| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 082/105] Drivers: hv: fcopy: restore correct transfer length | Date | Tue, 10 Oct 2017 21:50:53 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Olaf Hering <olaf@aepfle.de>
commit 549e658a0919e355a2b2144dc380b3729bef7f3e upstream.
Till recently the expected length of bytes read by the daemon did depend on the context. It was either hv_start_fcopy or hv_do_fcopy. The daemon had a buffer size of two pages, which was much larger than needed.
Now the expected length of bytes read by the daemon changed slightly. For START_FILE_COPY it is still the size of hv_start_fcopy. But for WRITE_TO_FILE and the other operations it is as large as the buffer that arrived via vmbus. In case of WRITE_TO_FILE that is slightly larger than a struct hv_do_fcopy. Since the buffer in the daemon was still larger everything was fine.
Currently, the daemon reads only what is actually needed. The new buffer layout is as large as a struct hv_do_fcopy, for the WRITE_TO_FILE operation. Since the kernel expects a slightly larger size, hvt_op_read will return -EINVAL because the daemon will read slightly less than expected. Address this by restoring the expected buffer size in case of WRITE_TO_FILE.
Fixes: 'c7e490fc23eb ("Drivers: hv: fcopy: convert to hv_utils_transport")' Fixes: '3f2baa8a7d2e ("Tools: hv: update buffer handling in hv_fcopy_daemon")'
Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/hv/hv_fcopy.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/hv/hv_fcopy.c +++ b/drivers/hv/hv_fcopy.c @@ -161,6 +161,10 @@ static void fcopy_send_data(struct work_ out_src = smsg_out; break; + case WRITE_TO_FILE: + out_src = fcopy_transaction.fcopy_msg; + out_len = sizeof(struct hv_do_fcopy); + break; default: out_src = fcopy_transaction.fcopy_msg; out_len = fcopy_transaction.recv_len;
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