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022cae36 VJJ |
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 | /** | |
25985edc | 39 | * p9_nr_pages - Return number of pages needed to accommodate the payload. |
022cae36 VJJ |
40 | */ |
41 | int | |
42 | p9_nr_pages(struct p9_req_t *req) | |
43 | { | |
472e7f9f AK |
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 + | |
022cae36 VJJ |
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. | |
25985edc | 58 | * @nr_pages: number of pages to accommodate the payload |
022cae36 VJJ |
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 | uint32_t pdata_mapped_pages; | |
67 | struct trans_rpage_info *rpinfo; | |
68 | ||
69 | *pdata_off = (size_t)req->tc->pubuf & (PAGE_SIZE-1); | |
70 | ||
71 | if (*pdata_off) | |
472e7f9f AK |
72 | first_page_bytes = min(((size_t)PAGE_SIZE - *pdata_off), |
73 | req->tc->pbuf_size); | |
022cae36 VJJ |
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 | ||
79 | if (pdata_mapped_pages < 0) { | |
80 | printk(KERN_ERR "get_user_pages_fast failed:%d udata:%p" | |
81 | "nr_pages:%d\n", pdata_mapped_pages, | |
82 | req->tc->pubuf, nr_pages); | |
83 | pdata_mapped_pages = 0; | |
84 | return -EIO; | |
85 | } | |
86 | rpinfo->rp_nr_pages = pdata_mapped_pages; | |
87 | if (*pdata_off) { | |
88 | *pdata_len = first_page_bytes; | |
89 | *pdata_len += min((req->tc->pbuf_size - *pdata_len), | |
90 | ((size_t)pdata_mapped_pages - 1) << PAGE_SHIFT); | |
91 | } else { | |
92 | *pdata_len = min(req->tc->pbuf_size, | |
93 | (size_t)pdata_mapped_pages << PAGE_SHIFT); | |
94 | } | |
95 | return 0; | |
96 | } | |
97 | EXPORT_SYMBOL(p9_payload_gup); |