Chris Leech | de5506e | 2006-05-23 17:50:37 -0700 | [diff] [blame^] | 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> |
| 30 | #include <linux/rtnetlink.h> /* for BUG_TRAP */ |
| 31 | #include <net/tcp.h> |
| 32 | |
| 33 | /** |
| 34 | * dma_skb_copy_datagram_iovec - Copy a datagram to an iovec. |
| 35 | * @skb - buffer to copy |
| 36 | * @offset - offset in the buffer to start copying from |
| 37 | * @iovec - io vector to copy to |
| 38 | * @len - amount of data to copy from buffer to iovec |
| 39 | * @pinned_list - locked iovec buffer data |
| 40 | * |
| 41 | * Note: the iovec is modified during the copy. |
| 42 | */ |
| 43 | int dma_skb_copy_datagram_iovec(struct dma_chan *chan, |
| 44 | struct sk_buff *skb, int offset, struct iovec *to, |
| 45 | size_t len, struct dma_pinned_list *pinned_list) |
| 46 | { |
| 47 | int start = skb_headlen(skb); |
| 48 | int i, copy = start - offset; |
| 49 | dma_cookie_t cookie = 0; |
| 50 | |
| 51 | /* Copy header. */ |
| 52 | if (copy > 0) { |
| 53 | if (copy > len) |
| 54 | copy = len; |
| 55 | cookie = dma_memcpy_to_iovec(chan, to, pinned_list, |
| 56 | skb->data + offset, copy); |
| 57 | if (cookie < 0) |
| 58 | goto fault; |
| 59 | len -= copy; |
| 60 | if (len == 0) |
| 61 | goto end; |
| 62 | offset += copy; |
| 63 | } |
| 64 | |
| 65 | /* Copy paged appendix. Hmm... why does this look so complicated? */ |
| 66 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
| 67 | int end; |
| 68 | |
| 69 | BUG_TRAP(start <= offset + len); |
| 70 | |
| 71 | end = start + skb_shinfo(skb)->frags[i].size; |
| 72 | copy = end - offset; |
| 73 | if ((copy = end - offset) > 0) { |
| 74 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
| 75 | struct page *page = frag->page; |
| 76 | |
| 77 | if (copy > len) |
| 78 | copy = len; |
| 79 | |
| 80 | cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list, page, |
| 81 | frag->page_offset + offset - start, copy); |
| 82 | if (cookie < 0) |
| 83 | goto fault; |
| 84 | len -= copy; |
| 85 | if (len == 0) |
| 86 | goto end; |
| 87 | offset += copy; |
| 88 | } |
| 89 | start = end; |
| 90 | } |
| 91 | |
| 92 | if (skb_shinfo(skb)->frag_list) { |
| 93 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
| 94 | |
| 95 | for (; list; list = list->next) { |
| 96 | int end; |
| 97 | |
| 98 | BUG_TRAP(start <= offset + len); |
| 99 | |
| 100 | end = start + list->len; |
| 101 | copy = end - offset; |
| 102 | if (copy > 0) { |
| 103 | if (copy > len) |
| 104 | copy = len; |
| 105 | cookie = dma_skb_copy_datagram_iovec(chan, list, |
| 106 | offset - start, to, copy, |
| 107 | pinned_list); |
| 108 | if (cookie < 0) |
| 109 | goto fault; |
| 110 | len -= copy; |
| 111 | if (len == 0) |
| 112 | goto end; |
| 113 | offset += copy; |
| 114 | } |
| 115 | start = end; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | end: |
| 120 | if (!len) { |
| 121 | skb->dma_cookie = cookie; |
| 122 | return cookie; |
| 123 | } |
| 124 | |
| 125 | fault: |
| 126 | return -EFAULT; |
| 127 | } |