tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
11int 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
37unwind:
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);
46out_err:
47 return -ENOMEM;
48}
49EXPORT_SYMBOL(skb_dma_map);
50
51void 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}
66EXPORT_SYMBOL(skb_dma_unmap);