2016-02-12 16:42+0100, Vitaly Kuznetsov:
> wait_for_completion() may sleep, it enables interrupts and this
> is something we really want to avoid on crashes because interrupt
> handlers can cause other crashes. Switch to the recently introduced
> vmbus_wait_for_unload() doing busy wait instead.
(Too bad we fix crashers, so there is nothing to test on. :])
> Reported-by: Radim Krcmar <rkrcmar@xxxxxxxxxx>
Reviewed-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> drivers/hv/channel_mgmt.c | 4 ++--
> drivers/hv/connection.c | 2 +-
> drivers/hv/hyperv_vmbus.h | 2 +-
> drivers/hv/vmbus_drv.c | 4 ++--
> 4 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
> index 763d0c1..bd60207 100644
> --- a/drivers/hv/channel_mgmt.c
> +++ b/drivers/hv/channel_mgmt.c
> @@ -556,7 +556,7 @@ static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
> complete(&vmbus_connection.unload_event);
> }
>
> -void vmbus_initiate_unload(void)
> +void vmbus_initiate_unload(bool crash)
> {
> struct vmbus_channel_message_header hdr;
>
> @@ -573,7 +573,7 @@ void vmbus_initiate_unload(void)
> * vmbus_initiate_unload() is also called on crash and the crash can be
> * happening in an interrupt context, where scheduling is impossible.
> */
> - if (!in_interrupt())
> + if (!crash)
> wait_for_completion(&vmbus_connection.unload_event);
> else
> vmbus_wait_for_unload();
> diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
> index 3dc5a9c..fb63d30 100644
> --- a/drivers/hv/connection.c
> +++ b/drivers/hv/connection.c
> @@ -236,7 +236,7 @@ void vmbus_disconnect(void)
> /*
> * First send the unload request to the host.
> */
> - vmbus_initiate_unload();
> + vmbus_initiate_unload(false);
>
> if (vmbus_connection.work_queue) {
> drain_workqueue(vmbus_connection.work_queue);
> diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
> index 4ebc796..e6160a0 100644
> --- a/drivers/hv/hyperv_vmbus.h
> +++ b/drivers/hv/hyperv_vmbus.h
> @@ -665,7 +665,7 @@ void hv_vss_onchannelcallback(void *);
> int hv_fcopy_init(struct hv_util_service *);
> void hv_fcopy_deinit(void);
> void hv_fcopy_onchannelcallback(void *);
> -void vmbus_initiate_unload(void);
> +void vmbus_initiate_unload(bool crash);
>
> static inline void hv_poll_channel(struct vmbus_channel *channel,
> void (*cb)(void *))
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 895eeed..08f98a1 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1266,7 +1266,7 @@ static void hv_kexec_handler(void)
> int cpu;
>
> hv_synic_clockevents_cleanup();
> - vmbus_initiate_unload();
> + vmbus_initiate_unload(false);
> for_each_online_cpu(cpu)
> smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1);
> hv_cleanup();
> @@ -1274,7 +1274,7 @@ static void hv_kexec_handler(void)
>
> static void hv_crash_handler(struct pt_regs *regs)
> {
> - vmbus_initiate_unload();
> + vmbus_initiate_unload(true);
> /*
> * In crash handler we can't schedule synic cleanup for all CPUs,
> * doing the cleanup for current CPU only. This should be sufficient
> --
> 2.5.0
>
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