Commit 02722a84 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'remotes/lorenzo/pci/hv' 

- Fix race when removing device (Long Li)

- Remove unused bus device removal refcount/functions (Long Li)

* remotes/lorenzo/pci/hv:
  PCI: hv: Remove bus device removal unused refcount/functions
  PCI: hv: Fix a race condition when removing the device
parents 777e5e6b 326dc2e1

drivers/pci/controller/pci-hyperv.c

+26 −38
Original line number Diff line number Diff line
@@ -444,7 +444,6 @@ enum hv_pcibus_state { 
	hv_pcibus_probed,

	hv_pcibus_installed,

	hv_pcibus_removing,

	hv_pcibus_removed,

	hv_pcibus_maximum

};
@@ -453,7 +452,6 @@ struct hv_pcibus_device { 
	/* Protocol version negotiated with the host */

	enum pci_protocol_version_t protocol_version;

	enum hv_pcibus_state state;

	refcount_t remove_lock;

	struct hv_device *hdev;

	resource_size_t low_mmio_space;

	resource_size_t high_mmio_space;
@@ -461,7 +459,6 @@ struct hv_pcibus_device { 
	struct resource *low_mmio_res;

	struct resource *high_mmio_res;

	struct completion *survey_event;

	struct completion remove_event;

	struct pci_bus *pci_bus;

	spinlock_t config_lock;	/* Avoid two threads writing index page */

	spinlock_t device_list_lock;	/* Protect lists below */
@@ -593,9 +590,6 @@ static void put_pcichild(struct hv_pci_dev *hpdev) 
		kfree(hpdev);

}



static void get_hvpcibus(struct hv_pcibus_device *hv_pcibus);

static void put_hvpcibus(struct hv_pcibus_device *hv_pcibus);



/*

 * There is no good way to get notified from vmbus_onoffer_rescind(),

 * so let's use polling here, since this is not a hot path.
@@ -2064,10 +2058,8 @@ static void pci_devices_present_work(struct work_struct *work) 
	}

	spin_unlock_irqrestore(&hbus->device_list_lock, flags);



	if (!dr) {

		put_hvpcibus(hbus);

	if (!dr)

		return;

	}



	/* First, mark all existing children as reported missing. */

	spin_lock_irqsave(&hbus->device_list_lock, flags);
@@ -2150,7 +2142,6 @@ static void pci_devices_present_work(struct work_struct *work) 
		break;

	}



	put_hvpcibus(hbus);

	kfree(dr);

}
@@ -2191,12 +2182,10 @@ static int hv_pci_start_relations_work(struct hv_pcibus_device *hbus, 
	list_add_tail(&dr->list_entry, &hbus->dr_list);

	spin_unlock_irqrestore(&hbus->device_list_lock, flags);



	if (pending_dr) {

	if (pending_dr)

		kfree(dr_wrk);

	} else {

		get_hvpcibus(hbus);

	else

		queue_work(hbus->wq, &dr_wrk->wrk);

	}



	return 0;

}
@@ -2339,8 +2328,6 @@ static void hv_eject_device_work(struct work_struct *work) 
	put_pcichild(hpdev);

	put_pcichild(hpdev);

	/* hpdev has been freed. Do not use it any more. */



	put_hvpcibus(hbus);

}



/**
@@ -2364,7 +2351,6 @@ static void hv_pci_eject_device(struct hv_pci_dev *hpdev) 
	hpdev->state = hv_pcichild_ejecting;

	get_pcichild(hpdev);

	INIT_WORK(&hpdev->wrk, hv_eject_device_work);

	get_hvpcibus(hbus);

	queue_work(hbus->wq, &hpdev->wrk);

}
@@ -2964,17 +2950,6 @@ static int hv_send_resources_released(struct hv_device *hdev) 
	return 0;

}



static void get_hvpcibus(struct hv_pcibus_device *hbus)

{

	refcount_inc(&hbus->remove_lock);

}



static void put_hvpcibus(struct hv_pcibus_device *hbus)

{

	if (refcount_dec_and_test(&hbus->remove_lock))

		complete(&hbus->remove_event);

}



#define HVPCI_DOM_MAP_SIZE (64 * 1024)

static DECLARE_BITMAP(hvpci_dom_map, HVPCI_DOM_MAP_SIZE);
@@ -3094,14 +3069,12 @@ static int hv_pci_probe(struct hv_device *hdev, 
	hbus->sysdata.domain = dom;



	hbus->hdev = hdev;

	refcount_set(&hbus->remove_lock, 1);

	INIT_LIST_HEAD(&hbus->children);

	INIT_LIST_HEAD(&hbus->dr_list);

	INIT_LIST_HEAD(&hbus->resources_for_children);

	spin_lock_init(&hbus->config_lock);

	spin_lock_init(&hbus->device_list_lock);

	spin_lock_init(&hbus->retarget_msi_interrupt_lock);

	init_completion(&hbus->remove_event);

	hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0,

					   hbus->sysdata.domain);

	if (!hbus->wq) {
@@ -3243,8 +3216,9 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) 
		struct pci_packet teardown_packet;

		u8 buffer[sizeof(struct pci_message)];

	} pkt;

	struct hv_dr_state *dr;

	struct hv_pci_compl comp_pkt;

	struct hv_pci_dev *hpdev, *tmp;

	unsigned long flags;

	int ret;



	/*
@@ -3256,9 +3230,16 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) 


	if (!keep_devs) {

		/* Delete any children which might still exist. */

		dr = kzalloc(sizeof(*dr), GFP_KERNEL);

		if (dr && hv_pci_start_relations_work(hbus, dr))

			kfree(dr);

		spin_lock_irqsave(&hbus->device_list_lock, flags);

		list_for_each_entry_safe(hpdev, tmp, &hbus->children, list_entry) {

			list_del(&hpdev->list_entry);

			if (hpdev->pci_slot)

				pci_destroy_slot(hpdev->pci_slot);

			/* For the two refs got in new_pcichild_device() */

			put_pcichild(hpdev);

			put_pcichild(hpdev);

		}

		spin_unlock_irqrestore(&hbus->device_list_lock, flags);

	}



	ret = hv_send_resources_released(hdev);
@@ -3301,13 +3282,23 @@ static int hv_pci_remove(struct hv_device *hdev) 


	hbus = hv_get_drvdata(hdev);

	if (hbus->state == hv_pcibus_installed) {

		tasklet_disable(&hdev->channel->callback_event);

		hbus->state = hv_pcibus_removing;

		tasklet_enable(&hdev->channel->callback_event);

		destroy_workqueue(hbus->wq);

		hbus->wq = NULL;

		/*

		 * At this point, no work is running or can be scheduled

		 * on hbus-wq. We can't race with hv_pci_devices_present()

		 * or hv_pci_eject_device(), it's safe to proceed.

		 */



		/* Remove the bus from PCI's point of view. */

		pci_lock_rescan_remove();

		pci_stop_root_bus(hbus->pci_bus);

		hv_pci_remove_slots(hbus);

		pci_remove_root_bus(hbus->pci_bus);

		pci_unlock_rescan_remove();

		hbus->state = hv_pcibus_removed;

	}



	ret = hv_pci_bus_exit(hdev, false);
@@ -3320,9 +3311,6 @@ static int hv_pci_remove(struct hv_device *hdev) 
	hv_pci_free_bridge_windows(hbus);

	irq_domain_remove(hbus->irq_domain);

	irq_domain_free_fwnode(hbus->sysdata.fwnode);

	put_hvpcibus(hbus);

	wait_for_completion(&hbus->remove_event);

	destroy_workqueue(hbus->wq);



	hv_put_dom_num(hbus->sysdata.domain);