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/* skb_dma_map.c: DMA mapping helpers for socket buffers.
*
* Copyright (C) David S. Miller <davem@davemloft.net>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/skbuff.h>
int skb_dma_map(struct device *dev, struct sk_buff *skb,
enum dma_data_direction dir)
{
struct skb_shared_info *sp = skb_shinfo(skb);
dma_addr_t map;
int i;
map = dma_map_single(dev, skb->data,
skb_headlen(skb), dir);
if (dma_mapping_error(dev, map))
goto out_err;
sp->dma_maps[0] = map;
for (i = 0; i < sp->nr_frags; i++) {
skb_frag_t *fp = &sp->frags[i];
map = dma_map_page(dev, fp->page, fp->page_offset,
fp->size, dir);
if (dma_mapping_error(dev, map))
goto unwind;
sp->dma_maps[i + 1] = map;
}
sp->num_dma_maps = i + 1;
return 0;
unwind:
while (i-- >= 0) {
skb_frag_t *fp = &sp->frags[i];
dma_unmap_page(dev, sp->dma_maps[i + 1],
fp->size, dir);
}
dma_unmap_single(dev, sp->dma_maps[0],
skb_headlen(skb), dir);
out_err:
return -ENOMEM;
}
EXPORT_SYMBOL(skb_dma_map);
void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
enum dma_data_direction dir)
{
struct skb_shared_info *sp = skb_shinfo(skb);
int i;
dma_unmap_single(dev, sp->dma_maps[0],
skb_headlen(skb), dir);
for (i = 0; i < sp->nr_frags; i++) {
skb_frag_t *fp = &sp->frags[i];
dma_unmap_page(dev, sp->dma_maps[i + 1],
fp->size, dir);
}
}
EXPORT_SYMBOL(skb_dma_unmap);
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