[PATCH 3/3] drm/amdgpu: wire up the can_remove() callback

[Hamza Mahfooz <hamza.mahfooz@amd.com>]

Removing an amdgpu device that still has user space references allocated
to it causes undefined behaviour. So, implement amdgpu_pci_can_remove()
and disallow devices that still have files allocated to them from being
unbound.

Cc: stable@vger.kernel.org
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index cc69005f5b46..cfa64f3c5be5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2323,6 +2323,22 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 	return ret;
 }
 
+static bool amdgpu_pci_can_remove(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+
+	mutex_lock(&dev->filelist_mutex);
+
+	if (!list_empty(&dev->filelist)) {
+		mutex_unlock(&dev->filelist_mutex);
+		return false;
+	}
+
+	mutex_unlock(&dev->filelist_mutex);
+
+	return true;
+}
+
 static void
 amdgpu_pci_remove(struct pci_dev *pdev)
 {
@@ -2929,6 +2945,7 @@ static struct pci_driver amdgpu_kms_pci_driver = {
 	.name = DRIVER_NAME,
 	.id_table = pciidlist,
 	.probe = amdgpu_pci_probe,
+	.can_remove = amdgpu_pci_can_remove,
 	.remove = amdgpu_pci_remove,
 	.shutdown = amdgpu_pci_shutdown,
 	.driver.pm = &amdgpu_pm_ops,
-- 
2.43.0