Not having an rpcrdma_rep at call_allocate time can be a problem.
It means that send_request can't post a receive buffer to catch
the RPC's reply. Possible consequences are RPC timeouts or even
transport deadlock.
Instead of allowing an RPC to proceed if an rpcrdma_rep is
not available, return NULL to force call_allocate to wait and
try again.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/verbs.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index b80e767f..8b8abd6 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1004,8 +1004,6 @@ rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw)
/*
* Get a set of request/reply buffers.
- *
- * Reply buffer (if available) is attached to send buffer upon return.
*/
struct rpcrdma_req *
rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
@@ -1024,13 +1022,13 @@ rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
out_reqbuf:
spin_unlock(&buffers->rb_lock);
- pr_warn("RPC: %s: out of request buffers\n", __func__);
+ pr_warn("rpcrdma: out of request buffers (%p)\n", buffers);
return NULL;
out_repbuf:
+ list_add(&req->rl_free, &buffers->rb_send_bufs);
spin_unlock(&buffers->rb_lock);
- pr_warn("RPC: %s: out of reply buffers\n", __func__);
- req->rl_reply = NULL;
- return req;
+ pr_warn("rpcrdma: out of reply buffers (%p)\n", buffers);
+ return NULL;
}
/*
--
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