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authorAlex Williamson <alex.williamson@redhat.com>2014-08-07 11:12:04 -0600
committerAlex Williamson <alex.williamson@redhat.com>2014-08-07 11:12:04 -0600
commit61d792562b53c610f9fe917f2bbc22218aa39c22 (patch)
tree639616536bce3e1855e24b8c240f688b7e62f283 /drivers/vfio
parent9c22e660ce8105debb497933b9900eaeb40836d2 (diff)
downloadop-kernel-dev-61d792562b53c610f9fe917f2bbc22218aa39c22.zip
op-kernel-dev-61d792562b53c610f9fe917f2bbc22218aa39c22.tar.gz
vfio-pci: Use mutex around open, release, and remove
Serializing open/release allows us to fix a refcnt error if we fail to enable the device and lets us prevent devices from being unbound or opened, giving us an opportunity to do bus resets on release. No restriction added to serialize binding devices to vfio-pci while the mutex is held though. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/pci/vfio_pci.c33
-rw-r--r--drivers/vfio/pci/vfio_pci_private.h2
2 files changed, 23 insertions, 12 deletions
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index fc011e1..c9d756b 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 9c6d5d0..31e7a30 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;
};
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