[PATCH] virtio: make PCI devices take a virtio_pci module ref

[Mark McLoughlin <markmc@redhat.com>]

Nothing takes a ref on virtio_pci, so even if you have
devices in use, rmmod will attempt to unload the module.

Fix by simply making each device take a ref on the module.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
---
 drivers/virtio/virtio_pci.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index c7dc37c..147a17f 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -322,6 +322,9 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
 		return -ENODEV;
 	}
 
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
 	/* allocate our structure and fill it out */
 	vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
 	if (vp_dev == NULL)
@@ -393,6 +396,7 @@ static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
 	pci_release_regions(pci_dev);
 	pci_disable_device(pci_dev);
 	kfree(vp_dev);
+	module_put(THIS_MODULE);
 }
 
 #ifdef CONFIG_PM
-- 
1.6.0.3