Return-Path: Received: from mail-it0-f68.google.com ([209.85.214.68]:45856 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754719AbdLOB4L (ORCPT ); Thu, 14 Dec 2017 20:56:11 -0500 Subject: [PATCH v1 02/16] xprtrdma: Fix backchannel allocation of extra rpcrdma_reps From: Chuck Lever To: anna.schumaker@netapp.com Cc: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Thu, 14 Dec 2017 20:56:09 -0500 Message-ID: <20171215015609.13776.30088.stgit@manet.1015granger.net> In-Reply-To: <20171215015403.13776.46706.stgit@manet.1015granger.net> References: <20171215015403.13776.46706.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: The backchannel code uses rpcrdma_recv_buffer_put to add new reps to the free rep list. This also decrements rb_recv_count, which spoofs the receive overrun logic in rpcrdma_buffer_get_rep. Commit 9b06688bc3b9 ("xprtrdma: Fix additional uses of spin_lock_irqsave(rb_lock)") replaced the original open-coded list_add with a call to rpcrdma_recv_buffer_put(), but then a year later, commit 05c974669ece ("xprtrdma: Fix receive buffer accounting") added rep accounting to rpcrdma_recv_buffer_put. It was an oversight to let the backchannel continue to use this function. The fix this, let's combine the "add to free list" logic with rpcrdma_create_rep. Also, do not allocate RPCRDMA_MAX_BC_REQUESTS rpcrdma_reps in rpcrdma_buffer_create and then allocate additional rpcrdma_reps in rpcrdma_bc_setup_reps. Allocating the extra reps during backchannel set-up is sufficient. Fixes: 05c974669ece ("xprtrdma: Fix receive buffer accounting") Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/backchannel.c | 12 ++---------- net/sunrpc/xprtrdma/verbs.c | 32 +++++++++++++++++++------------- net/sunrpc/xprtrdma/xprt_rdma.h | 2 +- 3 files changed, 22 insertions(+), 24 deletions(-) diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c index 8b818bb..256c67b 100644 --- a/net/sunrpc/xprtrdma/backchannel.c +++ b/net/sunrpc/xprtrdma/backchannel.c @@ -74,21 +74,13 @@ static int rpcrdma_bc_setup_rqst(struct rpcrdma_xprt *r_xprt, static int rpcrdma_bc_setup_reps(struct rpcrdma_xprt *r_xprt, unsigned int count) { - struct rpcrdma_rep *rep; int rc = 0; while (count--) { - rep = rpcrdma_create_rep(r_xprt); - if (IS_ERR(rep)) { - pr_err("RPC: %s: reply buffer alloc failed\n", - __func__); - rc = PTR_ERR(rep); + rc = rpcrdma_create_rep(r_xprt); + if (rc) break; - } - - rpcrdma_recv_buffer_put(rep); } - return rc; } diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 8607c02..6eecd97 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1093,10 +1093,17 @@ struct rpcrdma_req * return req; } -struct rpcrdma_rep * +/** + * rpcrdma_create_rep - Allocate an rpcrdma_rep object + * @r_xprt: controlling transport + * + * Returns 0 on success or a negative errno on failure. + */ +int rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data; + struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_rep *rep; int rc; @@ -1121,12 +1128,18 @@ struct rpcrdma_rep * rep->rr_recv_wr.wr_cqe = &rep->rr_cqe; rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov; rep->rr_recv_wr.num_sge = 1; - return rep; + + spin_lock(&buf->rb_lock); + list_add(&rep->rr_list, &buf->rb_recv_bufs); + spin_unlock(&buf->rb_lock); + return 0; out_free: kfree(rep); out: - return ERR_PTR(rc); + dprintk("RPC: %s: reply buffer %d alloc failed\n", + __func__, rc); + return rc; } int @@ -1167,17 +1180,10 @@ struct rpcrdma_rep * } INIT_LIST_HEAD(&buf->rb_recv_bufs); - for (i = 0; i < buf->rb_max_requests + RPCRDMA_MAX_BC_REQUESTS; i++) { - struct rpcrdma_rep *rep; - - rep = rpcrdma_create_rep(r_xprt); - if (IS_ERR(rep)) { - dprintk("RPC: %s: reply buffer %d alloc failed\n", - __func__, i); - rc = PTR_ERR(rep); + for (i = 0; i <= buf->rb_max_requests; i++) { + rc = rpcrdma_create_rep(r_xprt); + if (rc) goto out; - } - list_add(&rep->rr_list, &buf->rb_recv_bufs); } rc = rpcrdma_sendctxs_create(r_xprt); diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 1342f743..3b63e61 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -564,8 +564,8 @@ int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *, * Buffer calls - xprtrdma/verbs.c */ struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *); -struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *); void rpcrdma_destroy_req(struct rpcrdma_req *); +int rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt); int rpcrdma_buffer_create(struct rpcrdma_xprt *); void rpcrdma_buffer_destroy(struct rpcrdma_buffer *); struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf);