net: devmem: support single IOV with sendmsg

sendmsg() with a single iov becomes ITER_UBUF, sendmsg() with multiple
iovs becomes ITER_IOVEC. iter_iov_len does not return correct
value for UBUF, so teach to treat UBUF differently.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Mina Almasry <almasrymina@google.com>
Fixes: bd61848900bf ("net: devmem: Implement TX path")
Signed-off-by: Stanislav Fomichev <stfomichev@gmail.com>
Acked-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 49ece9e1888f6546fd963605f2310f8128b5ea7c..393d0622cc2881abbe6aacd37505b6ac2dab9f16 100644 (file)
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -99,7 +99,13 @@ static inline const struct iovec *iter_iov(const struct iov_iter *iter)
 }
 
 #define iter_iov_addr(iter)    (iter_iov(iter)->iov_base + (iter)->iov_offset)
-#define iter_iov_len(iter)     (iter_iov(iter)->iov_len - (iter)->iov_offset)
+
+static inline size_t iter_iov_len(const struct iov_iter *i)
+{
+       if (i->iter_type == ITER_UBUF)
+               return i->count;
+       return iter_iov(i)->iov_len - i->iov_offset;
+}
 
 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
 {

diff --git a/net/core/datagram.c b/net/core/datagram.c
index b352a10093041b72f21c0d41e7c89e07e03255f0..94cc4705e91da6ba6629ae469ae6507e9c6fdae9 100644 (file)
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -702,7 +702,8 @@ zerocopy_fill_skb_from_devmem(struct sk_buff *skb, struct iov_iter *from,
         * iov_addrs are interpreted as an offset in bytes into the dma-buf to
         * send from. We do not support other iter types.
         */
-       if (iov_iter_type(from) != ITER_IOVEC)
+       if (iov_iter_type(from) != ITER_IOVEC &&
+           iov_iter_type(from) != ITER_UBUF)
                return -EFAULT;
 
        while (length && iov_iter_count(from)) {