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Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -08001/*
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.
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080024 */
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053025void p9_release_pages(struct page **pages, int nr_pages)
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080026{
27 int i = 0;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053028 while (pages[i] && nr_pages--) {
29 put_page(pages[i]);
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080030 i++;
31 }
32}
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053033EXPORT_SYMBOL(p9_release_pages);
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080034
35/**
Lucas De Marchi25985ed2011-03-30 22:57:33 -030036 * p9_nr_pages - Return number of pages needed to accommodate the payload.
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080037 */
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053038int p9_nr_pages(char *data, int len)
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080039{
Aneesh Kumar K.V472e7f92011-03-08 16:39:47 +053040 unsigned long start_page, end_page;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053041 start_page = (unsigned long)data >> PAGE_SHIFT;
42 end_page = ((unsigned long)data + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080043 return end_page - start_page;
44}
45EXPORT_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.
Lucas De Marchi25985ed2011-03-30 22:57:33 -030053 * @nr_pages: number of pages to accommodate the payload
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080054 * @rw: Indicates if the pages are for read or write.
55 */
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053056
57int p9_payload_gup(char *data, int *nr_pages, struct page **pages, int write)
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080058{
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053059 int nr_mapped_pages;
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080060
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053061 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;
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080065
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +053066 *nr_pages = nr_mapped_pages;
Venkateswararao Jujjuri (JV)022cae32011-01-28 14:11:13 -080067 return 0;
68}
69EXPORT_SYMBOL(p9_payload_gup);