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    Subject[PATCH 4/4] Drivers: hv: vmbus: avoid unneeded compiler optimizations in vmbus_wait_for_unload()
    Date
    Message header is modified by the hypervisor and we read it in a loop,
    we need to prevent compilers from optimizing accesses. There are no such
    optimizations at this moment, this is just a future proof.

    Suggested-by: Radim Krcmar <rkrcmar@redhat.com>
    Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    ---
    drivers/hv/channel_mgmt.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
    index 1e43967..b10e8f74 100644
    --- a/drivers/hv/channel_mgmt.c
    +++ b/drivers/hv/channel_mgmt.c
    @@ -520,7 +520,7 @@ static void vmbus_wait_for_unload(void)
    bool unloaded = false;

    while (1) {
    - if (msg->header.message_type == HVMSG_NONE) {
    + if (READ_ONCE(msg->header.message_type) == HVMSG_NONE) {
    mdelay(10);
    continue;
    }
    --
    2.5.0
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