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a40c24a1 DM |
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: | |
ab396eb0 | 38 | while (--i >= 0) { |
a40c24a1 DM |
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); |