Return-Path: linux-nfs-owner@vger.kernel.org Received: from smtp.opengridcomputing.com ([72.48.136.20]:37561 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756752AbaIWWLX (ORCPT ); Tue, 23 Sep 2014 18:11:23 -0400 From: Steve Wise Subject: [PATCH V3] svcrdma: advertise the correct max payload To: fields@fieldses.org Cc: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Tue, 23 Sep 2014 17:11:22 -0500 Message-ID: <20140923221122.24227.91718.stgit@build.ogc.int> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Svcrdma currently advertises 1MB, which is too large. The correct value is the minimum of RPCSVC_MAXPAYLOAD and the max scatter-gather allowed in an NFSRDMA IO chunk * the host page size. This bug is usually benign because the Linux X64 NFSRDMA client correctly limits the payload size to the correct value (64*4096 = 256KB). But if the Linux client is PPC64 with a 64KB page size, then the client will indeed use a payload size that will overflow the server. Signed-off-by: Steve Wise --- net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 +- net/sunrpc/xprtrdma/xprt_rdma.h | 7 +++++++ 2 files changed, 8 insertions(+), 1 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c index 374feb4..4e61880 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -91,7 +91,7 @@ struct svc_xprt_class svc_rdma_class = { .xcl_name = "rdma", .xcl_owner = THIS_MODULE, .xcl_ops = &svc_rdma_ops, - .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP, + .xcl_max_payload = RPCSVC_MAXPAYLOAD_RDMA, .xcl_ident = XPRT_TRANSPORT_RDMA, }; diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index c419498..ac7fc9a 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -51,6 +51,7 @@ #include /* rpc_xprt */ #include /* RPC/RDMA protocol */ #include /* xprt parameters */ +#include /* RPCSVC_MAXPAYLOAD */ #define RDMA_RESOLVE_TIMEOUT (5000) /* 5 seconds */ #define RDMA_CONNECT_RETRY_MAX (2) /* retries if no listener backlog */ @@ -392,4 +393,10 @@ extern struct kmem_cache *svc_rdma_ctxt_cachep; /* Workqueue created in svc_rdma.c */ extern struct workqueue_struct *svc_rdma_wq; +#if RPCSVC_MAXPAYLOAD < (RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT) +#define RPCSVC_MAXPAYLOAD_RDMA RPCSVC_MAXPAYLOAD +#else +#define RPCSVC_MAXPAYLOAD_RDMA (RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT) +#endif + #endif /* _LINUX_SUNRPC_XPRT_RDMA_H */