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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. | |
022cae36 | 24 | */ |
abfa034e | 25 | void p9_release_pages(struct page **pages, int nr_pages) |
022cae36 VJJ |
26 | { |
27 | int i = 0; | |
abfa034e AK |
28 | while (pages[i] && nr_pages--) { |
29 | put_page(pages[i]); | |
022cae36 VJJ |
30 | i++; |
31 | } | |
32 | } | |
abfa034e | 33 | EXPORT_SYMBOL(p9_release_pages); |
022cae36 VJJ |
34 | |
35 | /** | |
25985edc | 36 | * p9_nr_pages - Return number of pages needed to accommodate the payload. |
022cae36 | 37 | */ |
abfa034e | 38 | int p9_nr_pages(char *data, int len) |
022cae36 | 39 | { |
472e7f9f | 40 | unsigned long start_page, end_page; |
abfa034e AK |
41 | start_page = (unsigned long)data >> PAGE_SHIFT; |
42 | end_page = ((unsigned long)data + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
022cae36 VJJ |
43 | return end_page - start_page; |
44 | } | |
45 | EXPORT_SYMBOL(p9_nr_pages); | |
46 | ||
47 | /** | |
48 | * payload_gup - Translates user buffer into kernel pages and | |
49 | * pins them either for read/write through get_user_pages_fast(). | |
50 | * @req: Request to be sent to server. | |
51 | * @pdata_off: data offset into the first page after translation (gup). | |
52 | * @pdata_len: Total length of the IO. gup may not return requested # of pages. | |
25985edc | 53 | * @nr_pages: number of pages to accommodate the payload |
022cae36 VJJ |
54 | * @rw: Indicates if the pages are for read or write. |
55 | */ | |
022cae36 | 56 | |
abfa034e AK |
57 | int p9_payload_gup(char *data, int *nr_pages, struct page **pages, int write) |
58 | { | |
59 | int nr_mapped_pages; | |
022cae36 | 60 | |
abfa034e AK |
61 | nr_mapped_pages = get_user_pages_fast((unsigned long)data, |
62 | *nr_pages, write, pages); | |
63 | if (nr_mapped_pages <= 0) | |
64 | return nr_mapped_pages; | |
022cae36 | 65 | |
abfa034e | 66 | *nr_pages = nr_mapped_pages; |
022cae36 VJJ |
67 | return 0; |
68 | } | |
69 | EXPORT_SYMBOL(p9_payload_gup); |