[PATCH v2 13/14] vfio/gvt: Fix open/close when multiple device FDs are open

From: Jason Gunthorpe <jgg@nvidia.com>
To: David Airlie <airlied@linux.ie>,
	Tony Krowiak <akrowiak@linux.ibm.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>, Daniel Vetter <daniel@ffwll.ch>,
	Diana Craciun <diana.craciun@oss.nxp.com>,
	dri-devel@lists.freedesktop.org,
	Eric Auger <eric.auger@redhat.com>,
	Eric Farman <farman@linux.ibm.com>,
	Harald Freudenberger <freude@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	intel-gfx@lists.freedesktop.org,
	intel-gvt-dev@lists.freedesktop.org,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Jason Herne <jjherne@linux.ibm.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	kvm@vger.kernel.org, Kirti Wankhede <kwankhede@nvidia.com>,
	linux-doc@vger.kernel.org, linux-s390@vger.kernel.org,
	Matthew Rosato <mjrosato@linux.ibm.com>,
	Peter Oberparleiter <oberpar@linux.ibm.com>,
	Halil Pasic <pasic@linux.ibm.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Vineeth Vijayan <vneethv@linux.ibm.com>,
	Zhi Wang <zhi.a.wang@intel.com>
Cc: "Raj, Ashok" <ashok.raj@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	Leon Romanovsky <leonro@nvidia.com>,
	Max Gurtovoy <mgurtovoy@nvidia.com>,
	Yishai Hadas <yishaih@nvidia.com>,
	Zhenyu Wang <zhenyuw@linux.intel.com>
Subject: [PATCH v2 13/14] vfio/gvt: Fix open/close when multiple device FDs are open
Date: Tue, 20 Jul 2021 14:42:59 -0300	[thread overview]
Message-ID: <13-v2-b6a5582525c9+ff96-vfio_reflck_jgg@nvidia.com> (raw)
In-Reply-To: <0-v2-b6a5582525c9+ff96-vfio_reflck_jgg@nvidia.com>

The user can open multiple device FDs if it likes, however the open
function calls vfio_register_notifier() on device global state. Calling
vfio_register_notifier() twice will trigger a WARN_ON from
notifier_chain_register() and the first close will wrongly delete the
notifier and more.

Since these really want the new open/close_device() semantics just change
the function over.

Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 1ac98f8aba31e6..7efa386449d104 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -885,7 +885,7 @@ static int intel_vgpu_group_notifier(struct notifier_block *nb,
 	return NOTIFY_OK;
 }
 
-static int intel_vgpu_open(struct mdev_device *mdev)
+static int intel_vgpu_open_device(struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = mdev_get_drvdata(mdev);
 	struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
@@ -1004,7 +1004,7 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 	vgpu->handle = 0;
 }
 
-static void intel_vgpu_release(struct mdev_device *mdev)
+static void intel_vgpu_close_device(struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = mdev_get_drvdata(mdev);
 
@@ -1753,8 +1753,8 @@ static struct mdev_parent_ops intel_vgpu_ops = {
 	.create			= intel_vgpu_create,
 	.remove			= intel_vgpu_remove,
 
-	.open			= intel_vgpu_open,
-	.release		= intel_vgpu_release,
+	.open_device		= intel_vgpu_open_device,
+	.close_device		= intel_vgpu_close_device,
 
 	.read			= intel_vgpu_read,
 	.write			= intel_vgpu_write,
-- 
2.32.0

