[PATCH v3 06/13] datagram: introduce skb_copy_and_hash_datagram_iter helper

Sagi Grimberg
2018-11-22T01:56:50Z

Introduce a helper to copy datagram into an iovec iterator
but also update a predefined hash. This is useful for
consumers of skb_copy_datagram_iter to also support inflight
data digest without having to finish to copy and only then
traverse the iovec and calculate the digest hash.

Signed-off-by: Sagi Grimberg <sagi@lightbitslabs.com>
---
include/linux/skbuff.h | 3 +++
net/core/datagram.c | 20 +++++++++++++++++++-
2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0ba687454267..b0b8d5653f0d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3309,6 +3309,9 @@ static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
}
int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
struct msghdr *msg);
+int skb_copy_and_hash_datagram_iter(const struct sk_buff *skb, int offset,
+ struct iov_iter *to, int len,
+ struct ahash_request *hash);
int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
struct iov_iter *from, int len);
int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 382543302ae5..ef262282c8be 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -465,7 +465,7 @@ int __skb_datagram_iter(const struct sk_buff *skb, int offset,
if (copy > len)
copy = len;
if (__skb_datagram_iter(frag_iter, offset - start,
- to, copy, short_copy, cb, data))
+ to, copy, fault_short, cb, data))
goto fault;
if ((len -= copy) == 0)
return 0;
@@ -492,6 +492,24 @@ int __skb_datagram_iter(const struct sk_buff *skb, int offset,
return 0;
}

+/**
+ * skb_copy_and_hash_datagram_iter - Copy datagram to an iovec iterator
+ * and update a hash.
+ * @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
+ * @hash: hash request to update
+ */
+int skb_copy_and_hash_datagram_iter(const struct sk_buff *skb, int offset,
+ struct iov_iter *to, int len,
+ struct ahash_request *hash)
+{
+ return __skb_datagram_iter(skb, offset, to, len, true,
+ hash_and_copy_to_iter, hash);
+}
+EXPORT_SYMBOL(skb_copy_and_hash_datagram_iter);
+
static size_t simple_copy_to_iter(const void *addr, size_t bytes,
void *data __always_unused, struct iov_iter *i)
{
--
2.17.1