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    Subject[PATCH 5/7] Drivers: hv: vmbus: Ignore the offers when resuming from hibernation
    Date
    When the VM resumes, the host re-sends the offers. We should not add the
    offers to the global vmbus_connection.chn_list again.

    Added some debug code, in case the host screws up the exact info related to
    the offers.

    Signed-off-by: Dexuan Cui <decui@microsoft.com>
    ---
    drivers/hv/channel_mgmt.c | 28 +++++++++++++++++++++++++++-
    1 file changed, 27 insertions(+), 1 deletion(-)

    diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
    index addcef5..a9aeeab 100644
    --- a/drivers/hv/channel_mgmt.c
    +++ b/drivers/hv/channel_mgmt.c
    @@ -854,12 +854,38 @@ void vmbus_initiate_unload(bool crash)
    static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
    {
    struct vmbus_channel_offer_channel *offer;
    - struct vmbus_channel *newchannel;
    + struct vmbus_channel *oldchannel, *newchannel;
    + size_t offer_sz;

    offer = (struct vmbus_channel_offer_channel *)hdr;

    trace_vmbus_onoffer(offer);

    + mutex_lock(&vmbus_connection.channel_mutex);
    + oldchannel = relid2channel(offer->child_relid);
    + mutex_unlock(&vmbus_connection.channel_mutex);
    +
    + if (oldchannel != NULL) {
    + atomic_dec(&vmbus_connection.offer_in_progress);
    +
    + /*
    + * We're resuming from hibernation: we expect the host to send
    + * exactly the same offers that we had before the hibernation.
    + */
    + offer_sz = sizeof(*offer);
    + if (memcmp(offer, &oldchannel->offermsg, offer_sz) == 0)
    + return;
    +
    + pr_err("Mismatched offer from the host (relid=%d)!\n",
    + offer->child_relid);
    +
    + print_hex_dump_debug("Old vmbus offer: ", DUMP_PREFIX_OFFSET, 4,
    + 4, &oldchannel->offermsg, offer_sz, false);
    + print_hex_dump_debug("New vmbus offer: ", DUMP_PREFIX_OFFSET, 4,
    + 4, offer, offer_sz, false);
    + return;
    + }
    +
    /* Allocate the channel object and save this offer. */
    newchannel = alloc_channel();
    if (!newchannel) {
    --
    1.8.3.1
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