From 71641d99ce037ea226f94d5e08f2a8f71eba08f4 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 23 Jun 2017 17:18:41 -0400 Subject: [PATCH] svcrdma: Properly compute .len and .buflen for received RPC Calls When an RPC-over-RDMA request is received, the Receive buffer contains a Transport Header possibly followed by an RPC message. Even though rq_arg.head[0] (as passed to NFSD) does not contain the Transport Header header, currently rq_arg.len includes the size of the Transport Header. That violates the intent of the xdr_buf API contract. .buflen should include everything, but .len should be exactly the length of the RPC message in the buffer. The rq_arg fields are summed together at the end of svc_rdma_recvfrom to obtain the correct return value. rq_arg.len really ought to contain the correct number of bytes already, but it currently doesn't due to the above misbehavior. Let's instead ensure that .buflen includes the length of the transport header, and that .len is always equal to head.iov_len + .page_len + tail.iov_len . Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 14 ++++---------- net/sunrpc/xprtrdma/svc_rdma_rw.c | 2 +- 2 files changed, 5 insertions(+), 11 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index 5fbcb73dd68d..ad4bd62eebf1 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -143,7 +143,6 @@ static void rdma_build_arg_xdr(struct svc_rqst *rqstp, put_page(rqstp->rq_pages[sge_no]); rqstp->rq_pages[sge_no] = page; bc -= min_t(u32, bc, ctxt->sge[sge_no].length); - rqstp->rq_arg.buflen += ctxt->sge[sge_no].length; sge_no++; } rqstp->rq_respages = &rqstp->rq_pages[sge_no]; @@ -338,6 +337,7 @@ static int svc_rdma_xdr_decode_req(struct xdr_buf *rq_arg) rq_arg->head[0].iov_base = p; hdr_len = (unsigned long)p - (unsigned long)rdma_argp; rq_arg->head[0].iov_len -= hdr_len; + rq_arg->len -= hdr_len; dprintk("svcrdma: received %s request for XID 0x%08x, hdr_len=%u\n", proc, be32_to_cpup(rdma_argp), hdr_len); return hdr_len; @@ -564,18 +564,12 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) goto out_readchunk; complete: - ret = rqstp->rq_arg.head[0].iov_len - + rqstp->rq_arg.page_len - + rqstp->rq_arg.tail[0].iov_len; svc_rdma_put_context(ctxt, 0); - dprintk("svcrdma: ret=%d, rq_arg.len=%u, " - "rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len=%zd\n", - ret, rqstp->rq_arg.len, - rqstp->rq_arg.head[0].iov_base, - rqstp->rq_arg.head[0].iov_len); + dprintk("svcrdma: recvfrom: xprt=%p, rqstp=%p, rq_arg.len=%u\n", + rdma_xprt, rqstp, rqstp->rq_arg.len); rqstp->rq_prot = IPPROTO_MAX; svc_xprt_copy_addrs(rqstp, xprt); - return ret; + return rqstp->rq_arg.len; out_readchunk: ret = svc_rdma_recv_read_chunk(rdma_xprt, rqstp, ctxt, p); diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c index 77d38a4b8d99..9d7a151b4885 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c @@ -848,7 +848,7 @@ static int svc_rdma_build_pz_read_chunk(struct svc_rqst *rqstp, head->arg.len += info->ri_chunklen; head->arg.buflen += info->ri_chunklen; - if (head->arg.len <= head->sge[0].length) { + if (head->arg.buflen <= head->sge[0].length) { /* Transport header and RPC message fit entirely * in page where head iovec resides. */ -- 2.20.1