1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/*
* Copyright IBM Corporation, 2010
* Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2.1 of the GNU Lesser General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <linux/scatterlist.h>
#include "trans_common.h"
/**
* p9_release_req_pages - Release pages after the transaction.
* @*private: PDU's private page of struct trans_rpage_info
*/
void
p9_release_req_pages(struct trans_rpage_info *rpinfo)
{
int i = 0;
while (rpinfo->rp_data[i] && rpinfo->rp_nr_pages--) {
put_page(rpinfo->rp_data[i]);
i++;
}
}
EXPORT_SYMBOL(p9_release_req_pages);
/**
* p9_nr_pages - Return number of pages needed to accomodate the payload.
*/
int
p9_nr_pages(struct p9_req_t *req)
{
int start_page, end_page;
start_page = (unsigned long long)req->tc->pubuf >> PAGE_SHIFT;
end_page = ((unsigned long long)req->tc->pubuf + req->tc->pbuf_size +
PAGE_SIZE - 1) >> PAGE_SHIFT;
return end_page - start_page;
}
EXPORT_SYMBOL(p9_nr_pages);
/**
* payload_gup - Translates user buffer into kernel pages and
* pins them either for read/write through get_user_pages_fast().
* @req: Request to be sent to server.
* @pdata_off: data offset into the first page after translation (gup).
* @pdata_len: Total length of the IO. gup may not return requested # of pages.
* @nr_pages: number of pages to accomodate the payload
* @rw: Indicates if the pages are for read or write.
*/
int
p9_payload_gup(struct p9_req_t *req, size_t *pdata_off, int *pdata_len,
int nr_pages, u8 rw)
{
uint32_t first_page_bytes = 0;
uint32_t pdata_mapped_pages;
struct trans_rpage_info *rpinfo;
*pdata_off = (size_t)req->tc->pubuf & (PAGE_SIZE-1);
if (*pdata_off)
first_page_bytes = min((PAGE_SIZE - *pdata_off),
req->tc->pbuf_size);
rpinfo = req->tc->private;
pdata_mapped_pages = get_user_pages_fast((unsigned long)req->tc->pubuf,
nr_pages, rw, &rpinfo->rp_data[0]);
if (pdata_mapped_pages < 0) {
printk(KERN_ERR "get_user_pages_fast failed:%d udata:%p"
"nr_pages:%d\n", pdata_mapped_pages,
req->tc->pubuf, nr_pages);
pdata_mapped_pages = 0;
return -EIO;
}
rpinfo->rp_nr_pages = pdata_mapped_pages;
if (*pdata_off) {
*pdata_len = first_page_bytes;
*pdata_len += min((req->tc->pbuf_size - *pdata_len),
((size_t)pdata_mapped_pages - 1) << PAGE_SHIFT);
} else {
*pdata_len = min(req->tc->pbuf_size,
(size_t)pdata_mapped_pages << PAGE_SHIFT);
}
return 0;
}
EXPORT_SYMBOL(p9_payload_gup);
|
