[2/3] SUNRPC: Skip zero-refcount transports
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Message ID 20190716200433.38758-2-trond.myklebust@hammerspace.com
State New
Headers show
Series
  • [1/3] SUNRPC: Replace division by multiplication in calculation of queue length
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Commit Message

Trond Myklebust July 16, 2019, 8:04 p.m. UTC
When looking for the next transport to use for an RPC call, skip those
that are in the process of being destroyed and that have a zero refcount.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 net/sunrpc/xprtmultipath.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

Patch
diff mbox series

diff --git a/net/sunrpc/xprtmultipath.c b/net/sunrpc/xprtmultipath.c
index 5df4e7adedf0..c12778e1235e 100644
--- a/net/sunrpc/xprtmultipath.c
+++ b/net/sunrpc/xprtmultipath.c
@@ -193,10 +193,22 @@  void xprt_iter_default_rewind(struct rpc_xprt_iter *xpi)
 	WRITE_ONCE(xpi->xpi_cursor, NULL);
 }
 
+static
+bool xprt_is_active(const struct rpc_xprt *xprt)
+{
+	return kref_read(&xprt->kref) != 0;
+}
+
 static
 struct rpc_xprt *xprt_switch_find_first_entry(struct list_head *head)
 {
-	return list_first_or_null_rcu(head, struct rpc_xprt, xprt_switch);
+	struct rpc_xprt *pos;
+
+	list_for_each_entry_rcu(pos, head, xprt_switch) {
+		if (xprt_is_active(pos))
+			return pos;
+	}
+	return NULL;
 }
 
 static
@@ -214,9 +226,12 @@  struct rpc_xprt *xprt_switch_find_current_entry(struct list_head *head,
 		const struct rpc_xprt *cur)
 {
 	struct rpc_xprt *pos;
+	bool found = false;
 
 	list_for_each_entry_rcu(pos, head, xprt_switch) {
 		if (cur == pos)
+			found = true;
+		if (found && xprt_is_active(pos))
 			return pos;
 	}
 	return NULL;
@@ -261,9 +276,12 @@  struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head,
 		const struct rpc_xprt *cur)
 {
 	struct rpc_xprt *pos, *prev = NULL;
+	bool found = false;
 
 	list_for_each_entry_rcu(pos, head, xprt_switch) {
 		if (cur == prev)
+			found = true;
+		if (found && xprt_is_active(pos))
 			return pos;
 		prev = pos;
 	}