Drivers: hv: vmbus: Add timeout to vmbus_wait_for_unload
vmbus_wait_for_unload() looks for a CHANNELMSG_UNLOAD_RESPONSE message
coming from Hyper-V. But if the message isn't found for some reason,
the panic path gets hung forever. Add a timeout of 10 seconds to prevent
this.
Fixes: 415719160d
("Drivers: hv: vmbus: avoid scheduling in interrupt context in vmbus_initiate_unload()")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/1600026449-23651-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
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@ -750,7 +750,7 @@ static void vmbus_wait_for_unload(void)
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void *page_addr;
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void *page_addr;
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struct hv_message *msg;
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struct hv_message *msg;
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struct vmbus_channel_message_header *hdr;
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struct vmbus_channel_message_header *hdr;
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u32 message_type;
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u32 message_type, i;
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/*
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/*
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* CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
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* CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
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@ -760,8 +760,11 @@ static void vmbus_wait_for_unload(void)
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* functional and vmbus_unload_response() will complete
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* functional and vmbus_unload_response() will complete
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* vmbus_connection.unload_event. If not, the last thing we can do is
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* vmbus_connection.unload_event. If not, the last thing we can do is
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* read message pages for all CPUs directly.
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* read message pages for all CPUs directly.
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*
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* Wait no more than 10 seconds so that the panic path can't get
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* hung forever in case the response message isn't seen.
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*/
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*/
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while (1) {
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for (i = 0; i < 1000; i++) {
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if (completion_done(&vmbus_connection.unload_event))
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if (completion_done(&vmbus_connection.unload_event))
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break;
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break;
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