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xen/pciback: Fine-grain the spinlocks and fix BUG: scheduling while atomic cases. 

We were using coarse spinlocks that could end up with a deadlock.
This patch fixes that and makes the spinlocks much more fine-grained.

We also drop be->watchding state spinlocks as they are already
guarded by the xenwatch_thread against multiple customers. Without
that we would trigger the BUG: scheduling while atomic.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Konrad Rzeszutek Wilk 2010-07-23 14:35:47 -04:00
parent 0513fe9e5b
commit 494ef20db6
2 changed files with 21 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/xen/xen-pciback/passthrough.c
View File

@ -113,14 +113,14 @@ int pciback_publish_pci_roots(struct pciback_device *pdev,
{
int err = 0;
struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
struct pci_dev_entry *dev_entry, *e;
struct pci_dev_entry *dev_entry, *e, *tmp;
struct pci_dev *dev;
int found;
unsigned int domain, bus;
spin_lock(&dev_data->lock);
list_for_each_entry(dev_entry, &dev_data->dev_list, list) {
list_for_each_entry_safe(dev_entry, tmp, &dev_data->dev_list, list) {
/* Only publish this device as a root if none of its
* parent bridges are exported
*/
@ -139,13 +139,16 @@ int pciback_publish_pci_roots(struct pciback_device *pdev,
bus = (unsigned int)dev_entry->dev->bus->number;
if (!found) {
spin_unlock(&dev_data->lock);
err = publish_root_cb(pdev, domain, bus);
if (err)
break;
spin_lock(&dev_data->lock);
}
}
spin_unlock(&dev_data->lock);
if (!err)
spin_unlock(&dev_data->lock);
return err;
}

26
drivers/xen/xen-pciback/xenbus.c
View File

@ -54,23 +54,29 @@ static void pciback_disconnect(struct pciback_device *pdev)
unbind_from_irqhandler(pdev->evtchn_irq, pdev);
pdev->evtchn_irq = INVALID_EVTCHN_IRQ;
}
spin_unlock(&pdev->dev_lock);
/* If the driver domain started an op, make sure we complete it
* before releasing the shared memory */
/* Note, the workqueue does not use spinlocks at all.*/
flush_workqueue(pciback_wq);
spin_lock(&pdev->dev_lock);
if (pdev->sh_info != NULL) {
xenbus_unmap_ring_vfree(pdev->xdev, pdev->sh_info);
pdev->sh_info = NULL;
}
spin_unlock(&pdev->dev_lock);
}
static void free_pdev(struct pciback_device *pdev)
{
if (pdev->be_watching)
if (pdev->be_watching) {
unregister_xenbus_watch(&pdev->be_watch);
pdev->be_watching = 0;
}
pciback_disconnect(pdev);
@ -98,7 +104,10 @@ static int pciback_do_attach(struct pciback_device *pdev, int gnt_ref,
"Error mapping other domain page in ours.");
goto out;
}
spin_lock(&pdev->dev_lock);
pdev->sh_info = vaddr;
spin_unlock(&pdev->dev_lock);
err = bind_interdomain_evtchn_to_irqhandler(
pdev->xdev->otherend_id, remote_evtchn, pciback_handle_event,
@ -108,7 +117,10 @@ static int pciback_do_attach(struct pciback_device *pdev, int gnt_ref,
"Error binding event channel to IRQ");
goto out;
}
spin_lock(&pdev->dev_lock);
pdev->evtchn_irq = err;
spin_unlock(&pdev->dev_lock);
err = 0;
dev_dbg(&pdev->xdev->dev, "Attached!\n");
@ -122,7 +134,6 @@ static int pciback_attach(struct pciback_device *pdev)
int gnt_ref, remote_evtchn;
char *magic = NULL;
spin_lock(&pdev->dev_lock);
/* Make sure we only do this setup once */
if (xenbus_read_driver_state(pdev->xdev->nodename) !=
@ -168,7 +179,6 @@ static int pciback_attach(struct pciback_device *pdev)
dev_dbg(&pdev->xdev->dev, "Connected? %d\n", err);
out:
spin_unlock(&pdev->dev_lock);
kfree(magic);
@ -340,7 +350,6 @@ static int pciback_reconfigure(struct pciback_device *pdev)
char state_str[64];
char dev_str[64];
spin_lock(&pdev->dev_lock);
dev_dbg(&pdev->xdev->dev, "Reconfiguring device ...\n");
@ -481,8 +490,6 @@ static int pciback_reconfigure(struct pciback_device *pdev)
}
out:
spin_unlock(&pdev->dev_lock);
return 0;
}
@ -539,8 +546,6 @@ static int pciback_setup_backend(struct pciback_device *pdev)
char dev_str[64];
char state_str[64];
spin_lock(&pdev->dev_lock);
/* It's possible we could get the call to setup twice, so make sure
* we're not already connected.
*/
@ -621,8 +626,6 @@ static int pciback_setup_backend(struct pciback_device *pdev)
"Error switching to initialised state!");
out:
spin_unlock(&pdev->dev_lock);
if (!err)
/* see if pcifront is already configured (if not, we'll wait) */
pciback_attach(pdev);
@ -669,6 +672,7 @@ static int pciback_xenbus_probe(struct xenbus_device *dev,
pciback_be_watch);
if (err)
goto out;
pdev->be_watching = 1;
/* We need to force a call to our callback here in case