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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
This commit is contained in:
Bjorn Helgaas 2021-07-06 10:56:30 -05:00
parent 777e5e6ba9 326dc2e1e5
commit 02722a8415
1 changed files with 26 additions and 38 deletions
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64
drivers/pci/controller/pci-hyperv.c
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@ -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);