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[3.16.y-ckt,021/216] Drivers: hv: util: make struct hv_do_fcopy match Hyper-V host messages

Message ID 1421085933-32536-22-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques Jan. 12, 2015, 6:02 p.m. UTC 
3.16.7-ckt4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vitaly Kuznetsov <vkuznets@redhat.com>

commit 31d4ea1a093fcf668d5f95af44b8d41488bdb7ec upstream.

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@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 include/uapi/linux/hyperv.h | 1 +
 1 file changed, 1 insertion(+)
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Patch

diff --git a/include/uapi/linux/hyperv.h b/include/uapi/linux/hyperv.h
index 0a8e6badb29b..bb1cb73c927a 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];