xprtrdma: Avoid Receive Queue wrapping

Commit e340c2d6ef ("xprtrdma: Reduce the doorbell rate (Receive)")
increased the number of Receive WRs that are posted by the client,
but did not increase the size of the Receive Queue allocated during
transport set-up.

This is usually not an issue because RPCRDMA_BACKWARD_WRS is defined
as (32) when SUNRPC_BACKCHANNEL is defined. In cases where it isn't,
there is a real risk of Receive Queue wrapping.

Fixes: e340c2d6ef ("xprtrdma: Reduce the doorbell rate (Receive)")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Chuck Lever 2021-04-19 14:02:03 -04:00 committed by Trond Myklebust
parent d99f2487e1
commit 32e6b68167

View file

@ -257,6 +257,7 @@ int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device)
ep->re_attr.cap.max_send_wr += 1; /* for ib_drain_sq */
ep->re_attr.cap.max_recv_wr = ep->re_max_requests;
ep->re_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
ep->re_attr.cap.max_recv_wr += RPCRDMA_MAX_RECV_BATCH;
ep->re_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
ep->re_max_rdma_segs =