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From: Herbert Xu <herbert@gondor.apana.org.au>
To: David Miller <davem@davemloft.net>,
	viro@ZenIV.linux.org.uk, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, bcrl@kvack.org,
	YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Subject: [PATCH 1/4] inet: Add skb_copy_datagram_iter
Date: Thu, 06 Nov 2014 16:28:18 +0800	[thread overview]
Message-ID: <E1XmIQU-0007m1-2e@gondolin.me.apana.org.au> (raw)
In-Reply-To: 20141106082704.GB29800@gondor.apana.org.au

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>
---

 include/linux/skbuff.h |    3 +
 net/core/datagram.c    |   82 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 39ec753..a405013 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -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 {
@@ -2655,6 +2656,8 @@ 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);
diff --git a/net/core/datagram.c b/net/core/datagram.c
index fdbc9a8..45a9d4d 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 +483,87 @@ 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))
+			goto fault;
+		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) {
+			int err;
+			u8  *vaddr;
+			struct page *page = skb_frag_page(frag);
+
+			if (copy > len)
+				copy = len;
+			vaddr = kmap(page);
+			err = copy_to_iter(vaddr + frag->page_offset +
+					   offset - start, copy, to);
+			kunmap(page);
+			if (err)
+				goto fault;
+			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;
+
+fault:
+	return -EFAULT;
+}
+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

  reply	other threads:[~2014-11-06  8:28 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-02 23:05 fs: Use non-const iov in aio_read/aio_write Herbert Xu
2014-11-03  0:16 ` Al Viro
2014-11-03  0:21   ` Al Viro
2014-11-03  0:22   ` Herbert Xu
2014-11-03  0:45     ` Al Viro
2014-11-03  5:37       ` [0/3] net: Kill skb_copy_datagram_const_iovec Herbert Xu
2014-11-03  5:44         ` [PATCH 1/3] tun: Modify const aio_read iovec per do_sock_read Herbert Xu
2014-11-03  5:44         ` [PATCH 3/3] net: Kill skb_copy_datagram_const_iovec Herbert Xu
2014-11-03  5:44         ` [PATCH 2/3] macvtap: Modify const aio_read iovec per do_sock_read Herbert Xu
2014-11-03 20:05         ` [0/3] net: Kill skb_copy_datagram_const_iovec David Miller
2014-11-04  3:38           ` Herbert Xu
2014-11-04  8:31             ` [PATCH 1/4] inet: Add skb_copy_datagram_iter Herbert Xu
2014-11-04 14:32               ` Al Viro
2014-11-04 14:35                 ` Al Viro
2014-11-04 14:44                   ` Herbert Xu
2014-11-04 14:52                     ` Al Viro
2014-11-04 14:55                       ` Herbert Xu
2014-11-04 14:42                 ` Herbert Xu
2014-11-04 15:13                   ` Al Viro
2014-11-05  2:22                     ` Herbert Xu
2014-11-05  3:27                       ` David Miller
2014-11-05  3:55                         ` Al Viro
2014-11-05  4:12                           ` Al Viro
2014-11-05 20:51                             ` David Miller
2014-11-05 20:50                           ` David Miller
2014-11-05 21:07                             ` Al Viro
2014-11-05 21:57                               ` David Miller
2014-11-06  3:25                                 ` Al Viro
2014-11-06  5:50                                   ` ipv4: Use standard iovec primitive in raw_probe_proto_opt Herbert Xu
2014-11-06  6:43                                     ` Al Viro
2014-11-06  6:46                                       ` Herbert Xu
2014-11-06  7:11                                         ` Al Viro
2014-11-06  9:55                                           ` Jon Maloy
2014-11-06 22:16                                             ` Al Viro
2014-11-28  5:14                                               ` Al Viro
2014-11-06 21:28                                         ` David Miller
2014-11-07  2:00                                           ` Herbert Xu
2014-11-07 13:25                                             ` [PATCH 0/2] ipv4: Simplify raw_probe_proto_opt and avoid reading user iov twice Herbert Xu
2014-11-07 13:27                                               ` [PATCH 1/2] ipv4: Use standard iovec primitive in raw_probe_proto_opt Herbert Xu
2014-11-07 13:27                                               ` [PATCH 2/2] ipv4: Avoid reading user iov twice after raw_probe_proto_opt Herbert Xu
2014-11-10 19:26                                               ` [PATCH 0/2] ipv4: Simplify raw_probe_proto_opt and avoid reading user iov twice David Miller
2014-11-06  9:50                                   ` [PATCH 1/4] inet: Add skb_copy_datagram_iter Jon Maloy
2014-11-07 21:48                                   ` David Miller
2014-11-07 22:11                                     ` Al Viro
2014-11-07 22:31                                       ` Al Viro
2014-11-07 22:35                                         ` Al Viro
2014-11-07 23:42                                       ` Al Viro
2014-11-08  2:21                                         ` Herbert Xu
2014-11-09 21:19                                         ` Al Viro
2014-11-10  5:20                                           ` David Miller
2014-11-10  6:58                                             ` Al Viro
2014-11-10  7:30                                               ` David Miller
2014-11-10  9:09                                                 ` Al Viro
2014-11-10 16:18                                                   ` David Miller
2014-11-10 10:14                                           ` Michael S. Tsirkin
2014-11-07 21:52                                   ` David Miller
2014-11-05 20:24               ` David Miller
2014-11-06  8:23                 ` Herbert Xu
2014-11-06 17:25                   ` David Miller
2014-11-07  1:59                     ` Herbert Xu
2014-11-07  3:13                       ` David Miller
2014-11-07 13:21                         ` [PATCH 0/4] Replace skb_copy_datagram_const_iovec with iterator version Herbert Xu
2014-11-07 13:22                           ` [PATCH 1/4] inet: Add skb_copy_datagram_iter Herbert Xu
2014-11-07 13:22                           ` [PATCH 2/4] tun: Use iovec iterators Herbert Xu
2014-11-07 13:22                           ` [PATCH 3/4] macvtap: " Herbert Xu
2014-11-07 13:22                           ` [PATCH 4/4] net: Kill skb_copy_datagram_const_iovec Herbert Xu
2014-11-06  8:27                 ` [PATCH 0/4] Replace skb_copy_datagram_const_iovec with iterator version Herbert Xu
2014-11-06  8:28                   ` Herbert Xu [this message]
2014-11-06 17:30                     ` [PATCH 1/4] inet: Add skb_copy_datagram_iter Al Viro
2014-11-07  1:58                       ` Herbert Xu
2014-11-06  8:28                   ` [PATCH 2/4] tun: Use iovec iterators Herbert Xu
2014-11-06  8:28                   ` [PATCH 3/4] macvtap: " Herbert Xu
2014-11-06 17:33                     ` Al Viro
2014-11-06  8:28                   ` [PATCH 4/4] net: Kill skb_copy_datagram_const_iovec Herbert Xu
2014-11-04  8:31             ` [PATCH 2/4] tun: Use iovec iterators Herbert Xu
2014-11-04  8:37               ` Herbert Xu
2014-11-05  2:49                 ` YOSHIFUJI Hideaki
2014-11-05  3:41                   ` Herbert Xu
2014-11-04  8:31             ` [PATCH 3/4] macvtap: " Herbert Xu
2014-11-04  8:31             ` [PATCH 4/4] net: Kill skb_copy_datagram_const_iovec Herbert Xu
2014-11-04  5:45           ` [0/3] " Al Viro
2014-11-05  1:53             ` Al Viro

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