Many of the mdev drivers use a simple counter for keeping track of the available instances. Move this code to the core code and store the counter in the mdev_type. Implement it using correct locking, fixing mdpy.
Drivers provide a get_available() callback to set the number of available instances for their mtypes which is fixed at registration time. The core provides a standard sysfs attribute to return the available_instances.
Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Jason Gunthorpe jgg@nvidia.com --- .../driver-api/vfio-mediated-device.rst | 4 +- drivers/s390/cio/vfio_ccw_drv.c | 1 - drivers/s390/cio/vfio_ccw_ops.c | 26 ++++--------- drivers/s390/cio/vfio_ccw_private.h | 2 - drivers/s390/crypto/vfio_ap_ops.c | 32 ++++------------ drivers/s390/crypto/vfio_ap_private.h | 2 - drivers/vfio/mdev/mdev_core.c | 11 +++++- drivers/vfio/mdev/mdev_private.h | 2 + drivers/vfio/mdev/mdev_sysfs.c | 37 +++++++++++++++++++ include/linux/mdev.h | 2 + samples/vfio-mdev/mdpy.c | 22 +++-------- 11 files changed, 76 insertions(+), 65 deletions(-)
diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst index f410a1cd98bb06..a4f7f1362fa8a5 100644 --- a/Documentation/driver-api/vfio-mediated-device.rst +++ b/Documentation/driver-api/vfio-mediated-device.rst @@ -106,6 +106,7 @@ structure to represent a mediated device's driver:: int (*probe) (struct mdev_device *dev); void (*remove) (struct mdev_device *dev); struct device_driver driver; + unsigned int (*get_available)(struct mdev_type *mtype); };
A mediated bus driver for mdev should use this structure in the function calls @@ -232,7 +233,8 @@ Directories and files under the sysfs for Each Physical Device * available_instances
This attribute should show the number of devices of type <type-id> that can be - created. + created. Drivers can supply a get_available() function pointer to have the + core code create and maintain this sysfs automatically.
* [device]
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index 769edbbd164313..df9e1e265bca1a 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -106,7 +106,6 @@ static struct vfio_ccw_private *vfio_ccw_alloc_private(struct subchannel *sch) INIT_LIST_HEAD(&private->crw); INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo); INIT_WORK(&private->crw_work, vfio_ccw_crw_todo); - atomic_set(&private->avail, 1);
private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1), GFP_KERNEL); diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c index a7f642be9c8898..97df5c711736c4 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -70,20 +70,9 @@ static ssize_t name_show(struct mdev_type *mtype, } static MDEV_TYPE_ATTR_RO(name);
-static ssize_t available_instances_show(struct mdev_type *mtype, - struct mdev_type_attribute *attr, - char *buf) -{ - struct vfio_ccw_private *private = - dev_get_drvdata(mtype_get_parent_dev(mtype)); - - return sprintf(buf, "%d\n", atomic_read(&private->avail)); -} -static MDEV_TYPE_ATTR_RO(available_instances);
static struct attribute *mdev_types_attrs[] = { &mdev_type_attr_name.attr, - &mdev_type_attr_available_instances.attr, NULL, };
@@ -102,9 +91,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev) struct vfio_ccw_private *private = dev_get_drvdata(mdev->dev.parent); int ret;
- if (atomic_dec_if_positive(&private->avail) < 0) - return -EPERM; - memset(&private->vdev, 0, sizeof(private->vdev)); vfio_init_group_dev(&private->vdev, &mdev->dev, &vfio_ccw_dev_ops); @@ -118,13 +104,12 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev)
ret = vfio_register_emulated_iommu_dev(&private->vdev); if (ret) - goto err_atomic; + goto err_init; dev_set_drvdata(&mdev->dev, private); return 0;
-err_atomic: +err_init: vfio_uninit_group_dev(&private->vdev); - atomic_inc(&private->avail); private->mdev = NULL; return ret; } @@ -141,7 +126,6 @@ static void vfio_ccw_mdev_remove(struct mdev_device *mdev) vfio_unregister_group_dev(&private->vdev); vfio_uninit_group_dev(&private->vdev); private->mdev = NULL; - atomic_inc(&private->avail); }
static int vfio_ccw_mdev_open_device(struct vfio_device *vdev) @@ -610,6 +594,11 @@ static void vfio_ccw_mdev_request(struct vfio_device *vdev, unsigned int count) } }
+static unsigned int vfio_ccw_get_available(struct mdev_type *mtype) +{ + return 1; +} + static const struct vfio_device_ops vfio_ccw_dev_ops = { .open_device = vfio_ccw_mdev_open_device, .close_device = vfio_ccw_mdev_close_device, @@ -627,6 +616,7 @@ struct mdev_driver vfio_ccw_mdev_driver = { }, .probe = vfio_ccw_mdev_probe, .remove = vfio_ccw_mdev_remove, + .get_available = vfio_ccw_get_available, };
static const struct mdev_parent_ops vfio_ccw_mdev_ops = { diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h index 5e98eacdf31074..bbc97eb9d9c6fc 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -72,7 +72,6 @@ struct vfio_ccw_crw { * @sch: pointer to the subchannel * @state: internal state of the device * @completion: synchronization helper of the I/O completion - * @avail: available for creating a mediated device * @mdev: pointer to the mediated device * @nb: notifier for vfio events * @io_region: MMIO region to input/output I/O arguments/results @@ -96,7 +95,6 @@ struct vfio_ccw_private { struct subchannel *sch; int state; struct completion *completion; - atomic_t avail; struct mdev_device *mdev; struct notifier_block nb; struct ccw_io_region *io_region; diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index f80246b30aff30..b6eaee24f798a8 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -333,14 +333,9 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev) struct ap_matrix_mdev *matrix_mdev; int ret;
- if ((atomic_dec_if_positive(&matrix_dev->available_instances) < 0)) - return -EPERM; - matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL); - if (!matrix_mdev) { - ret = -ENOMEM; - goto err_dec_available; - } + if (!matrix_mdev) + return -ENOMEM; vfio_init_group_dev(&matrix_mdev->vdev, &mdev->dev, &vfio_ap_matrix_dev_ops);
@@ -363,8 +358,6 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev) mutex_unlock(&matrix_dev->lock); vfio_uninit_group_dev(&matrix_mdev->vdev); kfree(matrix_mdev); -err_dec_available: - atomic_inc(&matrix_dev->available_instances); return ret; }
@@ -380,7 +373,6 @@ static void vfio_ap_mdev_remove(struct mdev_device *mdev) mutex_unlock(&matrix_dev->lock); vfio_uninit_group_dev(&matrix_mdev->vdev); kfree(matrix_mdev); - atomic_inc(&matrix_dev->available_instances); }
static ssize_t name_show(struct mdev_type *mtype, @@ -391,20 +383,8 @@ static ssize_t name_show(struct mdev_type *mtype,
static MDEV_TYPE_ATTR_RO(name);
-static ssize_t available_instances_show(struct mdev_type *mtype, - struct mdev_type_attribute *attr, - char *buf) -{ - return sprintf(buf, "%d\n", - atomic_read(&matrix_dev->available_instances)); -} - -static MDEV_TYPE_ATTR_RO(available_instances); - - static struct attribute *vfio_ap_mdev_type_attrs[] = { &mdev_type_attr_name.attr, - &mdev_type_attr_available_instances.attr, NULL, };
@@ -1359,6 +1339,11 @@ static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev, return ret; }
+static unsigned int vfio_ap_mdev_get_available(struct mdev_type *mtype) +{ + return MAX_ZDEV_ENTRIES_EXT; +} + static const struct vfio_device_ops vfio_ap_matrix_dev_ops = { .open_device = vfio_ap_mdev_open_device, .close_device = vfio_ap_mdev_close_device, @@ -1374,6 +1359,7 @@ static struct mdev_driver vfio_ap_matrix_driver = { }, .probe = vfio_ap_mdev_probe, .remove = vfio_ap_mdev_remove, + .get_available = vfio_ap_mdev_get_available, };
static const struct mdev_parent_ops vfio_ap_matrix_ops = { @@ -1387,8 +1373,6 @@ int vfio_ap_mdev_register(void) { int ret;
- atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT); - ret = mdev_register_driver(&vfio_ap_matrix_driver); if (ret) return ret; diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h index 77760e2b546fe6..dd87c84605bcb6 100644 --- a/drivers/s390/crypto/vfio_ap_private.h +++ b/drivers/s390/crypto/vfio_ap_private.h @@ -28,7 +28,6 @@ /** * ap_matrix_dev - the AP matrix device structure * @device: generic device structure associated with the AP matrix device - * @available_instances: number of mediated matrix devices that can be created * @info: the struct containing the output from the PQAP(QCI) instruction * mdev_list: the list of mediated matrix devices created * lock: mutex for locking the AP matrix device. This lock will be @@ -39,7 +38,6 @@ */ struct ap_matrix_dev { struct device device; - atomic_t available_instances; struct ap_config_info info; struct list_head mdev_list; struct mutex lock; diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c index c3018e8e6d3258..bb27ca0db948ca 100644 --- a/drivers/vfio/mdev/mdev_core.c +++ b/drivers/vfio/mdev/mdev_core.c @@ -25,7 +25,7 @@ static DEFINE_MUTEX(parent_list_lock); static struct class_compat *mdev_bus_compat_class;
static LIST_HEAD(mdev_list); -static DEFINE_MUTEX(mdev_list_lock); +DEFINE_MUTEX(mdev_list_lock);
struct device *mdev_parent_dev(struct mdev_device *mdev) { @@ -245,6 +245,7 @@ static void mdev_device_release(struct device *dev)
mutex_lock(&mdev_list_lock); list_del(&mdev->next); + mdev->type->available++; mutex_unlock(&mdev_list_lock);
dev_dbg(&mdev->dev, "MDEV: destroying\n"); @@ -268,6 +269,14 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid) } }
+ if (drv && drv->get_available) { + if (!type->available) { + mutex_unlock(&mdev_list_lock); + return -EUSERS; + } + type->available--; + } + mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); if (!mdev) { mutex_unlock(&mdev_list_lock); diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h index afbad7b0a14a17..83586b07023334 100644 --- a/drivers/vfio/mdev/mdev_private.h +++ b/drivers/vfio/mdev/mdev_private.h @@ -29,6 +29,7 @@ struct mdev_type { struct kobject *devices_kobj; struct mdev_parent *parent; struct list_head next; + unsigned int available; unsigned int type_group_id; };
@@ -38,6 +39,7 @@ struct mdev_type { container_of(_kobj, struct mdev_type, kobj)
extern struct mdev_driver vfio_mdev_driver; +extern struct mutex mdev_list_lock;
int parent_create_sysfs_files(struct mdev_parent *parent); void parent_remove_sysfs_files(struct mdev_parent *parent); diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c index d4b99440d19e9a..b3129dfc27ef7d 100644 --- a/drivers/vfio/mdev/mdev_sysfs.c +++ b/drivers/vfio/mdev/mdev_sysfs.c @@ -93,8 +93,41 @@ static struct attribute_group mdev_type_std_group = { .attrs = mdev_types_std_attrs, };
+/* mdev_type attribute used by drivers that have an get_available() op */ +static ssize_t available_instances_show(struct mdev_type *mtype, + struct mdev_type_attribute *attr, + char *buf) +{ + unsigned int available; + + mutex_lock(&mdev_list_lock); + available = mtype->available; + mutex_unlock(&mdev_list_lock); + + return sysfs_emit(buf, "%u\n", available); +} +static MDEV_TYPE_ATTR_RO(available_instances); +static umode_t available_instances_is_visible(struct kobject *kobj, + struct attribute *attr, int n) +{ + struct mdev_type *type = to_mdev_type(kobj); + + if (!type->parent->ops->device_driver->get_available) + return 0; + return attr->mode; +} +static struct attribute *mdev_types_name_attrs[] = { + &mdev_type_attr_available_instances.attr, + NULL, +}; +static struct attribute_group mdev_type_available_instances_group = { + .attrs = mdev_types_name_attrs, + .is_visible = available_instances_is_visible, +}; + static const struct attribute_group *mdev_type_groups[] = { &mdev_type_std_group, + &mdev_type_available_instances_group, NULL, };
@@ -136,6 +169,10 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent, mdev_get_parent(parent); type->type_group_id = type_group_id;
+ if (parent->ops->device_driver->get_available) + type->available = + parent->ops->device_driver->get_available(type); + ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL, "%s-%s", dev_driver_string(parent->dev), group->name); diff --git a/include/linux/mdev.h b/include/linux/mdev.h index 8a5fc5d54f9b76..7cadbbac7de9d0 100644 --- a/include/linux/mdev.h +++ b/include/linux/mdev.h @@ -120,12 +120,14 @@ struct mdev_type_attribute { * @probe: called when new device created * @remove: called when device removed * @driver: device driver structure + * @get_available: Return the max number of instances that can be created * **/ struct mdev_driver { int (*probe)(struct mdev_device *dev); void (*remove)(struct mdev_device *dev); struct device_driver driver; + unsigned int (*get_available)(struct mdev_type *mtype); };
static inline void *mdev_get_drvdata(struct mdev_device *mdev) diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index 402a7ebe656371..d7da6ed3565705 100644 --- a/samples/vfio-mdev/mdpy.c +++ b/samples/vfio-mdev/mdpy.c @@ -84,7 +84,6 @@ static dev_t mdpy_devt; static struct class *mdpy_class; static struct cdev mdpy_cdev; static struct device mdpy_dev; -static u32 mdpy_count; static const struct vfio_device_ops mdpy_dev_ops;
/* State of each mdev device */ @@ -225,9 +224,6 @@ static int mdpy_probe(struct mdev_device *mdev) u32 fbsize; int ret;
- if (mdpy_count >= max_devices) - return -ENOMEM; - mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL); if (mdev_state == NULL) return -ENOMEM; @@ -256,8 +252,6 @@ static int mdpy_probe(struct mdev_device *mdev) mdpy_create_config_space(mdev_state); mdpy_reset(mdev_state);
- mdpy_count++; - ret = vfio_register_emulated_iommu_dev(&mdev_state->vdev); if (ret) goto err_mem; @@ -284,8 +278,6 @@ static void mdpy_remove(struct mdev_device *mdev) kfree(mdev_state->vconfig); vfio_uninit_group_dev(&mdev_state->vdev); kfree(mdev_state); - - mdpy_count--; }
static ssize_t mdpy_read(struct vfio_device *vdev, char __user *buf, @@ -662,18 +654,10 @@ static ssize_t description_show(struct mdev_type *mtype, } static MDEV_TYPE_ATTR_RO(description);
-static ssize_t available_instances_show(struct mdev_type *mtype, - struct mdev_type_attribute *attr, - char *buf) -{ - return sprintf(buf, "%d\n", max_devices - mdpy_count); -} -static MDEV_TYPE_ATTR_RO(available_instances);
static struct attribute *mdev_types_attrs[] = { &mdev_type_attr_name.attr, &mdev_type_attr_description.attr, - &mdev_type_attr_available_instances.attr, NULL, };
@@ -706,6 +690,11 @@ static const struct vfio_device_ops mdpy_dev_ops = { .mmap = mdpy_mmap, };
+static unsigned int mdpy_get_available(struct mdev_type *mtype) +{ + return max_devices; +} + static struct mdev_driver mdpy_driver = { .driver = { .name = "mdpy", @@ -715,6 +704,7 @@ static struct mdev_driver mdpy_driver = { }, .probe = mdpy_probe, .remove = mdpy_remove, + .get_available = mdpy_get_available, };
static const struct mdev_parent_ops mdev_fops = {