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Commit a8f820aa authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

inet: Add skb_copy_datagram_iter 



This patch adds skb_copy_datagram_iter, which is identical to
skb_copy_datagram_iovec except that it operates on iov_iter
instead of iovec.

Eventually all users of skb_copy_datagram_iovec should switch
over to iov_iter and then we can remove skb_copy_datagram_iovec.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4e84b496

include/linux/skbuff.h

+3 −0
Original line number Diff line number Diff line
@@ -150,6 +150,7 @@ 
struct net_device;

struct scatterlist;

struct pipe_inode_info;

struct iov_iter;



#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)

struct nf_conntrack {
@@ -2653,6 +2654,8 @@ int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *frm, 
int skb_copy_datagram_const_iovec(const struct sk_buff *from, int offset,

				  const struct iovec *to, int to_offset,

				  int size);

int skb_copy_datagram_iter(const struct sk_buff *from, int offset,

			   struct iov_iter *to, int size);

void skb_free_datagram(struct sock *sk, struct sk_buff *skb);

void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);

int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);

net/core/datagram.c

+87 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ 
#include <linux/spinlock.h>

#include <linux/slab.h>

#include <linux/pagemap.h>

#include <linux/uio.h>



#include <net/protocol.h>

#include <linux/skbuff.h>
@@ -481,6 +482,92 @@ int skb_copy_datagram_const_iovec(const struct sk_buff *skb, int offset, 
}

EXPORT_SYMBOL(skb_copy_datagram_const_iovec);



/**

 *	skb_copy_datagram_iter - Copy a datagram to an iovec iterator.

 *	@skb: buffer to copy

 *	@offset: offset in the buffer to start copying from

 *	@to: iovec iterator to copy to

 *	@len: amount of data to copy from buffer to iovec

 */

int skb_copy_datagram_iter(const struct sk_buff *skb, int offset,

			   struct iov_iter *to, int len)

{

	int start = skb_headlen(skb);

	int i, copy = start - offset;

	struct sk_buff *frag_iter;



	trace_skb_copy_datagram_iovec(skb, len);



	/* Copy header. */

	if (copy > 0) {

		if (copy > len)

			copy = len;

		if (copy_to_iter(skb->data + offset, copy, to) != copy)

			goto short_copy;

		if ((len -= copy) == 0)

			return 0;

		offset += copy;

	}



	/* Copy paged appendix. Hmm... why does this look so complicated? */

	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {

		int end;

		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];



		WARN_ON(start > offset + len);



		end = start + skb_frag_size(frag);

		if ((copy = end - offset) > 0) {

			if (copy > len)

				copy = len;

			if (copy_page_to_iter(skb_frag_page(frag),

					      frag->page_offset + offset -

					      start, copy, to) != copy)

				goto short_copy;

			if (!(len -= copy))

				return 0;

			offset += copy;

		}

		start = end;

	}



	skb_walk_frags(skb, frag_iter) {

		int end;



		WARN_ON(start > offset + len);



		end = start + frag_iter->len;

		if ((copy = end - offset) > 0) {

			if (copy > len)

				copy = len;

			if (skb_copy_datagram_iter(frag_iter, offset - start,

						   to, copy))

				goto fault;

			if ((len -= copy) == 0)

				return 0;

			offset += copy;

		}

		start = end;

	}

	if (!len)

		return 0;



	/* This is not really a user copy fault, but rather someone

	 * gave us a bogus length on the skb.  We should probably

	 * print a warning here as it may indicate a kernel bug.

	 */



fault:

	return -EFAULT;



short_copy:

	if (iov_iter_count(to))

		goto fault;



	return 0;

}

EXPORT_SYMBOL(skb_copy_datagram_iter);



/**

 *	skb_copy_datagram_from_iovec - Copy a datagram from an iovec.

 *	@skb: buffer to copy