Return-Path: Received: from mail-io0-f194.google.com ([209.85.223.194]:33763 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932473AbcFODRh (ORCPT ); Tue, 14 Jun 2016 23:17:37 -0400 Subject: [PATCH v2 17/24] xprtrdma: Chunk list encoders no longer share one rl_segments array From: Chuck Lever To: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Tue, 14 Jun 2016 23:17:35 -0400 Message-ID: <20160615031734.14794.83510.stgit@manet.1015granger.net> In-Reply-To: <20160615030626.14794.43805.stgit@manet.1015granger.net> References: <20160615030626.14794.43805.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Currently, all three chunk list encoders each use a portion of the one rl_segments array in rpcrdma_req. This is because the MWs for each chunk list were preserved in rl_segments so that ro_unmap could find and invalidate them after the RPC was complete. However, now that MWs are placed on a per-req linked list as they are registered, there is no longer any information in rpcrdma_mr_seg that is shared between ro_map and ro_unmap_{sync,safe}, and thus nothing in rl_segments needs to be preserved after rpcrdma_marshal_req is complete. Thus the rl_segments array can be used now just for the needs of each rpcrdma_convert_iovs call. Once each chunk list is encoded, the next chunk list encoder is free to re-use all of rl_segments. This means all three chunk lists in one RPC request can now each encode a full size data payload with no increase in the size of rl_segments. This is a key requirement for Kerberos support, since both the Call and Reply for a single RPC transaction are conveyed via Long messages (RDMA Read/Write). Both can be large. Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/rpc_rdma.c | 61 ++++++++++++++++++--------------------- net/sunrpc/xprtrdma/xprt_rdma.h | 36 ++++++++++------------- 2 files changed, 44 insertions(+), 53 deletions(-) diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index 6d34c1f..f60d229 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -196,8 +196,7 @@ rpcrdma_tail_pullup(struct xdr_buf *buf) * MR when they can. */ static int -rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg, - int n, int nsegs) +rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg, int n) { size_t page_offset; u32 remaining; @@ -206,7 +205,7 @@ rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg, base = vec->iov_base; page_offset = offset_in_page(base); remaining = vec->iov_len; - while (remaining && n < nsegs) { + while (remaining && n < RPCRDMA_MAX_SEGS) { seg[n].mr_page = NULL; seg[n].mr_offset = base; seg[n].mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining); @@ -230,23 +229,23 @@ rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg, static int rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos, - enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg, int nsegs) + enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg) { - int len, n = 0, p; - int page_base; + int len, n, p, page_base; struct page **ppages; + n = 0; if (pos == 0) { - n = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, n, nsegs); - if (n == nsegs) - return -EIO; + n = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, n); + if (n == RPCRDMA_MAX_SEGS) + goto out_overflow; } len = xdrbuf->page_len; ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT); page_base = xdrbuf->page_base & ~PAGE_MASK; p = 0; - while (len && n < nsegs) { + while (len && n < RPCRDMA_MAX_SEGS) { if (!ppages[p]) { /* alloc the pagelist for receiving buffer */ ppages[p] = alloc_page(GFP_ATOMIC); @@ -257,7 +256,7 @@ rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos, seg[n].mr_offset = (void *)(unsigned long) page_base; seg[n].mr_len = min_t(u32, PAGE_SIZE - page_base, len); if (seg[n].mr_len > PAGE_SIZE) - return -EIO; + goto out_overflow; len -= seg[n].mr_len; ++n; ++p; @@ -265,8 +264,8 @@ rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos, } /* Message overflows the seg array */ - if (len && n == nsegs) - return -EIO; + if (len && n == RPCRDMA_MAX_SEGS) + goto out_overflow; /* When encoding the read list, the tail is always sent inline */ if (type == rpcrdma_readch) @@ -277,12 +276,16 @@ rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos, * xdr pad bytes, saving the server an RDMA operation. */ if (xdrbuf->tail[0].iov_len < 4 && xprt_rdma_pad_optimize) return n; - n = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, n, nsegs); - if (n == nsegs) - return -EIO; + n = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, n); + if (n == RPCRDMA_MAX_SEGS) + goto out_overflow; } return n; + +out_overflow: + pr_err("rpcrdma: segment array overflow\n"); + return -EIO; } static inline __be32 * @@ -310,7 +313,7 @@ rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, struct rpc_rqst *rqst, __be32 *iptr, enum rpcrdma_chunktype rtype) { - struct rpcrdma_mr_seg *seg = req->rl_nextseg; + struct rpcrdma_mr_seg *seg; struct rpcrdma_mw *mw; unsigned int pos; int n, nsegs; @@ -323,8 +326,8 @@ rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt, pos = rqst->rq_snd_buf.head[0].iov_len; if (rtype == rpcrdma_areadch) pos = 0; - nsegs = rpcrdma_convert_iovs(&rqst->rq_snd_buf, pos, rtype, seg, - RPCRDMA_MAX_SEGS - req->rl_nchunks); + seg = req->rl_segments; + nsegs = rpcrdma_convert_iovs(&rqst->rq_snd_buf, pos, rtype, seg); if (nsegs < 0) return ERR_PTR(nsegs); @@ -349,11 +352,9 @@ rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt, mw->mw_handle, n < nsegs ? "more" : "last"); r_xprt->rx_stats.read_chunk_count++; - req->rl_nchunks++; seg += n; nsegs -= n; } while (nsegs); - req->rl_nextseg = seg; /* Finish Read list */ *iptr++ = xdr_zero; /* Next item not present */ @@ -377,7 +378,7 @@ rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, struct rpc_rqst *rqst, __be32 *iptr, enum rpcrdma_chunktype wtype) { - struct rpcrdma_mr_seg *seg = req->rl_nextseg; + struct rpcrdma_mr_seg *seg; struct rpcrdma_mw *mw; int n, nsegs, nchunks; __be32 *segcount; @@ -387,10 +388,10 @@ rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, return iptr; } + seg = req->rl_segments; nsegs = rpcrdma_convert_iovs(&rqst->rq_rcv_buf, rqst->rq_rcv_buf.head[0].iov_len, - wtype, seg, - RPCRDMA_MAX_SEGS - req->rl_nchunks); + wtype, seg); if (nsegs < 0) return ERR_PTR(nsegs); @@ -414,12 +415,10 @@ rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, r_xprt->rx_stats.write_chunk_count++; r_xprt->rx_stats.total_rdma_request += seg->mr_len; - req->rl_nchunks++; nchunks++; seg += n; nsegs -= n; } while (nsegs); - req->rl_nextseg = seg; /* Update count of segments in this Write chunk */ *segcount = cpu_to_be32(nchunks); @@ -446,7 +445,7 @@ rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, struct rpc_rqst *rqst, __be32 *iptr, enum rpcrdma_chunktype wtype) { - struct rpcrdma_mr_seg *seg = req->rl_nextseg; + struct rpcrdma_mr_seg *seg; struct rpcrdma_mw *mw; int n, nsegs, nchunks; __be32 *segcount; @@ -456,8 +455,8 @@ rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt, return iptr; } - nsegs = rpcrdma_convert_iovs(&rqst->rq_rcv_buf, 0, wtype, seg, - RPCRDMA_MAX_SEGS - req->rl_nchunks); + seg = req->rl_segments; + nsegs = rpcrdma_convert_iovs(&rqst->rq_rcv_buf, 0, wtype, seg); if (nsegs < 0) return ERR_PTR(nsegs); @@ -481,12 +480,10 @@ rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt, r_xprt->rx_stats.reply_chunk_count++; r_xprt->rx_stats.total_rdma_request += seg->mr_len; - req->rl_nchunks++; nchunks++; seg += n; nsegs -= n; } while (nsegs); - req->rl_nextseg = seg; /* Update count of segments in the Reply chunk */ *segcount = cpu_to_be32(nchunks); @@ -656,8 +653,6 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst) * send a Call message with a Position Zero Read chunk and a * regular Read chunk at the same time. */ - req->rl_nchunks = 0; - req->rl_nextseg = req->rl_segments; iptr = headerp->rm_body.rm_chunks; iptr = rpcrdma_encode_read_list(r_xprt, req, rqst, iptr, rtype); if (IS_ERR(iptr)) diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 025365c..c713483 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -171,23 +171,14 @@ rdmab_to_msg(struct rpcrdma_regbuf *rb) * o recv buffer (posted to provider) * o ib_sge (also donated to provider) * o status of reply (length, success or not) - * o bookkeeping state to get run by tasklet (list, etc) + * o bookkeeping state to get run by reply handler (list, etc) * - * These are allocated during initialization, per-transport instance; - * however, the tasklet execution list itself is global, as it should - * always be pretty short. + * These are allocated during initialization, per-transport instance. * * N of these are associated with a transport instance, and stored in * struct rpcrdma_buffer. N is the max number of outstanding requests. */ -#define RPCRDMA_MAX_DATA_SEGS ((1 * 1024 * 1024) / PAGE_SIZE) - -/* data segments + head/tail for Call + head/tail for Reply */ -#define RPCRDMA_MAX_SEGS (RPCRDMA_MAX_DATA_SEGS + 4) - -struct rpcrdma_buffer; - struct rpcrdma_rep { struct ib_cqe rr_cqe; unsigned int rr_len; @@ -267,13 +258,18 @@ struct rpcrdma_mw { * of iovs for send operations. The reason is that the iovs passed to * ib_post_{send,recv} must not be modified until the work request * completes. - * - * NOTES: - * o RPCRDMA_MAX_SEGS is the max number of addressible chunk elements we - * marshal. The number needed varies depending on the iov lists that - * are passed to us and the memory registration mode we are in. */ +/* Maximum number of page-sized "segments" per chunk list to be + * registered or invalidated. Must handle a Reply chunk: + */ +enum { + RPCRDMA_MAX_IOV_SEGS = 3, + RPCRDMA_MAX_DATA_SEGS = ((1 * 1024 * 1024) / PAGE_SIZE) + 1, + RPCRDMA_MAX_SEGS = RPCRDMA_MAX_DATA_SEGS + + RPCRDMA_MAX_IOV_SEGS, +}; + struct rpcrdma_mr_seg { /* chunk descriptors */ u32 mr_len; /* length of chunk or segment */ struct page *mr_page; /* owning page, if any */ @@ -282,10 +278,10 @@ struct rpcrdma_mr_seg { /* chunk descriptors */ #define RPCRDMA_MAX_IOVS (2) +struct rpcrdma_buffer; struct rpcrdma_req { struct list_head rl_free; unsigned int rl_niovs; - unsigned int rl_nchunks; unsigned int rl_connect_cookie; struct rpc_task *rl_task; struct rpcrdma_buffer *rl_buffer; @@ -293,13 +289,13 @@ struct rpcrdma_req { struct ib_sge rl_send_iov[RPCRDMA_MAX_IOVS]; struct rpcrdma_regbuf *rl_rdmabuf; struct rpcrdma_regbuf *rl_sendbuf; - struct list_head rl_registered; /* registered segments */ - struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; - struct rpcrdma_mr_seg *rl_nextseg; struct ib_cqe rl_cqe; struct list_head rl_all; bool rl_backchannel; + + struct list_head rl_registered; /* registered segments */ + struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; }; static inline struct rpcrdma_req *