Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail.tpi.com ([70.99.223.143]:2950 "EHLO mail.tpi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751352Ab3CKRhx (ORCPT ); Mon, 11 Mar 2013 13:37:53 -0400 From: Tim Gardner To: linux-kernel@vger.kernel.org Cc: Tim Gardner , Trond Myklebust , "J. Bruce Fields" , "David S. Miller" , Tom Tucker , Haggai Eran , Or Gerlitz , Shani Michaeli , linux-nfs@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH linux-next v2] SUNRPC: rpcrdma_register_default_external: Dynamically allocate ib_phys_buf Date: Mon, 11 Mar 2013 11:37:27 -0600 Message-Id: <1363023447-22453-1-git-send-email-tim.gardner@canonical.com> In-Reply-To: <20130310202838.GL31448@fieldses.org> References: <20130310202838.GL31448@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: rpcrdma_register_default_external() is several frames into the call stack which goes deeper yet. You run the risk of stack corruption by declaring such a large automatic variable, so move the array of 'struct ib_phys_buf' objects into the requestor structure 'struct rpcrdma_req' (which is dynamically allocated) in order to silence the frame-larger-than warning. net/sunrpc/xprtrdma/verbs.c: In function 'rpcrdma_register_default_external': net/sunrpc/xprtrdma/verbs.c:1774:1: warning: the frame size of 1056 bytes is larger than 1024 bytes [-Wframe-larger-than=] gcc version 4.6.3 Cc: Trond Myklebust Cc: "J. Bruce Fields" Cc: "David S. Miller" Cc: Tom Tucker Cc: Haggai Eran Cc: Or Gerlitz Cc: Shani Michaeli Cc: linux-nfs@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Tim Gardner --- v1 - Use kmalloc() to dynamically allocate and free the array of 'struct ib_phys_buf' objects v2 - Move the array of 'struct ib_phys_buf' objects into struct rpcrdma_req and pass this request down through rpcrdma_register_external() and rpcrdma_register_default_external(). This is less overhead then using kmalloc() and requires no extra error checking as the allocation burden is shifted to the transport client. net/sunrpc/xprtrdma/rpc_rdma.c | 2 +- net/sunrpc/xprtrdma/verbs.c | 11 ++++++----- net/sunrpc/xprtrdma/xprt_rdma.h | 3 ++- 3 files changed, 9 insertions(+), 7 deletions(-) diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index e03725b..c89448b 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -203,7 +203,7 @@ rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target, do { /* bind/register the memory, then build chunk from result. */ - int n = rpcrdma_register_external(seg, nsegs, + int n = rpcrdma_register_external(req, seg, nsegs, cur_wchunk != NULL, r_xprt); if (n <= 0) goto out; diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 93726560..5b439ed 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1730,13 +1730,14 @@ rpcrdma_deregister_memwin_external(struct rpcrdma_mr_seg *seg, } static int -rpcrdma_register_default_external(struct rpcrdma_mr_seg *seg, - int *nsegs, int writing, struct rpcrdma_ia *ia) +rpcrdma_register_default_external(struct rpcrdma_req *req, + struct rpcrdma_mr_seg *seg, int *nsegs, int writing, + struct rpcrdma_ia *ia) { int mem_priv = (writing ? IB_ACCESS_REMOTE_WRITE : IB_ACCESS_REMOTE_READ); struct rpcrdma_mr_seg *seg1 = seg; - struct ib_phys_buf ipb[RPCRDMA_MAX_DATA_SEGS]; + struct ib_phys_buf *ipb = req->rl_ipb; int len, i, rc = 0; if (*nsegs > RPCRDMA_MAX_DATA_SEGS) @@ -1791,7 +1792,7 @@ rpcrdma_deregister_default_external(struct rpcrdma_mr_seg *seg, } int -rpcrdma_register_external(struct rpcrdma_mr_seg *seg, +rpcrdma_register_external(struct rpcrdma_req *req, struct rpcrdma_mr_seg *seg, int nsegs, int writing, struct rpcrdma_xprt *r_xprt) { struct rpcrdma_ia *ia = &r_xprt->rx_ia; @@ -1827,7 +1828,7 @@ rpcrdma_register_external(struct rpcrdma_mr_seg *seg, /* Default registration each time */ default: - rc = rpcrdma_register_default_external(seg, &nsegs, writing, ia); + rc = rpcrdma_register_default_external(req, seg, &nsegs, writing, ia); break; } if (rc) diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index cc1445d..b10ed34 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -192,6 +192,7 @@ struct rpcrdma_req { struct ib_sge rl_send_iov[4]; /* for active requests */ struct ib_sge rl_iov; /* for posting */ struct ib_mr *rl_handle; /* handle for mem in rl_iov */ + struct ib_phys_buf rl_ipb[RPCRDMA_MAX_DATA_SEGS]; /* temp work array */ char rl_base[MAX_RPCRDMAHDR]; /* start of actual buffer */ __u32 rl_xdr_buf[0]; /* start of returned rpc rq_buffer */ }; @@ -327,7 +328,7 @@ int rpcrdma_register_internal(struct rpcrdma_ia *, void *, int, int rpcrdma_deregister_internal(struct rpcrdma_ia *, struct ib_mr *, struct ib_sge *); -int rpcrdma_register_external(struct rpcrdma_mr_seg *, +int rpcrdma_register_external(struct rpcrdma_req *, struct rpcrdma_mr_seg *, int, int, struct rpcrdma_xprt *); int rpcrdma_deregister_external(struct rpcrdma_mr_seg *, struct rpcrdma_xprt *, void *); -- 1.7.9.5