2 files changed, 23 insertions, 12 deletions

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index fc011e13213b..c9d756b7ee9e 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -37,6 +37,8 @@ module_param_named(nointxmask, nointxmask, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(nointxmask,
                   "Disable support for PCI 2.3 style INTx masking.  If this resolves problems for specific devices, report lspci -vvvxxx to linux-pci@vger.kernel.org so the device can be fixed automatically via the broken_intx_masking flag.");
 
+static DEFINE_MUTEX(driver_lock);
+
 static int vfio_pci_enable(struct vfio_pci_device *vdev)
 {
         struct pci_dev *pdev = vdev->pdev;
@@ -163,23 +165,29 @@ static void vfio_pci_release(void *device_data)
 {
         struct vfio_pci_device *vdev = device_data;
 
-        if (atomic_dec_and_test(&vdev->refcnt)) {
+        mutex_lock(&driver_lock);
+
+        if (!(--vdev->refcnt)) {
                 vfio_spapr_pci_eeh_release(vdev->pdev);
                 vfio_pci_disable(vdev);
         }
 
+        mutex_unlock(&driver_lock);
+
         module_put(THIS_MODULE);
 }
 
 static int vfio_pci_open(void *device_data)
 {
         struct vfio_pci_device *vdev = device_data;
-        int ret;
+        int ret = 0;
 
         if (!try_module_get(THIS_MODULE))
                 return -ENODEV;
 
-        if (atomic_inc_return(&vdev->refcnt) == 1) {
+        mutex_lock(&driver_lock);
+
+        if (!vdev->refcnt) {
                 ret = vfio_pci_enable(vdev);
                 if (ret)
                         goto error;
@@ -190,10 +198,11 @@ static int vfio_pci_open(void *device_data)
                         goto error;
                 }
         }
-
-        return 0;
+        vdev->refcnt++;
 error:
-        module_put(THIS_MODULE);
+        mutex_unlock(&driver_lock);
+        if (ret)
+                module_put(THIS_MODULE);
         return ret;
 }
 
@@ -849,7 +858,6 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
         vdev->irq_type = VFIO_PCI_NUM_IRQS;
         mutex_init(&vdev->igate);
         spin_lock_init(&vdev->irqlock);
-        atomic_set(&vdev->refcnt, 0);
 
         ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
         if (ret) {
@@ -864,12 +872,15 @@ static void vfio_pci_remove(struct pci_dev *pdev)
 {
         struct vfio_pci_device *vdev;
 
+        mutex_lock(&driver_lock);
+
         vdev = vfio_del_group_dev(&pdev->dev);
-        if (!vdev)
-                return;
+        if (vdev) {
+                iommu_group_put(pdev->dev.iommu_group);
+                kfree(vdev);
+        }
 
-        iommu_group_put(pdev->dev.iommu_group);
-        kfree(vdev);
+        mutex_unlock(&driver_lock);
 }
 
 static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 9c6d5d0f3b02..31e7a30196ab 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -55,7 +55,7 @@ struct vfio_pci_device {
         bool                    bardirty;
         bool                    has_vga;
         struct pci_saved_state  *pci_saved_state;
-        atomic_t                refcnt;
+        int                     refcnt;
         struct eventfd_ctx      *err_trigger;
 };