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

From: Vitaly Kuznetsov
Date: Fri Oct 24 2014 - 06:20:41 EST


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 <vkuznets@xxxxxxxxxx>
---
include/uapi/linux/hyperv.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/uapi/linux/hyperv.h b/include/uapi/linux/hyperv.h
index 0a8e6ba..bb1cb73 100644
--- a/include/uapi/linux/hyperv.h
+++ b/include/uapi/linux/hyperv.h
@@ -134,6 +134,7 @@ struct hv_start_fcopy {

struct hv_do_fcopy {
struct hv_fcopy_hdr hdr;
+ __u32 pad;
__u64 offset;
__u32 size;
__u8 data[DATA_FRAGMENT];
--
1.9.3

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