SUNRPC create an iterator to list only OFFLINE xprts

Create a new iterator helper that will go thru the all the transports
in the switch and return transports that are marked OFFLINE.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/include/linux/sunrpc/xprtmultipath.h b/include/linux/sunrpc/xprtmultipath.h
index bbb8a5fa08163a3ace88e0b23c384075d99117ac..688ca7eb1d0186b10d6cd08bb4a9b10efb4317a1 100644 (file)
--- a/include/linux/sunrpc/xprtmultipath.h
+++ b/include/linux/sunrpc/xprtmultipath.h
@@ -63,6 +63,9 @@ extern void xprt_iter_init(struct rpc_xprt_iter *xpi,
 extern void xprt_iter_init_listall(struct rpc_xprt_iter *xpi,
                struct rpc_xprt_switch *xps);
 
+extern void xprt_iter_init_listoffline(struct rpc_xprt_iter *xpi,
+               struct rpc_xprt_switch *xps);
+
 extern void xprt_iter_destroy(struct rpc_xprt_iter *xpi);
 
 extern struct rpc_xprt_switch *xprt_iter_xchg_switch(

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 2b079c4d8af10dbf62645a4e292c1d7e72e629f9..68021b70340dd67a6fbb275690c7396a0af3821a 100644 (file)
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -786,7 +786,8 @@ out_revert:
 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
 
 static
-int rpc_clnt_xprt_iter_init(struct rpc_clnt *clnt, struct rpc_xprt_iter *xpi)
+int _rpc_clnt_xprt_iter_init(struct rpc_clnt *clnt, struct rpc_xprt_iter *xpi,
+                            void func(struct rpc_xprt_iter *xpi, struct rpc_xprt_switch *xps))
 {
        struct rpc_xprt_switch *xps;
 
@@ -795,11 +796,17 @@ int rpc_clnt_xprt_iter_init(struct rpc_clnt *clnt, struct rpc_xprt_iter *xpi)
        rcu_read_unlock();
        if (xps == NULL)
                return -EAGAIN;
-       xprt_iter_init_listall(xpi, xps);
+       func(xpi, xps);
        xprt_switch_put(xps);
        return 0;
 }
 
+static
+int rpc_clnt_xprt_iter_init(struct rpc_clnt *clnt, struct rpc_xprt_iter *xpi)
+{
+       return _rpc_clnt_xprt_iter_init(clnt, xpi, xprt_iter_init_listall);
+}
+
 /**
  * rpc_clnt_iterate_for_each_xprt - Apply a function to all transports
  * @clnt: pointer to client

diff --git a/net/sunrpc/xprtmultipath.c b/net/sunrpc/xprtmultipath.c
index 1693f81aae376342660f4b2da08ae32b40355298..8def8423fc0af9b516301cf1f55857972c199186 100644 (file)
--- a/net/sunrpc/xprtmultipath.c
+++ b/net/sunrpc/xprtmultipath.c
@@ -27,6 +27,7 @@ typedef struct rpc_xprt *(*xprt_switch_find_xprt_t)(struct rpc_xprt_switch *xps,
 static const struct rpc_xprt_iter_ops rpc_xprt_iter_singular;
 static const struct rpc_xprt_iter_ops rpc_xprt_iter_roundrobin;
 static const struct rpc_xprt_iter_ops rpc_xprt_iter_listall;
+static const struct rpc_xprt_iter_ops rpc_xprt_iter_listoffline;
 
 static void xprt_switch_add_xprt_locked(struct rpc_xprt_switch *xps,
                struct rpc_xprt *xprt)
@@ -248,6 +249,18 @@ struct rpc_xprt *xprt_switch_find_first_entry(struct list_head *head)
        return NULL;
 }
 
+static
+struct rpc_xprt *xprt_switch_find_first_entry_offline(struct list_head *head)
+{
+       struct rpc_xprt *pos;
+
+       list_for_each_entry_rcu(pos, head, xprt_switch) {
+               if (!xprt_is_active(pos))
+                       return pos;
+       }
+       return NULL;
+}
+
 static
 struct rpc_xprt *xprt_iter_first_entry(struct rpc_xprt_iter *xpi)
 {
@@ -259,8 +272,9 @@ struct rpc_xprt *xprt_iter_first_entry(struct rpc_xprt_iter *xpi)
 }
 
 static
-struct rpc_xprt *xprt_switch_find_current_entry(struct list_head *head,
-               const struct rpc_xprt *cur)
+struct rpc_xprt *_xprt_switch_find_current_entry(struct list_head *head,
+                                                const struct rpc_xprt *cur,
+                                                bool find_active)
 {
        struct rpc_xprt *pos;
        bool found = false;
@@ -268,14 +282,25 @@ struct rpc_xprt *xprt_switch_find_current_entry(struct list_head *head,
        list_for_each_entry_rcu(pos, head, xprt_switch) {
                if (cur == pos)
                        found = true;
-               if (found && xprt_is_active(pos))
+               if (found && ((find_active && xprt_is_active(pos)) ||
+                             (!find_active && xprt_is_active(pos))))
                        return pos;
        }
        return NULL;
 }
 
 static
-struct rpc_xprt *xprt_iter_current_entry(struct rpc_xprt_iter *xpi)
+struct rpc_xprt *xprt_switch_find_current_entry(struct list_head *head,
+                                               const struct rpc_xprt *cur)
+{
+       return _xprt_switch_find_current_entry(head, cur, true);
+}
+
+static
+struct rpc_xprt * _xprt_iter_current_entry(struct rpc_xprt_iter *xpi,
+               struct rpc_xprt *first_entry(struct list_head *head),
+               struct rpc_xprt *current_entry(struct list_head *head,
+                                              const struct rpc_xprt *cur))
 {
        struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch);
        struct list_head *head;
@@ -284,8 +309,30 @@ struct rpc_xprt *xprt_iter_current_entry(struct rpc_xprt_iter *xpi)
                return NULL;
        head = &xps->xps_xprt_list;
        if (xpi->xpi_cursor == NULL || xps->xps_nxprts < 2)
-               return xprt_switch_find_first_entry(head);
-       return xprt_switch_find_current_entry(head, xpi->xpi_cursor);
+               return first_entry(head);
+       return current_entry(head, xpi->xpi_cursor);
+}
+
+static
+struct rpc_xprt *xprt_iter_current_entry(struct rpc_xprt_iter *xpi)
+{
+       return _xprt_iter_current_entry(xpi, xprt_switch_find_first_entry,
+                       xprt_switch_find_current_entry);
+}
+
+static
+struct rpc_xprt *xprt_switch_find_current_entry_offline(struct list_head *head,
+               const struct rpc_xprt *cur)
+{
+       return _xprt_switch_find_current_entry(head, cur, false);
+}
+
+static
+struct rpc_xprt *xprt_iter_current_entry_offline(struct rpc_xprt_iter *xpi)
+{
+       return _xprt_iter_current_entry(xpi,
+                       xprt_switch_find_first_entry_offline,
+                       xprt_switch_find_current_entry_offline);
 }
 
 bool rpc_xprt_switch_has_addr(struct rpc_xprt_switch *xps,
@@ -310,7 +357,7 @@ bool rpc_xprt_switch_has_addr(struct rpc_xprt_switch *xps,
 
 static
 struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head,
-               const struct rpc_xprt *cur)
+               const struct rpc_xprt *cur, bool check_active)
 {
        struct rpc_xprt *pos, *prev = NULL;
        bool found = false;
@@ -318,7 +365,12 @@ struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head,
        list_for_each_entry_rcu(pos, head, xprt_switch) {
                if (cur == prev)
                        found = true;
-               if (found && xprt_is_active(pos))
+               /* for request to return active transports return only
+                * active, for request to return offline transports
+                * return only offline
+                */
+               if (found && ((check_active && xprt_is_active(pos)) ||
+                             (!check_active && !xprt_is_active(pos))))
                        return pos;
                prev = pos;
        }
@@ -355,7 +407,7 @@ struct rpc_xprt *__xprt_switch_find_next_entry_roundrobin(struct list_head *head
 {
        struct rpc_xprt *ret;
 
-       ret = xprt_switch_find_next_entry(head, cur);
+       ret = xprt_switch_find_next_entry(head, cur, true);
        if (ret != NULL)
                return ret;
        return xprt_switch_find_first_entry(head);
@@ -397,7 +449,14 @@ static
 struct rpc_xprt *xprt_switch_find_next_entry_all(struct rpc_xprt_switch *xps,
                const struct rpc_xprt *cur)
 {
-       return xprt_switch_find_next_entry(&xps->xps_xprt_list, cur);
+       return xprt_switch_find_next_entry(&xps->xps_xprt_list, cur, true);
+}
+
+static
+struct rpc_xprt *xprt_switch_find_next_entry_offline(struct rpc_xprt_switch *xps,
+               const struct rpc_xprt *cur)
+{
+       return xprt_switch_find_next_entry(&xps->xps_xprt_list, cur, false);
 }
 
 static
@@ -407,6 +466,13 @@ struct rpc_xprt *xprt_iter_next_entry_all(struct rpc_xprt_iter *xpi)
                        xprt_switch_find_next_entry_all);
 }
 
+static
+struct rpc_xprt *xprt_iter_next_entry_offline(struct rpc_xprt_iter *xpi)
+{
+       return xprt_iter_next_entry_multiple(xpi,
+                       xprt_switch_find_next_entry_offline);
+}
+
 /*
  * xprt_iter_rewind - Resets the xprt iterator
  * @xpi: pointer to rpc_xprt_iter
@@ -460,6 +526,12 @@ void xprt_iter_init_listall(struct rpc_xprt_iter *xpi,
        __xprt_iter_init(xpi, xps, &rpc_xprt_iter_listall);
 }
 
+void xprt_iter_init_listoffline(struct rpc_xprt_iter *xpi,
+               struct rpc_xprt_switch *xps)
+{
+       __xprt_iter_init(xpi, xps, &rpc_xprt_iter_listoffline);
+}
+
 /**
  * xprt_iter_xchg_switch - Atomically swap out the rpc_xprt_switch
  * @xpi: pointer to rpc_xprt_iter
@@ -574,3 +646,10 @@ const struct rpc_xprt_iter_ops rpc_xprt_iter_listall = {
        .xpi_xprt = xprt_iter_current_entry,
        .xpi_next = xprt_iter_next_entry_all,
 };
+
+static
+const struct rpc_xprt_iter_ops rpc_xprt_iter_listoffline = {
+       .xpi_rewind = xprt_iter_default_rewind,
+       .xpi_xprt = xprt_iter_current_entry_offline,
+       .xpi_next = xprt_iter_next_entry_offline,
+};