2019-10-18 16:00:16

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v2 3/3] SUNRPC: Destroy the back channel when we destroy the host transport

When we're destroying the host transport mechanism, we should ensure
that we do not leak memory by failing to release any back channel
slots that might still exist.

Reported-by: Neil Brown <[email protected]>
Reported-by: kbuild test robot <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
---
include/linux/sunrpc/bc_xprt.h | 5 +++++
net/sunrpc/backchannel_rqst.c | 2 +-
net/sunrpc/xprt.c | 5 +++++
3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h
index 87d27e13d885..d796058cdff2 100644
--- a/include/linux/sunrpc/bc_xprt.h
+++ b/include/linux/sunrpc/bc_xprt.h
@@ -64,6 +64,11 @@ static inline int xprt_setup_backchannel(struct rpc_xprt *xprt,
return 0;
}

+static inline void xprt_destroy_backchannel(struct rpc_xprt *xprt,
+ unsigned int max_reqs)
+{
+}
+
static inline bool svc_is_backchannel(const struct svc_rqst *rqstp)
{
return false;
diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 7eb251372f94..195b40c5dae4 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -220,7 +220,7 @@ void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs)
goto out;

spin_lock_bh(&xprt->bc_pa_lock);
- xprt->bc_alloc_max -= max_reqs;
+ xprt->bc_alloc_max -= min(max_reqs, xprt->bc_alloc_max);
list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) {
dprintk("RPC: req=%p\n", req);
list_del(&req->rq_bc_pa_list);
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 8a45b3ccc313..41df4c507193 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1942,6 +1942,11 @@ static void xprt_destroy_cb(struct work_struct *work)
rpc_destroy_wait_queue(&xprt->sending);
rpc_destroy_wait_queue(&xprt->backlog);
kfree(xprt->servername);
+ /*
+ * Destroy any existing back channel
+ */
+ xprt_destroy_backchannel(xprt, UINT_MAX);
+
/*
* Tear down transport state and free the rpc_xprt
*/
--
2.21.0