On Wed, Sep 21, 2022 at 06:39:05PM +0000, Stanislav Kinsburskii wrote:
> From: Stanislav Kinsburskiy <stanislav.kinsburskiy@xxxxxxxxx>
>
> Waiting to 5 seconds in case of missing VMBUS ACPI device is redundant as the
> device is either present already or won't be available at all.
> This patch enforces synchronous probing to make sure the bus traversal,
> happening upon driver registering will either find the device (if present) or
> not spend any additional time if device is absent.
>
> Signed-off-by: Stanislav Kinsburskiy <stanislav.kinsburskiy@xxxxxxxxx>
> CC: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
> CC: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> CC: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
> CC: Wei Liu <wei.liu@xxxxxxxxxx>
> CC: Dexuan Cui <decui@xxxxxxxxxxxxx>
> CC: linux-hyperv@xxxxxxxxxxxxxxx
> CC: linux-kernel@xxxxxxxxxxxxxxx
Looks good to me. I will wait for a few days for others to chime in.
CC Michael.
> ---
> drivers/hv/vmbus_drv.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 7b9f3fc3adf7..32d0009631a6 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -46,8 +46,6 @@ struct vmbus_dynid {
>
> static struct acpi_device *hv_acpi_dev;
>
> -static struct completion probe_event;
> -
> static int hyperv_cpuhp_online;
>
> static void *hv_panic_page;
> @@ -2468,7 +2466,6 @@ static int vmbus_acpi_add(struct acpi_device *device)
> ret_val = 0;
>
> acpi_walk_err:
> - complete(&probe_event);
> if (ret_val)
> vmbus_acpi_remove(device);
> return ret_val;
> @@ -2647,6 +2644,7 @@ static struct acpi_driver vmbus_acpi_driver = {
> .remove = vmbus_acpi_remove,
> },
> .drv.pm = &vmbus_bus_pm,
> + .drv.probe_type = PROBE_FORCE_SYNCHRONOUS,
> };
>
> static void hv_kexec_handler(void)
> @@ -2719,7 +2717,7 @@ static struct syscore_ops hv_synic_syscore_ops = {
>
> static int __init hv_acpi_init(void)
> {
> - int ret, t;
> + int ret;
>
> if (!hv_is_hyperv_initialized())
> return -ENODEV;
> @@ -2727,8 +2725,6 @@ static int __init hv_acpi_init(void)
> if (hv_root_partition)
> return 0;
>
> - init_completion(&probe_event);
> -
> /*
> * Get ACPI resources first.
> */
> @@ -2737,9 +2733,8 @@ static int __init hv_acpi_init(void)
> if (ret)
> return ret;
>
> - t = wait_for_completion_timeout(&probe_event, 5*HZ);
> - if (t == 0) {
> - ret = -ETIMEDOUT;
> + if (!hv_acpi_dev) {
> + ret = -ENODEV;
> goto cleanup;
> }
>
>
>
