On 6/3/2022 12:03 PM, Christoph Hellwig wrote:
Simplify mdev_{un}register_device by requiring the caller to pass in
a structure allocate as part of the parent device structure. This
removes the need for a list of parents and the separate mdev_parent
refcount as we can simplify rely on the reference to the parent device.
By removing this list, there is no way to know if parent device is
registered repeatedly? What will happen if same parent device is
registered twice? will it fail somewhere else?
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
.../driver-api/vfio-mediated-device.rst | 12 +-
Documentation/s390/vfio-ap.rst | 2 +-
Documentation/s390/vfio-ccw.rst | 2 +-
drivers/gpu/drm/i915/gvt/kvmgt.c | 5 +-
drivers/gpu/drm/i915/i915_drv.h | 2 +
drivers/s390/cio/cio.h | 2 +
drivers/s390/cio/vfio_ccw_ops.c | 6 +-
drivers/s390/crypto/vfio_ap_ops.c | 5 +-
drivers/s390/crypto/vfio_ap_private.h | 1 +
drivers/vfio/mdev/mdev_core.c | 116 +++---------------
drivers/vfio/mdev/mdev_private.h | 23 ----
drivers/vfio/mdev/mdev_sysfs.c | 4 +-
include/linux/mdev.h | 15 ++-
samples/vfio-mdev/mbochs.c | 5 +-
samples/vfio-mdev/mdpy.c | 5 +-
samples/vfio-mdev/mtty.c | 6 +-
16 files changed, 65 insertions(+), 146 deletions(-)
diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index eded8719180fb..3749f59c855fa 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -60,19 +60,19 @@ devices as examples, as these devices are the first devices to use this module::
| MDEV CORE |
| MODULE |
| mdev.ko |
- | +-----------+ | mdev_register_device() +--------------+
+ | +-----------+ | mdev_register_parent() +--------------+
| | | +<------------------------+ |
| | | | | nvidia.ko |<-> physical
| | | +------------------------>+ | device
| | | | callbacks +--------------+
| | Physical | |
- | | device | | mdev_register_device() +--------------+
+ | | device | | mdev_register_parent() +--------------+
| | interface | |<------------------------+ |
| | | | | i915.ko |<-> physical
| | | +------------------------>+ | device
| | | | callbacks +--------------+
| | | |
- | | | | mdev_register_device() +--------------+
+ | | | | mdev_register_parent() +--------------+
| | | +<------------------------+ |
| | | | | ccw_device.ko|<-> physical
| | | +------------------------>+ | device
@@ -127,8 +127,8 @@ vfio_device_ops.
When a driver wants to add the GUID creation sysfs to an existing device it has
probe'd to then it should call::
- extern int mdev_register_device(struct device *dev,
- struct mdev_driver *mdev_driver);
+ int mdev_register_parent(struct mdev_parent *parent, struct device *dev,
+ struct mdev_driver *mdev_driver);
No need to change API name as it still registers 'struct device *dev',
it could be 'mdev_register_device' but with new argument list.
This will provide the 'mdev_supported_types/XX/create' files which can then be
used to trigger the creation of a mdev_device. The created mdev_device will be
@@ -136,7 +136,7 @@ attached to the specified driver.
When the driver needs to remove itself it calls::
- extern void mdev_unregister_device(struct device *dev);
+ void mdev_unregister_parent(struct mdev_parent *parent);
Same as above.
Which will unbind and destroy all the created mdevs and remove the sysfs files.
diff --git a/Documentation/s390/vfio-ap.rst b/Documentation/s390/vfio-ap.rst
index f57ae621f33e8..37e16158c7fbf 100644
--- a/Documentation/s390/vfio-ap.rst
+++ b/Documentation/s390/vfio-ap.rst
@@ -299,7 +299,7 @@ of the VFIO AP mediated matrix device driver::
| MDEV CORE |
| MODULE |
| mdev.ko |
- | +---------+ | mdev_register_device() +--------------+
+ | +---------+ | mdev_register_parent() +--------------+
| |Physical | +<-----------------------+ |
| | device | | | vfio_ap.ko |<-> matrix
| |interface| +----------------------->+ | device
diff --git a/Documentation/s390/vfio-ccw.rst b/Documentation/s390/vfio-ccw.rst
index 8aad08a8b8a50..ea928a3806f43 100644
--- a/Documentation/s390/vfio-ccw.rst
+++ b/Documentation/s390/vfio-ccw.rst
@@ -156,7 +156,7 @@ Below is a high Level block diagram::
| MDEV CORE |
| MODULE |
| mdev.ko |
- | +---------+ | mdev_register_device() +--------------+
+ | +---------+ | mdev_register_parent() +--------------+
| |Physical | +<-----------------------+ |
| | device | | | vfio_ccw.ko |<-> subchannel
| |interface| +----------------------->+ | device
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index e2f6c56ab3420..37bda01c1bb97 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1960,7 +1960,7 @@ static void intel_gvt_clean_device(struct drm_i915_private *i915)
if (drm_WARN_ON(&i915->drm, !gvt))
return;
- mdev_unregister_device(i915->drm.dev);
+ mdev_unregister_parent(&i915->vgpu.parent);
Ideally, parent should be member of gvt. There could be multiple vgpus
created on one physical device. Intel folks would be better reviewer though.
intel_gvt_cleanup_vgpu_type_groups(gvt);
intel_gvt_destroy_idle_vgpu(gvt->idle_vgpu);
intel_gvt_clean_vgpu_types(gvt);
@@ -2065,7 +2065,8 @@ static int intel_gvt_init_device(struct drm_i915_private *i915)
if (ret)
goto out_destroy_idle_vgpu;
- ret = mdev_register_device(i915->drm.dev, &intel_vgpu_mdev_driver);
+ ret = mdev_register_parent(&i915->vgpu.parent, i915->drm.dev,
+ &intel_vgpu_mdev_driver);
if (ret)
goto out_cleanup_vgpu_type_groups;
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 00d7eeae33bd3..7d62cc9a57e4e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -32,6 +32,7 @@
#include <uapi/drm/i915_drm.h>
+#include <linux/mdev.h>
#include <linux/pm_qos.h>
#include <drm/drm_connector.h>
@@ -400,6 +401,7 @@ struct i915_frontbuffer_tracking {
struct i915_virtual_gpu {
struct mutex lock; /* serialises sending of g2v_notify command pkts */
+ struct mdev_parent parent;
bool active;
u32 caps;
u32 *initial_mmio;
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index 1cb9daf9c6450..4ae462da7b45b 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -5,6 +5,7 @@
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
+#include <linux/mdev.h>
#include <asm/chpid.h>
#include <asm/cio.h>
#include <asm/fcx.h>
@@ -104,6 +105,7 @@ struct subchannel {
struct schib_config config;
u64 dma_mask;
char *driver_override; /* Driver name to force a match */
+ struct mdev_parent parent;
} __attribute__ ((aligned(8)));
DECLARE_PER_CPU_ALIGNED(struct irb, cio_irb);
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index b49e2e9db2dc6..9192a21085ce4 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -11,7 +11,6 @@
*/
#include <linux/vfio.h>
-#include <linux/mdev.h>
#include <linux/nospec.h>
#include <linux/slab.h>
@@ -660,10 +659,11 @@ struct mdev_driver vfio_ccw_mdev_driver = {
int vfio_ccw_mdev_reg(struct subchannel *sch)
{
- return mdev_register_device(&sch->dev, &vfio_ccw_mdev_driver);
+ return mdev_register_parent(&sch->parent, &sch->dev,
+ &vfio_ccw_mdev_driver);
}
void vfio_ccw_mdev_unreg(struct subchannel *sch)
{
- mdev_unregister_device(&sch->dev);
+ mdev_unregister_parent(&sch->parent);
}
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index a7d2a95796d36..834945150dc9f 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1485,7 +1485,8 @@ int vfio_ap_mdev_register(void)
if (ret)
return ret;
- ret = mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_driver);
+ ret = mdev_register_parent(&matrix_dev->parent, &matrix_dev->device,
+ &vfio_ap_matrix_driver);
if (ret)
goto err_driver;
return 0;
@@ -1497,6 +1498,6 @@ int vfio_ap_mdev_register(void)
void vfio_ap_mdev_unregister(void)
{
- mdev_unregister_device(&matrix_dev->device);
+ mdev_unregister_parent(&matrix_dev->parent);
mdev_unregister_driver(&vfio_ap_matrix_driver);
}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index a26efd804d0df..b97dc548a7c95 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -46,6 +46,7 @@ struct ap_matrix_dev {
struct list_head mdev_list;
struct mutex lock;
struct ap_driver *vfio_ap_drv;
+ struct mdev_parent parent;
};
extern struct ap_matrix_dev *matrix_dev;
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index b8b9e7911e559..8b5a2b3f0c882 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -20,8 +20,6 @@
#define DRIVER_AUTHOR "NVIDIA Corporation"
#define DRIVER_DESC "Mediated device Core Driver"
-static LIST_HEAD(parent_list);
-static DEFINE_MUTEX(parent_list_lock);
static struct class_compat *mdev_bus_compat_class;
static LIST_HEAD(mdev_list);
@@ -63,28 +61,6 @@ struct device *mtype_get_parent_dev(struct mdev_type *mtype)
}
EXPORT_SYMBOL(mtype_get_parent_dev);
-/* Should be called holding parent_list_lock */
-static struct mdev_parent *__find_parent_device(struct device *dev)
-{
- struct mdev_parent *parent;
-
- list_for_each_entry(parent, &parent_list, next) {
- if (parent->dev == dev)
- return parent;
- }
- return NULL;
-}
-
-void mdev_release_parent(struct kref *kref)
-{
- struct mdev_parent *parent = container_of(kref, struct mdev_parent,
- ref);
- struct device *dev = parent->dev;
-
- kfree(parent);
- put_device(dev);
-}
-
/* Caller must hold parent unreg_sem read or write lock */
static void mdev_device_remove_common(struct mdev_device *mdev)
{
@@ -107,125 +83,69 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
}
/*
- * mdev_register_device : Register a device
+ * mdev_register_parent: Register a device as parent for mdevs
+ * @parent: parent structure registered
* @dev: device structure representing parent device.
* @mdev_driver: Device driver to bind to the newly created mdev
*
- * Add device to list of registered parent devices.
* Returns a negative value on error, otherwise 0.
*/
-int mdev_register_device(struct device *dev, struct mdev_driver *mdev_driver)
+int mdev_register_parent(struct mdev_parent *parent, struct device *dev,
+ struct mdev_driver *mdev_driver)
{
- int ret;
- struct mdev_parent *parent;
char *env_string = "MDEV_STATE=registered";
char *envp[] = { env_string, NULL };
+ int ret;
/* check for mandatory ops */
if (!mdev_driver->supported_type_groups)
return -EINVAL;
- dev = get_device(dev);
- if (!dev)
- return -EINVAL;
-
Why not held device here? What if some driver miss behave where it
registers device to mdev, but unloads without unregistering from mdev?
Thanks,
Kirti
- mutex_lock(&parent_list_lock);
-
- /* Check for duplicate */
- parent = __find_parent_device(dev);
- if (parent) {
- parent = NULL;
- ret = -EEXIST;
- goto add_dev_err;
- }
-
- parent = kzalloc(sizeof(*parent), GFP_KERNEL);
- if (!parent) {
- ret = -ENOMEM;
- goto add_dev_err;
- }
-
- kref_init(&parent->ref);
+ memset(parent, 0, sizeof(*parent));
init_rwsem(&parent->unreg_sem);
-
parent->dev = dev;
parent->mdev_driver = mdev_driver;
if (!mdev_bus_compat_class) {
mdev_bus_compat_class = class_compat_register("mdev_bus");
- if (!mdev_bus_compat_class) {
- ret = -ENOMEM;
- goto add_dev_err;
- }
+ if (!mdev_bus_compat_class)
+ return -ENOMEM;
}
ret = parent_create_sysfs_files(parent);
if (ret)
- goto add_dev_err;
+ return ret;
ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
if (ret)
dev_warn(dev, "Failed to create compatibility class link\n");
- list_add(&parent->next, &parent_list);
- mutex_unlock(&parent_list_lock);
-
dev_info(dev, "MDEV: Registered\n");
kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
-
return 0;
-
-add_dev_err:
- mutex_unlock(&parent_list_lock);
- if (parent)
- mdev_put_parent(parent);
- else
- put_device(dev);
- return ret;
}
-EXPORT_SYMBOL(mdev_register_device);
+EXPORT_SYMBOL(mdev_register_parent);
/*
- * mdev_unregister_device : Unregister a parent device
- * @dev: device structure representing parent device.
- *
- * Remove device from list of registered parent devices. Give a chance to free
- * existing mediated devices for given device.
+ * mdev_unregister_parent : Unregister a parent device
+ * @parent: parent structure to unregister
*/
-
-void mdev_unregister_device(struct device *dev)
+void mdev_unregister_parent(struct mdev_parent *parent)
{
- struct mdev_parent *parent;
char *env_string = "MDEV_STATE=unregistered";
char *envp[] = { env_string, NULL };
- mutex_lock(&parent_list_lock);
- parent = __find_parent_device(dev);
-
- if (!parent) {
- mutex_unlock(&parent_list_lock);
- return;
- }
- dev_info(dev, "MDEV: Unregistering\n");
-
- list_del(&parent->next);
- mutex_unlock(&parent_list_lock);
+ dev_info(parent->dev, "MDEV: Unregistering\n");
down_write(&parent->unreg_sem);
-
- class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
-
- device_for_each_child(dev, NULL, mdev_device_remove_cb);
-
+ class_compat_remove_link(mdev_bus_compat_class, parent->dev, NULL);
+ device_for_each_child(parent->dev, NULL, mdev_device_remove_cb);
parent_remove_sysfs_files(parent);
up_write(&parent->unreg_sem);
- mdev_put_parent(parent);
-
- /* We still have the caller's reference to use for the uevent */
- kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
+ kobject_uevent_env(&parent->dev->kobj, KOBJ_CHANGE, envp);
}
-EXPORT_SYMBOL(mdev_unregister_device);
+EXPORT_SYMBOL(mdev_unregister_parent);
static void mdev_device_release(struct device *dev)
{
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 7c9fc79f3d838..297f911fdc890 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -13,17 +13,6 @@
int mdev_bus_register(void);
void mdev_bus_unregister(void);
-struct mdev_parent {
- struct device *dev;
- struct mdev_driver *mdev_driver;
- struct kref ref;
- struct list_head next;
- struct kset *mdev_types_kset;
- struct list_head type_list;
- /* Synchronize device creation/removal with parent unregistration */
- struct rw_semaphore unreg_sem;
-};
-
struct mdev_type {
struct kobject kobj;
struct kobject *devices_kobj;
@@ -48,16 +37,4 @@ void mdev_remove_sysfs_files(struct mdev_device *mdev);
int mdev_device_create(struct mdev_type *kobj, const guid_t *uuid);
int mdev_device_remove(struct mdev_device *dev);
-void mdev_release_parent(struct kref *kref);
-
-static inline void mdev_get_parent(struct mdev_parent *parent)
-{
- kref_get(&parent->ref);
-}
-
-static inline void mdev_put_parent(struct mdev_parent *parent)
-{
- kref_put(&parent->ref, mdev_release_parent);
-}
-
#endif /* MDEV_PRIVATE_H */
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index 0ccfeb3dda245..becce814aabfb 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -83,7 +83,7 @@ static void mdev_type_release(struct kobject *kobj)
pr_debug("Releasing group %s\n", kobj->name);
/* Pairs with the get in add_mdev_supported_type() */
- mdev_put_parent(type->parent);
+ put_device(type->parent->dev);
kfree(type);
}
@@ -112,7 +112,7 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
type->kobj.kset = parent->mdev_types_kset;
type->parent = parent;
/* Pairs with the put in mdev_type_release() */
- mdev_get_parent(parent);
+ get_device(parent->dev);
type->type_group_id = type_group_id;
ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 555c1d015b5f0..327ce3e5c6b5f 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -23,6 +23,16 @@ struct mdev_device {
bool active;
};
+/* embedded into the struct device that the mdev devices hang off */
+struct mdev_parent {
+ struct device *dev;
+ struct mdev_driver *mdev_driver;
+ struct kset *mdev_types_kset;
+ struct list_head type_list;
+ /* Synchronize device creation/removal with parent unregistration */
+ struct rw_semaphore unreg_sem;
+};
+
static inline struct mdev_device *to_mdev_device(struct device *dev)
{
return container_of(dev, struct mdev_device, dev);
@@ -75,8 +85,9 @@ static inline const guid_t *mdev_uuid(struct mdev_device *mdev)
extern struct bus_type mdev_bus_type;
-int mdev_register_device(struct device *dev, struct mdev_driver *mdev_driver);
-void mdev_unregister_device(struct device *dev);
+int mdev_register_parent(struct mdev_parent *parent, struct device *dev,
+ struct mdev_driver *mdev_driver);
+void mdev_unregister_parent(struct mdev_parent *parent);
int mdev_register_driver(struct mdev_driver *drv);
void mdev_unregister_driver(struct mdev_driver *drv);
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index 344c2901a82bf..f0967a81eabe7 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -129,6 +129,7 @@ static dev_t mbochs_devt;
static struct class *mbochs_class;
static struct cdev mbochs_cdev;
static struct device mbochs_dev;
+static struct mdev_parent mbochs_parent;
static atomic_t mbochs_avail_mbytes;
static const struct vfio_device_ops mbochs_dev_ops;
@@ -1457,7 +1458,7 @@ static int __init mbochs_dev_init(void)
if (ret)
goto err_class;
- ret = mdev_register_device(&mbochs_dev, &mbochs_driver);
+ ret = mdev_register_parent(&mbochs_parent, &mbochs_dev, &mbochs_driver);
if (ret)
goto err_device;
@@ -1478,7 +1479,7 @@ static int __init mbochs_dev_init(void)
static void __exit mbochs_dev_exit(void)
{
mbochs_dev.bus = NULL;
- mdev_unregister_device(&mbochs_dev);
+ mdev_unregister_parent(&mbochs_parent);
device_unregister(&mbochs_dev);
mdev_unregister_driver(&mbochs_driver);
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index e8c46eb2e2468..8ab88a1d149cb 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -84,6 +84,7 @@ static dev_t mdpy_devt;
static struct class *mdpy_class;
static struct cdev mdpy_cdev;
static struct device mdpy_dev;
+static struct mdev_parent mdpy_parent;
static u32 mdpy_count;
static const struct vfio_device_ops mdpy_dev_ops;
@@ -766,7 +767,7 @@ static int __init mdpy_dev_init(void)
if (ret)
goto err_class;
- ret = mdev_register_device(&mdpy_dev, &mdpy_driver);
+ ret = mdev_register_parent(&mdpy_parent, &mdpy_dev, &mdpy_driver);
if (ret)
goto err_device;
@@ -787,7 +788,7 @@ static int __init mdpy_dev_init(void)
static void __exit mdpy_dev_exit(void)
{
mdpy_dev.bus = NULL;
- mdev_unregister_device(&mdpy_dev);
+ mdev_unregister_parent(&mdpy_parent);
device_unregister(&mdpy_dev);
mdev_unregister_driver(&mdpy_driver);
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index f42a59ed2e3fe..20136def93fdb 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -74,6 +74,7 @@ static struct mtty_dev {
struct cdev vd_cdev;
struct idr vd_idr;
struct device dev;
+ struct mdev_parent parent;
} mtty_dev;
struct mdev_region_info {
@@ -1352,7 +1353,8 @@ static int __init mtty_dev_init(void)
if (ret)
goto err_class;
- ret = mdev_register_device(&mtty_dev.dev, &mtty_driver);
+ ret = mdev_register_parent(&mtty_dev.parent, &mtty_dev.dev,
+ &mtty_driver);
if (ret)
goto err_device;
return 0;
@@ -1372,7 +1374,7 @@ static int __init mtty_dev_init(void)
static void __exit mtty_dev_exit(void)
{
mtty_dev.dev.bus = NULL;
- mdev_unregister_device(&mtty_dev.dev);
+ mdev_unregister_parent(&mtty_dev.parent);
device_unregister(&mtty_dev.dev);
idr_destroy(&mtty_dev.vd_idr);
