Commit | Line | Data |
---|---|---|
de5506e1 CL |
1 | /* |
2 | * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved. | |
3 | * Portions based on net/core/datagram.c and copyrighted by their authors. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License as published by the Free | |
7 | * Software Foundation; either version 2 of the License, or (at your option) | |
8 | * any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along with | |
16 | * this program; if not, write to the Free Software Foundation, Inc., 59 | |
17 | * Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
18 | * | |
19 | * The full GNU General Public License is included in this distribution in the | |
20 | * file called COPYING. | |
21 | */ | |
22 | ||
23 | /* | |
24 | * This code allows the net stack to make use of a DMA engine for | |
25 | * skb to iovec copies. | |
26 | */ | |
27 | ||
28 | #include <linux/dmaengine.h> | |
29 | #include <linux/socket.h> | |
de5506e1 | 30 | #include <net/tcp.h> |
64d2f085 | 31 | #include <net/netdma.h> |
de5506e1 | 32 | |
95937825 CL |
33 | #define NET_DMA_DEFAULT_COPYBREAK 4096 |
34 | ||
35 | int sysctl_tcp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK; | |
16a37aca | 36 | EXPORT_SYMBOL(sysctl_tcp_dma_copybreak); |
95937825 | 37 | |
de5506e1 CL |
38 | /** |
39 | * dma_skb_copy_datagram_iovec - Copy a datagram to an iovec. | |
40 | * @skb - buffer to copy | |
41 | * @offset - offset in the buffer to start copying from | |
42 | * @iovec - io vector to copy to | |
43 | * @len - amount of data to copy from buffer to iovec | |
44 | * @pinned_list - locked iovec buffer data | |
45 | * | |
46 | * Note: the iovec is modified during the copy. | |
47 | */ | |
48 | int dma_skb_copy_datagram_iovec(struct dma_chan *chan, | |
49 | struct sk_buff *skb, int offset, struct iovec *to, | |
50 | size_t len, struct dma_pinned_list *pinned_list) | |
51 | { | |
1a028e50 DM |
52 | int start = skb_headlen(skb); |
53 | int i, copy = start - offset; | |
285e4280 | 54 | struct sk_buff *frag_iter; |
de5506e1 CL |
55 | dma_cookie_t cookie = 0; |
56 | ||
57 | /* Copy header. */ | |
58 | if (copy > 0) { | |
59 | if (copy > len) | |
60 | copy = len; | |
61 | cookie = dma_memcpy_to_iovec(chan, to, pinned_list, | |
4ec93edb | 62 | skb->data + offset, copy); |
de5506e1 CL |
63 | if (cookie < 0) |
64 | goto fault; | |
65 | len -= copy; | |
66 | if (len == 0) | |
67 | goto end; | |
68 | offset += copy; | |
69 | } | |
70 | ||
71 | /* Copy paged appendix. Hmm... why does this look so complicated? */ | |
72 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { | |
1a028e50 | 73 | int end; |
de5506e1 | 74 | |
547b792c | 75 | WARN_ON(start > offset + len); |
1a028e50 DM |
76 | |
77 | end = start + skb_shinfo(skb)->frags[i].size; | |
de5506e1 | 78 | copy = end - offset; |
7557af25 | 79 | if (copy > 0) { |
de5506e1 CL |
80 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
81 | struct page *page = frag->page; | |
82 | ||
83 | if (copy > len) | |
84 | copy = len; | |
85 | ||
1a028e50 DM |
86 | cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list, page, |
87 | frag->page_offset + offset - start, copy); | |
de5506e1 CL |
88 | if (cookie < 0) |
89 | goto fault; | |
90 | len -= copy; | |
91 | if (len == 0) | |
92 | goto end; | |
93 | offset += copy; | |
94 | } | |
1a028e50 | 95 | start = end; |
de5506e1 CL |
96 | } |
97 | ||
285e4280 DM |
98 | skb_walk_frags(skb, frag_iter) { |
99 | int end; | |
100 | ||
101 | WARN_ON(start > offset + len); | |
102 | ||
103 | end = start + frag_iter->len; | |
104 | copy = end - offset; | |
105 | if (copy > 0) { | |
106 | if (copy > len) | |
107 | copy = len; | |
108 | cookie = dma_skb_copy_datagram_iovec(chan, frag_iter, | |
109 | offset - start, | |
110 | to, copy, | |
111 | pinned_list); | |
112 | if (cookie < 0) | |
113 | goto fault; | |
114 | len -= copy; | |
115 | if (len == 0) | |
116 | goto end; | |
117 | offset += copy; | |
de5506e1 | 118 | } |
285e4280 | 119 | start = end; |
de5506e1 CL |
120 | } |
121 | ||
122 | end: | |
123 | if (!len) { | |
124 | skb->dma_cookie = cookie; | |
125 | return cookie; | |
126 | } | |
127 | ||
128 | fault: | |
4ec93edb | 129 | return -EFAULT; |
de5506e1 | 130 | } |