diff options
| -rw-r--r-- | net/sunrpc/xprtrdma/backchannel.c | 104 |
1 files changed, 40 insertions, 64 deletions
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c index e1a125ad888d..ae51ef6a897a 100644 --- a/net/sunrpc/xprtrdma/backchannel.c +++ b/net/sunrpc/xprtrdma/backchannel.c @@ -19,35 +19,6 @@ #undef RPCRDMA_BACKCHANNEL_DEBUG -static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt, - unsigned int count) -{ - struct rpc_xprt *xprt = &r_xprt->rx_xprt; - struct rpcrdma_req *req; - struct rpc_rqst *rqst; - unsigned int i; - - for (i = 0; i < (count << 1); i++) { - size_t size; - - size = min_t(size_t, r_xprt->rx_data.inline_rsize, PAGE_SIZE); - req = rpcrdma_req_create(r_xprt, size, GFP_KERNEL); - if (!req) - return -ENOMEM; - rqst = &req->rl_slot; - - rqst->rq_xprt = xprt; - INIT_LIST_HEAD(&rqst->rq_bc_list); - __set_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state); - spin_lock(&xprt->bc_pa_lock); - list_add(&rqst->rq_bc_pa_list, &xprt->bc_pa_list); - spin_unlock(&xprt->bc_pa_lock); - xdr_buf_init(&rqst->rq_snd_buf, rdmab_data(req->rl_sendbuf), - size); - } - return 0; -} - /** * xprt_rdma_bc_setup - Pre-allocate resources for handling backchannel requests * @xprt: transport associated with these backchannel resources @@ -58,34 +29,10 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt, int xprt_rdma_bc_setup(struct rpc_xprt *xprt, unsigned int reqs) { struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt); - int rc; - - /* The backchannel reply path returns each rpc_rqst to the - * bc_pa_list _after_ the reply is sent. If the server is - * faster than the client, it can send another backward - * direction request before the rpc_rqst is returned to the - * list. The client rejects the request in this case. - * - * Twice as many rpc_rqsts are prepared to ensure there is - * always an rpc_rqst available as soon as a reply is sent. - */ - if (reqs > RPCRDMA_BACKWARD_WRS >> 1) - goto out_err; - - rc = rpcrdma_bc_setup_reqs(r_xprt, reqs); - if (rc) - goto out_free; - r_xprt->rx_buf.rb_bc_srv_max_requests = reqs; + r_xprt->rx_buf.rb_bc_srv_max_requests = RPCRDMA_BACKWARD_WRS >> 1; trace_xprtrdma_cb_setup(r_xprt, reqs); return 0; - -out_free: - xprt_rdma_bc_destroy(xprt, reqs); - -out_err: - pr_err("RPC: %s: setup backchannel transport failed\n", __func__); - return -ENOMEM; } /** @@ -213,6 +160,43 @@ void xprt_rdma_bc_free_rqst(struct rpc_rqst *rqst) spin_unlock(&xprt->bc_pa_lock); } +static struct rpc_rqst *rpcrdma_bc_rqst_get(struct rpcrdma_xprt *r_xprt) +{ + struct rpc_xprt *xprt = &r_xprt->rx_xprt; + struct rpcrdma_req *req; + struct rpc_rqst *rqst; + size_t size; + + spin_lock(&xprt->bc_pa_lock); + rqst = list_first_entry_or_null(&xprt->bc_pa_list, struct rpc_rqst, + rq_bc_pa_list); + if (!rqst) + goto create_req; + list_del(&rqst->rq_bc_pa_list); + spin_unlock(&xprt->bc_pa_lock); + return rqst; + +create_req: + spin_unlock(&xprt->bc_pa_lock); + + /* Set a limit to prevent a remote from overrunning our resources. + */ + if (xprt->bc_alloc_count >= RPCRDMA_BACKWARD_WRS) + return NULL; + + size = min_t(size_t, r_xprt->rx_data.inline_rsize, PAGE_SIZE); + req = rpcrdma_req_create(r_xprt, size, GFP_KERNEL); + if (!req) + return NULL; + + xprt->bc_alloc_count++; + rqst = &req->rl_slot; + rqst->rq_xprt = xprt; + __set_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state); + xdr_buf_init(&rqst->rq_snd_buf, rdmab_data(req->rl_sendbuf), size); + return rqst; +} + /** * rpcrdma_bc_receive_call - Handle a backward direction call * @r_xprt: transport receiving the call @@ -244,18 +228,10 @@ void rpcrdma_bc_receive_call(struct rpcrdma_xprt *r_xprt, pr_info("RPC: %s: %*ph\n", __func__, size, p); #endif - /* Grab a free bc rqst */ - spin_lock(&xprt->bc_pa_lock); - if (list_empty(&xprt->bc_pa_list)) { - spin_unlock(&xprt->bc_pa_lock); + rqst = rpcrdma_bc_rqst_get(r_xprt); + if (!rqst) goto out_overflow; - } - rqst = list_first_entry(&xprt->bc_pa_list, - struct rpc_rqst, rq_bc_pa_list); - list_del(&rqst->rq_bc_pa_list); - spin_unlock(&xprt->bc_pa_lock); - /* Prepare rqst */ rqst->rq_reply_bytes_recvd = 0; rqst->rq_xid = *p; |