datagram: introduce skb_copy_and_hash_datagram_iter helper

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.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sagi Grimberg <sagi@lightbitslabs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 19 insertions, 1 deletions

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 @@ short_copy:
         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)
 {