RE: [PATCH] Drivers: hv: util: make struct hv_do_fcopy match Hyper-V host messages
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From: KY Srinivasan <kys@microsoft.com>
Date: 2014-10-24 15:14:30
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-----Original Message----- From: Vitaly Kuznetsov [mailto:vkuznets@redhat.com] Sent: Friday, October 24, 2014 3:20 AM To: linux-api@vger.kernel.org; KY Srinivasan Cc: Greg Kroah-Hartman; Jason Wang; linux-kernel@vger.kernel.org Subject: [PATCH] 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.
Thanks Vitaly.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <redacted>
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--- 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 index0a8e6ba..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