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inet: Add skb_copy_datagram_iter

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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: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2014-11-07 21:22:22 +08:00 committed by David S. Miller
parent 4e84b496fd
commit a8f820aa40
2 changed files with 90 additions and 0 deletions
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3
include/linux/skbuff.h
View File

@ -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);

87
net/core/datagram.c
View File

@ -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 @@ fault:
}
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