diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 84eb0a6a0b54..89d214dda360 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -952,6 +952,7 @@ void vmbus_initiate_unload(bool crash) else vmbus_wait_for_unload(); } +EXPORT_SYMBOL_GPL(vmbus_initiate_unload); static void vmbus_setup_channel_state(struct vmbus_channel *channel, struct vmbus_channel_offer_channel *offer) diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 05a36854389a..eb8bdd8bb1f5 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -441,7 +441,6 @@ void hv_vss_deinit(void); int hv_vss_pre_suspend(void); int hv_vss_pre_resume(void); void hv_vss_onchannelcallback(void *context); -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 d28ff45d4cfd..c9eeb2ec365d 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -69,19 +69,29 @@ bool vmbus_is_confidential(void) } EXPORT_SYMBOL_GPL(vmbus_is_confidential); +static bool skip_vmbus_unload; + +/* + * Allow a VMBus framebuffer driver to specify that in the case of a panic, + * it will do the VMbus unload operation once it has flushed any dirty + * portions of the framebuffer to the Hyper-V host. + */ +void vmbus_set_skip_unload(bool skip) +{ + skip_vmbus_unload = skip; +} +EXPORT_SYMBOL_GPL(vmbus_set_skip_unload); + /* * The panic notifier below is responsible solely for unloading the * vmbus connection, which is necessary in a panic event. - * - * Notice an intrincate relation of this notifier with Hyper-V - * framebuffer panic notifier exists - we need vmbus connection alive - * there in order to succeed, so we need to order both with each other - * [see hvfb_on_panic()] - this is done using notifiers' priorities. */ static int hv_panic_vmbus_unload(struct notifier_block *nb, unsigned long val, void *args) { - vmbus_initiate_unload(true); + if (!skip_vmbus_unload) + vmbus_initiate_unload(true); + return NOTIFY_DONE; } static struct notifier_block hyperv_panic_vmbus_unload_block = { @@ -2897,7 +2907,8 @@ static void hv_crash_handler(struct pt_regs *regs) { int cpu; - vmbus_initiate_unload(true); + if (!skip_vmbus_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 diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 964f1be8150c..41a3d82f0722 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1336,6 +1336,9 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, bool fb_overlap_ok); void vmbus_free_mmio(resource_size_t start, resource_size_t size); +void vmbus_initiate_unload(bool crash); +void vmbus_set_skip_unload(bool skip); + /* * GUID definitions of various offer types - services offered to the guest. */