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net: Add SKB DMA mapping helper functions.

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Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2008-09-11 04:51:14 -07:00
parent 271bff7afb
commit a40c24a133
3 changed files with 75 additions and 0 deletions
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8
include/linux/skbuff.h
View file

@ -359,6 +359,14 @@ struct sk_buff {
#include <asm/system.h>
#ifdef CONFIG_HAS_DMA
#include <linux/dma-mapping.h>
extern int skb_dma_map(struct device *dev, struct sk_buff *skb,
enum dma_data_direction dir);
extern void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
enum dma_data_direction dir);
#endif
extern void kfree_skb(struct sk_buff *skb);
extern void __kfree_skb(struct sk_buff *skb);
extern struct sk_buff *__alloc_skb(unsigned int size,

1
net/core/Makefile
View file

@ -6,6 +6,7 @@ obj-y := sock.o request_sock.o skbuff.o iovec.o datagram.o stream.o scm.o \
gen_stats.o gen_estimator.o net_namespace.o
obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
obj-$(CONFIG_HAS_DMA) += skb_dma_map.o
obj-y += dev.o ethtool.o dev_mcast.o dst.o netevent.o \
neighbour.o rtnetlink.o utils.o link_watch.o filter.o

66
net/core/skb_dma_map.c Normal file
View file

@ -0,0 +1,66 @@
/* 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);