From 494ef20db6ea2e2ab1c3a45a1461e6e717fdcf48 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 23 Jul 2010 14:35:47 -0400 Subject: 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 --- drivers/xen/xen-pciback/passthrough.c | 9 ++++++--- drivers/xen/xen-pciback/xenbus.c | 26 +++++++++++++++----------- 2 files changed, 21 insertions(+), 14 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/xen-pciback/passthrough.c b/drivers/xen/xen-pciback/passthrough.c index 5386bebf..6e3999b 100644 --- a/drivers/xen/xen-pciback/passthrough.c +++ b/drivers/xen/xen-pciback/passthrough.c @@ -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; } diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c index a0cf728..70030c4 100644 --- a/drivers/xen/xen-pciback/xenbus.c +++ b/drivers/xen/xen-pciback/xenbus.c @@ -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 -- cgit v1.1