Bug 29432

clang reports:

In file included from drivers/net/igbvf/ethtool.c:36:
drivers/net/igbvf/igbvf.h:129:15: error: duplicate member 'page'
        struct page *page;
                     ^
drivers/net/igbvf/igbvf.h:124:17: note: previous declaration is here
                        struct page *page;
                                     ^

Indeed the field is duplicate:
struct igbvf_buffer {
	dma_addr_t dma;
	struct sk_buff *skb;
	union {
		/* Tx */
		struct {
			unsigned long time_stamp;
			u16 length;
			u16 next_to_watch;
			u16 mapped_as_page;
		};
		/* Rx */
		struct {
			struct page *page;
			u64 page_dma;
			unsigned int page_offset;
		};
	};
	struct page *page;
};

GCC seems to prefer accessing the first 'page', so should the 2nd page be renamed to "dummy_page", since you have no way of accessing it?