Merge branch 'ixp4xx' of git://git.kernel.org/pub/scm/linux/kernel/git/chris/linux...
[linux-2.6] / net / core / skb_dma_map.c
1 /* skb_dma_map.c: DMA mapping helpers for socket buffers.
2  *
3  * Copyright (C) David S. Miller <davem@davemloft.net>
4  */
5
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/dma-mapping.h>
9 #include <linux/skbuff.h>
10
11 int skb_dma_map(struct device *dev, struct sk_buff *skb,
12                 enum dma_data_direction dir)
13 {
14         struct skb_shared_info *sp = skb_shinfo(skb);
15         dma_addr_t map;
16         int i;
17
18         map = dma_map_single(dev, skb->data,
19                              skb_headlen(skb), dir);
20         if (dma_mapping_error(dev, map))
21                 goto out_err;
22
23         sp->dma_maps[0] = map;
24         for (i = 0; i < sp->nr_frags; i++) {
25                 skb_frag_t *fp = &sp->frags[i];
26
27                 map = dma_map_page(dev, fp->page, fp->page_offset,
28                                    fp->size, dir);
29                 if (dma_mapping_error(dev, map))
30                         goto unwind;
31                 sp->dma_maps[i + 1] = map;
32         }
33         sp->num_dma_maps = i + 1;
34
35         return 0;
36
37 unwind:
38         while (--i >= 0) {
39                 skb_frag_t *fp = &sp->frags[i];
40
41                 dma_unmap_page(dev, sp->dma_maps[i + 1],
42                                fp->size, dir);
43         }
44         dma_unmap_single(dev, sp->dma_maps[0],
45                          skb_headlen(skb), dir);
46 out_err:
47         return -ENOMEM;
48 }
49 EXPORT_SYMBOL(skb_dma_map);
50
51 void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
52                    enum dma_data_direction dir)
53 {
54         struct skb_shared_info *sp = skb_shinfo(skb);
55         int i;
56
57         dma_unmap_single(dev, sp->dma_maps[0],
58                          skb_headlen(skb), dir);
59         for (i = 0; i < sp->nr_frags; i++) {
60                 skb_frag_t *fp = &sp->frags[i];
61
62                 dma_unmap_page(dev, sp->dma_maps[i + 1],
63                                fp->size, dir);
64         }
65 }
66 EXPORT_SYMBOL(skb_dma_unmap);