xprtrdma: Use new CQ API for RPC-over-RDMA client send CQs

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2498e
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, xprtrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

Because each ib_cqe carries a pointer to a completion method, the
core can now post its own operations on a consumer's QP, and handle
the completions itself, without changes to the consumer.

Send completions were previously handled entirely in the completion
upcall handler (ie, deferring to a process context is unneeded).
Thus IB_POLL_SOFTIRQ is a direct replacement for the current
xprtrdma send code path.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index b3c4472..2ebc743 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -95,10 +95,6 @@ struct rpcrdma_ep {
 #define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
 #define DECR_CQCOUNT(ep) atomic_sub_return(1, &(ep)->rep_cqcount)
 
-/* Force completion handler to ignore the signal
- */
-#define RPCRDMA_IGNORE_COMPLETION	(0ULL)
-
 /* Pre-allocate extra Work Requests for handling backward receives
  * and sends. This is a fixed value because the Work Queues are
  * allocated when the forward channel is set up.
@@ -205,11 +201,11 @@ struct rpcrdma_frmr {
 	struct scatterlist		*sg;
 	int				sg_nents;
 	struct ib_mr			*fr_mr;
+	struct ib_cqe			fr_cqe;
 	enum rpcrdma_frmr_state		fr_state;
+	struct completion		fr_linv_done;
 	struct work_struct		fr_work;
 	struct rpcrdma_xprt		*fr_xprt;
-	bool				fr_waiter;
-	struct completion		fr_linv_done;;
 	union {
 		struct ib_reg_wr	fr_regwr;
 		struct ib_send_wr	fr_invwr;
@@ -226,7 +222,6 @@ struct rpcrdma_mw {
 		struct rpcrdma_fmr	fmr;
 		struct rpcrdma_frmr	frmr;
 	};
-	void			(*mw_sendcompletion)(struct ib_wc *);
 	struct list_head	mw_list;
 	struct list_head	mw_all;
 };
@@ -282,6 +277,7 @@ struct rpcrdma_req {
 	struct rpcrdma_regbuf	*rl_sendbuf;
 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
 
+	struct ib_cqe		rl_cqe;
 	struct list_head	rl_all;
 	bool			rl_backchannel;
 };