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 */
p9_release_pages(struct page ** pages,int nr_pages)25 void p9_release_pages(struct page **pages, int nr_pages)
26 {
27 int i;
28
29 for (i = 0; i < nr_pages; i++)
30 if (pages[i])
31 put_page(pages[i]);
32 }
33 EXPORT_SYMBOL(p9_release_pages);
34
35 /**
36 * p9_nr_pages - Return number of pages needed to accommodate the payload.
37 */
p9_nr_pages(char * data,int len)38 int p9_nr_pages(char *data, int len)
39 {
40 unsigned long start_page, end_page;
41 start_page = (unsigned long)data >> PAGE_SHIFT;
42 end_page = ((unsigned long)data + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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.
53 * @nr_pages: number of pages to accommodate the payload
54 * @rw: Indicates if the pages are for read or write.
55 */
56
p9_payload_gup(char * data,int * nr_pages,struct page ** pages,int write)57 int p9_payload_gup(char *data, int *nr_pages, struct page **pages, int write)
58 {
59 int nr_mapped_pages;
60
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;
65
66 *nr_pages = nr_mapped_pages;
67 return 0;
68 }
69 EXPORT_SYMBOL(p9_payload_gup);
70