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author | Herbert Xu <herbert@gondor.apana.org.au> | 2014-11-07 21:22:22 +0800 |
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committer | David S. Miller <davem@davemloft.net> | 2014-11-07 12:13:34 -0500 |
commit | a8f820aa4066d2c97e75ecd1bbca8a7920b66f2c (patch) | |
tree | 69854ea942633a137e153ddd360aaa39aa2bdae6 /net/core/datagram.c | |
parent | 4e84b496fd2a226883920e0e0de4ed3f94898adf (diff) | |
download | op-kernel-dev-a8f820aa4066d2c97e75ecd1bbca8a7920b66f2c.zip op-kernel-dev-a8f820aa4066d2c97e75ecd1bbca8a7920b66f2c.tar.gz |
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: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/datagram.c')
-rw-r--r-- | net/core/datagram.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c index fdbc9a8..84d90d0 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -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> @@ -482,6 +483,92 @@ 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 * @offset: offset in the buffer to start copying to |