1 /* 2 * Copyright IBM Corporation, 2010 3 * Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of version 2.1 of the GNU Lesser General Public License 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 * 13 */ 14 15 #include <linux/slab.h> 16 #include <linux/module.h> 17 #include <net/9p/9p.h> 18 #include <net/9p/client.h> 19 #include <linux/scatterlist.h> 20 #include "trans_common.h" 21 22 /** 23 * p9_release_req_pages - Release pages after the transaction. 24 * @*private: PDU's private page of struct trans_rpage_info 25 */ 26 void 27 p9_release_req_pages(struct trans_rpage_info *rpinfo) 28 { 29 int i = 0; 30 31 while (rpinfo->rp_data[i] && rpinfo->rp_nr_pages--) { 32 put_page(rpinfo->rp_data[i]); 33 i++; 34 } 35 } 36 EXPORT_SYMBOL(p9_release_req_pages); 37 38 /** 39 * p9_nr_pages - Return number of pages needed to accommodate the payload. 40 */ 41 int 42 p9_nr_pages(struct p9_req_t *req) 43 { 44 unsigned long start_page, end_page; 45 start_page = (unsigned long)req->tc->pubuf >> PAGE_SHIFT; 46 end_page = ((unsigned long)req->tc->pubuf + req->tc->pbuf_size + 47 PAGE_SIZE - 1) >> PAGE_SHIFT; 48 return end_page - start_page; 49 } 50 EXPORT_SYMBOL(p9_nr_pages); 51 52 /** 53 * payload_gup - Translates user buffer into kernel pages and 54 * pins them either for read/write through get_user_pages_fast(). 55 * @req: Request to be sent to server. 56 * @pdata_off: data offset into the first page after translation (gup). 57 * @pdata_len: Total length of the IO. gup may not return requested # of pages. 58 * @nr_pages: number of pages to accommodate the payload 59 * @rw: Indicates if the pages are for read or write. 60 */ 61 int 62 p9_payload_gup(struct p9_req_t *req, size_t *pdata_off, int *pdata_len, 63 int nr_pages, u8 rw) 64 { 65 uint32_t first_page_bytes = 0; 66 int32_t pdata_mapped_pages; 67 struct trans_rpage_info *rpinfo; 68 69 *pdata_off = (__force size_t)req->tc->pubuf & (PAGE_SIZE-1); 70 71 if (*pdata_off) 72 first_page_bytes = min(((size_t)PAGE_SIZE - *pdata_off), 73 req->tc->pbuf_size); 74 75 rpinfo = req->tc->private; 76 pdata_mapped_pages = get_user_pages_fast((unsigned long)req->tc->pubuf, 77 nr_pages, rw, &rpinfo->rp_data[0]); 78 if (pdata_mapped_pages <= 0) 79 return pdata_mapped_pages; 80 81 rpinfo->rp_nr_pages = pdata_mapped_pages; 82 if (*pdata_off) { 83 *pdata_len = first_page_bytes; 84 *pdata_len += min((req->tc->pbuf_size - *pdata_len), 85 ((size_t)pdata_mapped_pages - 1) << PAGE_SHIFT); 86 } else { 87 *pdata_len = min(req->tc->pbuf_size, 88 (size_t)pdata_mapped_pages << PAGE_SHIFT); 89 } 90 return 0; 91 } 92 EXPORT_SYMBOL(p9_payload_gup); 93