From: Chuck Lever <chuck.lever@oracle.com>
Date: Thu, 14 Dec 2017 20:57:39 -0500
Subject: xprtrdma: Don't clear RPC_BC_PA_IN_USE on pre-allocated rpc_rqst's
Patch-mainline: v4.16-rc1
Git-commit: 30b5416bf0fd3bfef55543343ad1e85d32e32de4
References: bsc#1103992 FATE#326009
No need for the overhead of atomically setting and clearing this bit
flag for every use of a pre-allocated backchannel rpc_rqst. These
are a distinct pool of rpc_rqsts that are used only for callback
operations, so it is safe to simply leave the bit set.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/sunrpc/xprtrdma/backchannel.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -119,6 +119,7 @@ int xprt_rdma_bc_setup(struct rpc_xprt *
rqst->rq_xprt = &r_xprt->rx_xprt;
INIT_LIST_HEAD(&rqst->rq_list);
INIT_LIST_HEAD(&rqst->rq_bc_list);
+ __set_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state);
if (rpcrdma_bc_setup_rqst(r_xprt, rqst))
goto out_free;
@@ -283,11 +284,6 @@ void xprt_rdma_bc_free_rqst(struct rpc_r
dprintk("RPC: %s: freeing rqst %p (req %p)\n",
__func__, rqst, rpcr_to_rdmar(rqst));
- smp_mb__before_atomic();
- WARN_ON_ONCE(!test_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state));
- clear_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state);
- smp_mb__after_atomic();
-
spin_lock_bh(&xprt->bc_pa_lock);
list_add_tail(&rqst->rq_bc_pa_list, &xprt->bc_pa_list);
spin_unlock_bh(&xprt->bc_pa_lock);
@@ -342,7 +338,6 @@ void rpcrdma_bc_receive_call(struct rpcr
rqst->rq_xid = *p;
rqst->rq_private_buf.len = size;
- set_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state);
buf = &rqst->rq_rcv_buf;
memset(buf, 0, sizeof(*buf));