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Commit a40c24a1 authored by David S. Miller's avatar David S. Miller
Browse files

net: Add SKB DMA mapping helper functions. 



Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 271bff7a

include/linux/skbuff.h

+8 −0
Original line number Diff line number Diff line
@@ -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,

net/core/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

net/core/skb_dma_map.c

0 → 100644
+66 −0
Original line number Diff line number Diff line 
/* 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);