From 022cae36551ba805bf82084047945b2901d75f36 Mon Sep 17 00:00:00 2001 From: "Venkateswararao Jujjuri (JV)" Date: Fri, 28 Jan 2011 14:11:13 -0800 Subject: [PATCH] [net/9p] Preparation and helper functions for zero copy This patch prepares p9_fcall structure for zero copy. Added fields send the payload buffer information to the transport layer. In addition it adds a 'private' field for the transport layer to store mapped/pinned page information so that it can be freed/unpinned during req_done. This patch also creates trans_common.[ch] to house helper functions. It adds the following helper functions. p9_release_req_pages - Release pages after the transaction. p9_nr_pages - Return number of pages needed to accomodate the payload. payload_gup - Translates user buffer into kernel pages. Signed-off-by: Venkateswararao Jujjuri Signed-off-by: Eric Van Hensbergen --- include/net/9p/9p.h | 8 ++++ net/9p/Makefile | 1 + net/9p/protocol.c | 4 ++ net/9p/trans_common.c | 97 +++++++++++++++++++++++++++++++++++++++++++ net/9p/trans_common.h | 29 +++++++++++++ 5 files changed, 139 insertions(+) create mode 100644 net/9p/trans_common.c create mode 100644 net/9p/trans_common.h diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h index 071fd7a8d781..7aefa6d975ac 100644 --- a/include/net/9p/9p.h +++ b/include/net/9p/9p.h @@ -689,6 +689,10 @@ struct p9_rwstat { * @tag: transaction id of the request * @offset: used by marshalling routines to track currentposition in buffer * @capacity: used by marshalling routines to track total capacity + * @pubuf: Payload user buffer given by the caller + * @pubuf: Payload kernel buffer given by the caller + * @pbuf_size: pubuf/pkbuf(only one will be !NULL) size to be read/write. + * @private: For transport layer's use. * @sdata: payload * * &p9_fcall represents the structure for all 9P RPC @@ -705,6 +709,10 @@ struct p9_fcall { size_t offset; size_t capacity; + char __user *pubuf; + char *pkbuf; + size_t pbuf_size; + void *private; uint8_t *sdata; }; diff --git a/net/9p/Makefile b/net/9p/Makefile index 198a640d53a6..a0874cc1f718 100644 --- a/net/9p/Makefile +++ b/net/9p/Makefile @@ -9,6 +9,7 @@ obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o util.o \ protocol.o \ trans_fd.o \ + trans_common.o \ 9pnet_virtio-objs := \ trans_virtio.o \ diff --git a/net/9p/protocol.c b/net/9p/protocol.c index 1e308f210928..d888847db56e 100644 --- a/net/9p/protocol.c +++ b/net/9p/protocol.c @@ -606,6 +606,10 @@ void p9pdu_reset(struct p9_fcall *pdu) { pdu->offset = 0; pdu->size = 0; + pdu->private = NULL; + pdu->pubuf = NULL; + pdu->pkbuf = NULL; + pdu->pbuf_size = 0; } int p9dirent_read(char *buf, int len, struct p9_dirent *dirent, diff --git a/net/9p/trans_common.c b/net/9p/trans_common.c new file mode 100644 index 000000000000..d62b9aa58df8 --- /dev/null +++ b/net/9p/trans_common.c @@ -0,0 +1,97 @@ +/* + * Copyright IBM Corporation, 2010 + * Author Venkateswararao Jujjuri + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2.1 of the GNU Lesser General Public License + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + * + */ + +#include +#include +#include +#include +#include +#include "trans_common.h" + +/** + * p9_release_req_pages - Release pages after the transaction. + * @*private: PDU's private page of struct trans_rpage_info + */ +void +p9_release_req_pages(struct trans_rpage_info *rpinfo) +{ + int i = 0; + + while (rpinfo->rp_data[i] && rpinfo->rp_nr_pages--) { + put_page(rpinfo->rp_data[i]); + i++; + } +} +EXPORT_SYMBOL(p9_release_req_pages); + +/** + * p9_nr_pages - Return number of pages needed to accomodate the payload. + */ +int +p9_nr_pages(struct p9_req_t *req) +{ + int start_page, end_page; + start_page = (unsigned long long)req->tc->pubuf >> PAGE_SHIFT; + end_page = ((unsigned long long)req->tc->pubuf + req->tc->pbuf_size + + PAGE_SIZE - 1) >> PAGE_SHIFT; + return end_page - start_page; +} +EXPORT_SYMBOL(p9_nr_pages); + +/** + * payload_gup - Translates user buffer into kernel pages and + * pins them either for read/write through get_user_pages_fast(). + * @req: Request to be sent to server. + * @pdata_off: data offset into the first page after translation (gup). + * @pdata_len: Total length of the IO. gup may not return requested # of pages. + * @nr_pages: number of pages to accomodate the payload + * @rw: Indicates if the pages are for read or write. + */ +int +p9_payload_gup(struct p9_req_t *req, size_t *pdata_off, int *pdata_len, + int nr_pages, u8 rw) +{ + uint32_t first_page_bytes = 0; + uint32_t pdata_mapped_pages; + struct trans_rpage_info *rpinfo; + + *pdata_off = (size_t)req->tc->pubuf & (PAGE_SIZE-1); + + if (*pdata_off) + first_page_bytes = min((PAGE_SIZE - *pdata_off), + req->tc->pbuf_size); + + rpinfo = req->tc->private; + pdata_mapped_pages = get_user_pages_fast((unsigned long)req->tc->pubuf, + nr_pages, rw, &rpinfo->rp_data[0]); + + if (pdata_mapped_pages < 0) { + printk(KERN_ERR "get_user_pages_fast failed:%d udata:%p" + "nr_pages:%d\n", pdata_mapped_pages, + req->tc->pubuf, nr_pages); + pdata_mapped_pages = 0; + return -EIO; + } + rpinfo->rp_nr_pages = pdata_mapped_pages; + if (*pdata_off) { + *pdata_len = first_page_bytes; + *pdata_len += min((req->tc->pbuf_size - *pdata_len), + ((size_t)pdata_mapped_pages - 1) << PAGE_SHIFT); + } else { + *pdata_len = min(req->tc->pbuf_size, + (size_t)pdata_mapped_pages << PAGE_SHIFT); + } + return 0; +} +EXPORT_SYMBOL(p9_payload_gup); diff --git a/net/9p/trans_common.h b/net/9p/trans_common.h new file mode 100644 index 000000000000..04977e0ad938 --- /dev/null +++ b/net/9p/trans_common.h @@ -0,0 +1,29 @@ +/* + * Copyright IBM Corporation, 2010 + * Author Venkateswararao Jujjuri + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2.1 of the GNU Lesser General Public License + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + * + */ + +/** + * struct trans_rpage_info - To store mapped page information in PDU. + * @rp_alloc:Set if this structure is allocd, not a reuse unused space in pdu. + * @rp_nr_pages: Number of mapped pages + * @rp_data: Array of page pointers + */ +struct trans_rpage_info { + u8 rp_alloc; + int rp_nr_pages; + struct page *rp_data[0]; +}; + +void p9_release_req_pages(struct trans_rpage_info *); +int p9_payload_gup(struct p9_req_t *, size_t *, int *, int, u8); +int p9_nr_pages(struct p9_req_t *);