->xpt_ops->xpo_sendto(rqstp);
        mutex_unlock(&xprt->xpt_mutex);
+       rpc_wake_up(&xprt->xpt_bc_pending);
        svc_xprt_release(rqstp);
 
        if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
@@ -1097,36 +1103,58 @@ struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
 }
 EXPORT_SYMBOL_GPL(svc_find_xprt);
 
-/*
- * Format a buffer with a list of the active transports. A zero for
- * the buflen parameter disables target buffer overflow checking.
+static int svc_one_xprt_name(const struct svc_xprt *xprt,
+                            char *pos, int remaining)
+{
+       int len;
+
+       len = snprintf(pos, remaining, "%s %u\n",
+                       xprt->xpt_class->xcl_name,
+                       svc_xprt_local_port(xprt));
+       if (len >= remaining)
+               return -ENAMETOOLONG;
+       return len;
+}
+
+/**
+ * svc_xprt_names - format a buffer with a list of transport names
+ * @serv: pointer to an RPC service
+ * @buf: pointer to a buffer to be filled in
+ * @buflen: length of buffer to be filled in
+ *
+ * Fills in @buf with a string containing a list of transport names,
+ * each name terminated with '\n'.
+ *
+ * Returns positive length of the filled-in string on success; otherwise
+ * a negative errno value is returned if an error occurs.
  */
-int svc_xprt_names(struct svc_serv *serv, char *buf, int buflen)
+int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
 {
        struct svc_xprt *xprt;
-       char xprt_str[64];
-       int totlen = 0;
-       int len;
+       int len, totlen;
+       char *pos;
 
        /* Sanity check args */
        if (!serv)
                return 0;
 
        spin_lock_bh(&serv->sv_lock);
+
+       pos = buf;
+       totlen = 0;
        list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
-               len = snprintf(xprt_str, sizeof(xprt_str),
-                              "%s %d\n", xprt->xpt_class->xcl_name,
-                              svc_xprt_local_port(xprt));
-               /* If the string was truncated, replace with error string */
-               if (len >= sizeof(xprt_str))
-                       strcpy(xprt_str, "name-too-long\n");
-               /* Don't overflow buffer */
-               len = strlen(xprt_str);
-               if (buflen && (len + totlen >= buflen))
+               len = svc_one_xprt_name(xprt, pos, buflen - totlen);
+               if (len < 0) {
+                       *buf = '\0';
+                       totlen = len;
+               }
+               if (len <= 0)
                        break;
-               strcpy(buf+totlen, xprt_str);
+
+               pos += len;
                totlen += len;
        }
+
        spin_unlock_bh(&serv->sv_lock);
        return totlen;
 }
@@ -1142,11 +1170,6 @@ static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
 
        dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
 
-       lock_kernel();
-       /* bump up the pseudo refcount while traversing */
-       svc_get(serv);
-       unlock_kernel();
-
        if (!pidx)
                return SEQ_START_TOKEN;
        return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
@@ -1174,12 +1197,6 @@ static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
 
 static void svc_pool_stats_stop(struct seq_file *m, void *p)
 {
-       struct svc_serv *serv = m->private;
-
-       lock_kernel();
-       /* this function really, really should have been called svc_put() */
-       svc_destroy(serv);
-       unlock_kernel();
 }
 
 static int svc_pool_stats_show(struct seq_file *m, void *p)