/* * Copyright IBM Corporation, 2010 * Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com> * * 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 <linux/slab.h> #include <linux/module.h> #include <net/9p/9p.h> #include <net/9p/client.h> #include <linux/scatterlist.h> #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) { unsigned long start_page, end_page; start_page = (unsigned long)req->tc->pubuf >> PAGE_SHIFT; end_page = ((unsigned 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(((size_t)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);