From 5191955d6fc65e6d4efe8f4f10a6028298f57281 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 5 Nov 2020 11:19:42 -0500 Subject: [PATCH] SUNRPC: Prepare for xdr_stream-style decoding on the server-side A "permanent" struct xdr_stream is allocated in struct svc_rqst so that it is usable by all server-side decoders. A per-rqst scratch buffer is also allocated to handle decoding XDR data items that cross page boundaries. To demonstrate how it will be used, add the first call site for the new svcxdr_init_decode() API. As an additional part of the overall conversion, add symbolic constants for successful and failed XDR operations. Returning "0" is overloaded. Sometimes it means something failed, but sometimes it means success. To make it more clear when XDR decoding functions succeed or fail, introduce symbolic constants. Signed-off-by: Chuck Lever --- fs/nfsd/nfssvc.c | 2 ++ include/linux/sunrpc/svc.h | 16 ++++++++++++++++ net/sunrpc/svc.c | 5 +++++ 3 files changed, 23 insertions(+) diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index 27b1ad136150..74d5e58eadb0 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -1020,6 +1020,8 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) * (necessary in the NFSv4.0 compound case) */ rqstp->rq_cachetype = proc->pc_cachetype; + + svcxdr_init_decode(rqstp); if (!proc->pc_decode(rqstp, argv->iov_base)) goto out_decode_err; diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index c220b734fa69..34c2a69820e9 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -247,6 +247,8 @@ struct svc_rqst { size_t rq_xprt_hlen; /* xprt header len */ struct xdr_buf rq_arg; + struct xdr_stream rq_arg_stream; + struct page *rq_scratch_page; struct xdr_buf rq_res; struct page *rq_pages[RPCSVC_MAXPAGES + 1]; struct page * *rq_respages; /* points into rq_pages */ @@ -557,4 +559,18 @@ static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space) svc_reserve(rqstp, space + rqstp->rq_auth_slack); } +/** + * svcxdr_init_decode - Prepare an xdr_stream for svc Call decoding + * @rqstp: controlling server RPC transaction context + * + */ +static inline void svcxdr_init_decode(struct svc_rqst *rqstp) +{ + struct xdr_stream *xdr = &rqstp->rq_arg_stream; + struct kvec *argv = rqstp->rq_arg.head; + + xdr_init_decode(xdr, &rqstp->rq_arg, argv->iov_base, NULL); + xdr_set_scratch_page(xdr, rqstp->rq_scratch_page); +} + #endif /* SUNRPC_SVC_H */ diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index b41500645c3f..4187745887f0 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -614,6 +614,10 @@ svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node) rqstp->rq_server = serv; rqstp->rq_pool = pool; + rqstp->rq_scratch_page = alloc_pages_node(node, GFP_KERNEL, 0); + if (!rqstp->rq_scratch_page) + goto out_enomem; + rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node); if (!rqstp->rq_argp) goto out_enomem; @@ -842,6 +846,7 @@ void svc_rqst_free(struct svc_rqst *rqstp) { svc_release_buffer(rqstp); + put_page(rqstp->rq_scratch_page); kfree(rqstp->rq_resp); kfree(rqstp->rq_argp); kfree(rqstp->rq_auth_data);