1 /* skb_dma_map.c: DMA mapping helpers for socket buffers.
3 * Copyright (C) David S. Miller <davem@davemloft.net>
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/dma-mapping.h>
9 #include <linux/skbuff.h>
11 int skb_dma_map(struct device *dev, struct sk_buff *skb,
12 enum dma_data_direction dir)
14 struct skb_shared_info *sp = skb_shinfo(skb);
18 map = dma_map_single(dev, skb->data,
19 skb_headlen(skb), dir);
20 if (dma_mapping_error(dev, map))
23 sp->dma_maps[0] = map;
24 for (i = 0; i < sp->nr_frags; i++) {
25 skb_frag_t *fp = &sp->frags[i];
27 map = dma_map_page(dev, fp->page, fp->page_offset,
29 if (dma_mapping_error(dev, map))
31 sp->dma_maps[i + 1] = map;
33 sp->num_dma_maps = i + 1;
39 skb_frag_t *fp = &sp->frags[i];
41 dma_unmap_page(dev, sp->dma_maps[i + 1],
44 dma_unmap_single(dev, sp->dma_maps[0],
45 skb_headlen(skb), dir);
49 EXPORT_SYMBOL(skb_dma_map);
51 void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
52 enum dma_data_direction dir)
54 struct skb_shared_info *sp = skb_shinfo(skb);
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];
62 dma_unmap_page(dev, sp->dma_maps[i + 1],
66 EXPORT_SYMBOL(skb_dma_unmap);