Drivers: hv: util: make struct hv_do_fcopy match Hyper-V host messages

An attempt to fix fcopy on i586 (bc5a5b0 Drivers: hv: util: Properly pack the data
for file copy functionality) led to a regression on x86_64 (and actually didn't fix
i586 breakage). Fcopy messages from Hyper-V host come in the following format:

struct do_fcopy_hdr | 36 bytes
0000 | 4 bytes
offset | 8 bytes
size | 4 bytes
data | 6144 bytes

On x86_64 struct hv_do_fcopy matched this format without ' __attribute__((packed))'
and on i586 adding ' __attribute__((packed))' to it doesn't change anything. Keep
the structure packed and add padding to match re reality. Tested both i586 and x86_64
on Hyper-V Server 2012 R2.

Signed-off-by: Vitaly Kuznetsov <[e-mail]>
Signed-off-by: K. Y. Srinivasan <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/uapi/linux/hyperv.h

···
 
 struct hv_do_fcopy {
 	struct hv_fcopy_hdr hdr;
+	__u32   pad;
 	__u64	offset;
 	__u32	size;
 	__u8	data[DATA_FRAGMENT];