| Message ID | 20220923092652.100656-15-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/14] drm/i915/gvt: fix a memory leak in intel_gvt_init_vgpu_types | expand |
On Fri, 2022-09-23 at 11:26 +0200, Christoph Hellwig wrote: > From: Jason Gunthorpe <jgg@nvidia.com> > > 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_parent. Implement it using correct locking, fixing mdpy. > > Drivers just provide the value in the mdev_driver at registration > time > and the core code takes care of maintaining it and exposing the value > in > sysfs. > > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> > [hch: count instances per-parent instead of per-type, use an atomic_t > to avoid taking mdev_list_lock in the show method] > Signed-off-by: Christoph Hellwig <hch@lst.de> > Reviewed-by: Kevin Tian <kevin.tian@intel.com> > Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> > --- > drivers/s390/cio/vfio_ccw_drv.c | 1 - > drivers/s390/cio/vfio_ccw_ops.c | 15 +-------------- > drivers/s390/cio/vfio_ccw_private.h | 2 -- > drivers/s390/crypto/vfio_ap_ops.c | 13 +------------ > drivers/s390/crypto/vfio_ap_private.h | 2 -- > drivers/vfio/mdev/mdev_core.c | 22 +++++++++++++++++++--- > drivers/vfio/mdev/mdev_sysfs.c | 5 ++++- > include/linux/mdev.h | 3 +++ > samples/vfio-mdev/mdpy.c | 22 ++++------------------ > 9 files changed, 32 insertions(+), 53 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_drv.c > b/drivers/s390/cio/vfio_ccw_drv.c > index e5f21c725326b..7f5402fe857a2 100644 > --- a/drivers/s390/cio/vfio_ccw_drv.c > +++ b/drivers/s390/cio/vfio_ccw_drv.c > @@ -141,7 +141,6 @@ 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 559ca18055928..6ae4d012d8008 100644 > --- a/drivers/s390/cio/vfio_ccw_ops.c > +++ b/drivers/s390/cio/vfio_ccw_ops.c > @@ -44,13 +44,6 @@ static void vfio_ccw_dma_unmap(struct vfio_device > *vdev, u64 iova, u64 length) > vfio_ccw_mdev_reset(private); > } > > -static unsigned int vfio_ccw_get_available(struct mdev_type *mtype) > -{ > - struct vfio_ccw_private *private = dev_get_drvdata(mtype- > >parent->dev); > - > - return atomic_read(&private->avail); > -} > - > static int vfio_ccw_mdev_init_dev(struct vfio_device *vdev) > { > struct vfio_ccw_private *private = > @@ -68,9 +61,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device > *mdev) > if (private->state == VFIO_CCW_STATE_NOT_OPER) > return -ENODEV; > > - if (atomic_dec_if_positive(&private->avail) < 0) > - return -EPERM; > - > ret = vfio_init_device(&private->vdev, &mdev->dev, > &vfio_ccw_dev_ops); > if (ret) > return ret; > @@ -88,7 +78,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device > *mdev) > > err_put_vdev: > vfio_put_device(&private->vdev); > - atomic_inc(&private->avail); > return ret; > } > > @@ -130,8 +119,6 @@ static void vfio_ccw_mdev_remove(struct > mdev_device *mdev) > * cycle. > */ > wait_for_completion(&private->release_comp); > - > - atomic_inc(&private->avail); > } > > static int vfio_ccw_mdev_open_device(struct vfio_device *vdev) > @@ -605,6 +592,7 @@ static const struct vfio_device_ops > vfio_ccw_dev_ops = { > > struct mdev_driver vfio_ccw_mdev_driver = { > .device_api = VFIO_DEVICE_API_CCW_STRING, > + .max_instances = 1, > .driver = { > .name = "vfio_ccw_mdev", > .owner = THIS_MODULE, > @@ -612,5 +600,4 @@ struct mdev_driver vfio_ccw_mdev_driver = { > }, > .probe = vfio_ccw_mdev_probe, > .remove = vfio_ccw_mdev_remove, > - .get_available = vfio_ccw_get_available, > }; > diff --git a/drivers/s390/cio/vfio_ccw_private.h > b/drivers/s390/cio/vfio_ccw_private.h > index 52caa721ec06c..bd5fb81456af8 100644 > --- a/drivers/s390/cio/vfio_ccw_private.h > +++ b/drivers/s390/cio/vfio_ccw_private.h > @@ -73,7 +73,6 @@ 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 > * @io_region: MMIO region to input/output I/O arguments/results > * @io_mutex: protect against concurrent update of I/O regions > * @region: additional regions for other subchannel operations > @@ -97,7 +96,6 @@ struct vfio_ccw_private { > struct subchannel *sch; > int state; > struct completion *completion; > - atomic_t avail; > struct ccw_io_region *io_region; > struct mutex io_mutex; > struct vfio_ccw_region *region; > diff --git a/drivers/s390/crypto/vfio_ap_ops.c > b/drivers/s390/crypto/vfio_ap_ops.c > index 8606f5d75188c..2884189f38771 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -689,9 +689,6 @@ static int vfio_ap_mdev_init_dev(struct > vfio_device *vdev) > struct ap_matrix_mdev *matrix_mdev = > container_of(vdev, struct ap_matrix_mdev, vdev); > > - if ((atomic_dec_if_positive(&matrix_dev->available_instances) > < 0)) > - return -EPERM; > - > matrix_mdev->mdev = to_mdev_device(vdev->dev); > vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix); > matrix_mdev->pqap_hook = handle_pqap; > @@ -770,7 +767,6 @@ static void vfio_ap_mdev_unlink_fr_queues(struct > ap_matrix_mdev *matrix_mdev) > > static void vfio_ap_mdev_release_dev(struct vfio_device *vdev) > { > - atomic_inc(&matrix_dev->available_instances); > vfio_free_device(vdev); > } > > @@ -790,11 +786,6 @@ static void vfio_ap_mdev_remove(struct > mdev_device *mdev) > vfio_put_device(&matrix_mdev->vdev); > } > > -static unsigned int vfio_ap_mdev_get_available(struct mdev_type > *mtype) > -{ > - return atomic_read(&matrix_dev->available_instances); > -} > - > #define MDEV_SHARING_ERR "Userspace may not re-assign queue > %02lx.%04lx " \ > "already assigned to %s" > > @@ -1772,6 +1763,7 @@ static const struct vfio_device_ops > vfio_ap_matrix_dev_ops = { > > static struct mdev_driver vfio_ap_matrix_driver = { > .device_api = VFIO_DEVICE_API_AP_STRING, > + .max_instances = MAX_ZDEV_ENTRIES_EXT, > .driver = { > .name = "vfio_ap_mdev", > .owner = THIS_MODULE, > @@ -1780,15 +1772,12 @@ 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, > }; > > 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 441dc8dda380b..2eddd5f34ed34 100644 > --- a/drivers/s390/crypto/vfio_ap_private.h > +++ b/drivers/s390/crypto/vfio_ap_private.h > @@ -29,7 +29,6 @@ > * struct ap_matrix_dev - Contains the data for the matrix device. > * > * @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 > * @mdevs_lock: mutex for locking the AP matrix device. This lock > will be > @@ -46,7 +45,6 @@ > */ > struct ap_matrix_dev { > struct device device; > - atomic_t available_instances; > struct ap_config_info info; > struct list_head mdev_list; > struct mutex mdevs_lock; /* serializes access to each > ap_matrix_mdev */ > diff --git a/drivers/vfio/mdev/mdev_core.c > b/drivers/vfio/mdev/mdev_core.c > index 93f8caf2e5f77..58f91b3bd670c 100644 > --- a/drivers/vfio/mdev/mdev_core.c > +++ b/drivers/vfio/mdev/mdev_core.c > @@ -70,6 +70,7 @@ int mdev_register_parent(struct mdev_parent > *parent, struct device *dev, > parent->mdev_driver = mdev_driver; > parent->types = types; > parent->nr_types = nr_types; > + atomic_set(&parent->available_instances, mdev_driver- > >max_instances); > > if (!mdev_bus_compat_class) { > mdev_bus_compat_class = > class_compat_register("mdev_bus"); > @@ -115,14 +116,17 @@ EXPORT_SYMBOL(mdev_unregister_parent); > static void mdev_device_release(struct device *dev) > { > struct mdev_device *mdev = to_mdev_device(dev); > - > - /* Pairs with the get in mdev_device_create() */ > - kobject_put(&mdev->type->kobj); > + struct mdev_parent *parent = mdev->type->parent; > > mutex_lock(&mdev_list_lock); > list_del(&mdev->next); > + if (!parent->mdev_driver->get_available) > + atomic_inc(&parent->available_instances); > mutex_unlock(&mdev_list_lock); > > + /* Pairs with the get in mdev_device_create() */ > + kobject_put(&mdev->type->kobj); > + > dev_dbg(&mdev->dev, "MDEV: destroying\n"); > kfree(mdev); > } > @@ -144,6 +148,18 @@ int mdev_device_create(struct mdev_type *type, > const guid_t *uuid) > } > } > > + if (!drv->get_available) { > + /* > + * Note: that non-atomic read and dec is fine here > because > + * all modifications are under mdev_list_lock. > + */ > + if (!atomic_read(&parent->available_instances)) { > + mutex_unlock(&mdev_list_lock); > + return -EUSERS; > + } > + atomic_dec(&parent->available_instances); > + } > + > mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); > if (!mdev) { > mutex_unlock(&mdev_list_lock); > diff --git a/drivers/vfio/mdev/mdev_sysfs.c > b/drivers/vfio/mdev/mdev_sysfs.c > index 658b3bf5ed0bf..abe3359dd477f 100644 > --- a/drivers/vfio/mdev/mdev_sysfs.c > +++ b/drivers/vfio/mdev/mdev_sysfs.c > @@ -108,7 +108,10 @@ static ssize_t available_instances_show(struct > mdev_type *mtype, > { > struct mdev_driver *drv = mtype->parent->mdev_driver; > > - return sysfs_emit(buf, "%u\n", drv->get_available(mtype)); > + if (drv->get_available) > + return sysfs_emit(buf, "%u\n", drv- > >get_available(mtype)); > + return sysfs_emit(buf, "%u\n", > + atomic_read(&mtype->parent- > >available_instances)); > } > static MDEV_TYPE_ATTR_RO(available_instances); > > diff --git a/include/linux/mdev.h b/include/linux/mdev.h > index 33674cb5ed5d4..139d05b26f820 100644 > --- a/include/linux/mdev.h > +++ b/include/linux/mdev.h > @@ -45,6 +45,7 @@ struct mdev_parent { > struct rw_semaphore unreg_sem; > struct mdev_type **types; > unsigned int nr_types; > + atomic_t available_instances; > }; > > static inline struct mdev_device *to_mdev_device(struct device *dev) > @@ -55,6 +56,7 @@ static inline struct mdev_device > *to_mdev_device(struct device *dev) > /** > * struct mdev_driver - Mediated device driver > * @device_api: string to return for the device_api sysfs > + * @max_instances: maximum number of instances supported (optional) > * @probe: called when new device created > * @remove: called when device removed > * @get_available: Return the max number of instances that can be > created > @@ -63,6 +65,7 @@ static inline struct mdev_device > *to_mdev_device(struct device *dev) > **/ > struct mdev_driver { > const char *device_api; > + unsigned int max_instances; > int (*probe)(struct mdev_device *dev); > void (*remove)(struct mdev_device *dev); > unsigned int (*get_available)(struct mdev_type *mtype); > diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c > index a7cf59246ddd0..946e8cfde6fdd 100644 > --- a/samples/vfio-mdev/mdpy.c > +++ b/samples/vfio-mdev/mdpy.c > @@ -42,11 +42,6 @@ > > MODULE_LICENSE("GPL v2"); > > -static int max_devices = 4; > -module_param_named(count, max_devices, int, 0444); > -MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices"); > - > - > #define MDPY_TYPE_1 "vga" > #define MDPY_TYPE_2 "xga" > #define MDPY_TYPE_3 "hd" > @@ -93,7 +88,6 @@ 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; > > /* State of each mdev device */ > @@ -235,9 +229,6 @@ static int mdpy_init_dev(struct vfio_device > *vdev) > u32 fbsize; > int ret = -ENOMEM; > > - if (mdpy_count >= max_devices) > - return ret; > - > mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, > GFP_KERNEL); > if (!mdev_state->vconfig) > return ret; > @@ -257,8 +248,6 @@ static int mdpy_init_dev(struct vfio_device > *vdev) > > dev_info(vdev->dev, "%s: %s (%dx%d)\n", __func__, type- > >type.pretty_name, > type->width, type->height); > - > - mdpy_count++; > return 0; > > out_vconfig: > @@ -292,7 +281,6 @@ static void mdpy_release_dev(struct vfio_device > *vdev) > struct mdev_state *mdev_state = > container_of(vdev, struct mdev_state, vdev); > > - mdpy_count--; > vfree(mdev_state->memblk); > kfree(mdev_state->vconfig); > vfio_free_device(vdev); > @@ -669,11 +657,6 @@ static ssize_t mdpy_show_description(struct > mdev_type *mtype, char *buf) > type->width, type->height); > } > > -static unsigned int mdpy_get_available(struct mdev_type *mtype) > -{ > - return max_devices - mdpy_count; > -} > - > static const struct vfio_device_ops mdpy_dev_ops = { > .init = mdpy_init_dev, > .release = mdpy_release_dev, > @@ -685,6 +668,7 @@ static const struct vfio_device_ops mdpy_dev_ops > = { > > static struct mdev_driver mdpy_driver = { > .device_api = VFIO_DEVICE_API_PCI_STRING, > + .max_instances = 4, > .driver = { > .name = "mdpy", > .owner = THIS_MODULE, > @@ -693,7 +677,6 @@ static struct mdev_driver mdpy_driver = { > }, > .probe = mdpy_probe, > .remove = mdpy_remove, > - .get_available = mdpy_get_available, > .show_description = mdpy_show_description, > }; > > @@ -770,5 +753,8 @@ static void __exit mdpy_dev_exit(void) > mdpy_class = NULL; > } > > +module_param_named(count, mdpy_driver.max_instances, int, 0444); > +MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices"); > + > module_init(mdpy_dev_init) > module_exit(mdpy_dev_exit)
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index e5f21c725326b..7f5402fe857a2 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -141,7 +141,6 @@ 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 559ca18055928..6ae4d012d8008 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -44,13 +44,6 @@ static void vfio_ccw_dma_unmap(struct vfio_device *vdev, u64 iova, u64 length) vfio_ccw_mdev_reset(private); } -static unsigned int vfio_ccw_get_available(struct mdev_type *mtype) -{ - struct vfio_ccw_private *private = dev_get_drvdata(mtype->parent->dev); - - return atomic_read(&private->avail); -} - static int vfio_ccw_mdev_init_dev(struct vfio_device *vdev) { struct vfio_ccw_private *private = @@ -68,9 +61,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev) if (private->state == VFIO_CCW_STATE_NOT_OPER) return -ENODEV; - if (atomic_dec_if_positive(&private->avail) < 0) - return -EPERM; - ret = vfio_init_device(&private->vdev, &mdev->dev, &vfio_ccw_dev_ops); if (ret) return ret; @@ -88,7 +78,6 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev) err_put_vdev: vfio_put_device(&private->vdev); - atomic_inc(&private->avail); return ret; } @@ -130,8 +119,6 @@ static void vfio_ccw_mdev_remove(struct mdev_device *mdev) * cycle. */ wait_for_completion(&private->release_comp); - - atomic_inc(&private->avail); } static int vfio_ccw_mdev_open_device(struct vfio_device *vdev) @@ -605,6 +592,7 @@ static const struct vfio_device_ops vfio_ccw_dev_ops = { struct mdev_driver vfio_ccw_mdev_driver = { .device_api = VFIO_DEVICE_API_CCW_STRING, + .max_instances = 1, .driver = { .name = "vfio_ccw_mdev", .owner = THIS_MODULE, @@ -612,5 +600,4 @@ struct mdev_driver vfio_ccw_mdev_driver = { }, .probe = vfio_ccw_mdev_probe, .remove = vfio_ccw_mdev_remove, - .get_available = vfio_ccw_get_available, }; diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h index 52caa721ec06c..bd5fb81456af8 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -73,7 +73,6 @@ 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 * @io_region: MMIO region to input/output I/O arguments/results * @io_mutex: protect against concurrent update of I/O regions * @region: additional regions for other subchannel operations @@ -97,7 +96,6 @@ struct vfio_ccw_private { struct subchannel *sch; int state; struct completion *completion; - atomic_t avail; struct ccw_io_region *io_region; struct mutex io_mutex; struct vfio_ccw_region *region; diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index 8606f5d75188c..2884189f38771 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -689,9 +689,6 @@ static int vfio_ap_mdev_init_dev(struct vfio_device *vdev) struct ap_matrix_mdev *matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev); - if ((atomic_dec_if_positive(&matrix_dev->available_instances) < 0)) - return -EPERM; - matrix_mdev->mdev = to_mdev_device(vdev->dev); vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix); matrix_mdev->pqap_hook = handle_pqap; @@ -770,7 +767,6 @@ static void vfio_ap_mdev_unlink_fr_queues(struct ap_matrix_mdev *matrix_mdev) static void vfio_ap_mdev_release_dev(struct vfio_device *vdev) { - atomic_inc(&matrix_dev->available_instances); vfio_free_device(vdev); } @@ -790,11 +786,6 @@ static void vfio_ap_mdev_remove(struct mdev_device *mdev) vfio_put_device(&matrix_mdev->vdev); } -static unsigned int vfio_ap_mdev_get_available(struct mdev_type *mtype) -{ - return atomic_read(&matrix_dev->available_instances); -} - #define MDEV_SHARING_ERR "Userspace may not re-assign queue %02lx.%04lx " \ "already assigned to %s" @@ -1772,6 +1763,7 @@ static const struct vfio_device_ops vfio_ap_matrix_dev_ops = { static struct mdev_driver vfio_ap_matrix_driver = { .device_api = VFIO_DEVICE_API_AP_STRING, + .max_instances = MAX_ZDEV_ENTRIES_EXT, .driver = { .name = "vfio_ap_mdev", .owner = THIS_MODULE, @@ -1780,15 +1772,12 @@ 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, }; 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 441dc8dda380b..2eddd5f34ed34 100644 --- a/drivers/s390/crypto/vfio_ap_private.h +++ b/drivers/s390/crypto/vfio_ap_private.h @@ -29,7 +29,6 @@ * struct ap_matrix_dev - Contains the data for the matrix device. * * @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 * @mdevs_lock: mutex for locking the AP matrix device. This lock will be @@ -46,7 +45,6 @@ */ struct ap_matrix_dev { struct device device; - atomic_t available_instances; struct ap_config_info info; struct list_head mdev_list; struct mutex mdevs_lock; /* serializes access to each ap_matrix_mdev */ diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c index 93f8caf2e5f77..58f91b3bd670c 100644 --- a/drivers/vfio/mdev/mdev_core.c +++ b/drivers/vfio/mdev/mdev_core.c @@ -70,6 +70,7 @@ int mdev_register_parent(struct mdev_parent *parent, struct device *dev, parent->mdev_driver = mdev_driver; parent->types = types; parent->nr_types = nr_types; + atomic_set(&parent->available_instances, mdev_driver->max_instances); if (!mdev_bus_compat_class) { mdev_bus_compat_class = class_compat_register("mdev_bus"); @@ -115,14 +116,17 @@ EXPORT_SYMBOL(mdev_unregister_parent); static void mdev_device_release(struct device *dev) { struct mdev_device *mdev = to_mdev_device(dev); - - /* Pairs with the get in mdev_device_create() */ - kobject_put(&mdev->type->kobj); + struct mdev_parent *parent = mdev->type->parent; mutex_lock(&mdev_list_lock); list_del(&mdev->next); + if (!parent->mdev_driver->get_available) + atomic_inc(&parent->available_instances); mutex_unlock(&mdev_list_lock); + /* Pairs with the get in mdev_device_create() */ + kobject_put(&mdev->type->kobj); + dev_dbg(&mdev->dev, "MDEV: destroying\n"); kfree(mdev); } @@ -144,6 +148,18 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid) } } + if (!drv->get_available) { + /* + * Note: that non-atomic read and dec is fine here because + * all modifications are under mdev_list_lock. + */ + if (!atomic_read(&parent->available_instances)) { + mutex_unlock(&mdev_list_lock); + return -EUSERS; + } + atomic_dec(&parent->available_instances); + } + mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); if (!mdev) { mutex_unlock(&mdev_list_lock); diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c index 658b3bf5ed0bf..abe3359dd477f 100644 --- a/drivers/vfio/mdev/mdev_sysfs.c +++ b/drivers/vfio/mdev/mdev_sysfs.c @@ -108,7 +108,10 @@ static ssize_t available_instances_show(struct mdev_type *mtype, { struct mdev_driver *drv = mtype->parent->mdev_driver; - return sysfs_emit(buf, "%u\n", drv->get_available(mtype)); + if (drv->get_available) + return sysfs_emit(buf, "%u\n", drv->get_available(mtype)); + return sysfs_emit(buf, "%u\n", + atomic_read(&mtype->parent->available_instances)); } static MDEV_TYPE_ATTR_RO(available_instances); diff --git a/include/linux/mdev.h b/include/linux/mdev.h index 33674cb5ed5d4..139d05b26f820 100644 --- a/include/linux/mdev.h +++ b/include/linux/mdev.h @@ -45,6 +45,7 @@ struct mdev_parent { struct rw_semaphore unreg_sem; struct mdev_type **types; unsigned int nr_types; + atomic_t available_instances; }; static inline struct mdev_device *to_mdev_device(struct device *dev) @@ -55,6 +56,7 @@ static inline struct mdev_device *to_mdev_device(struct device *dev) /** * struct mdev_driver - Mediated device driver * @device_api: string to return for the device_api sysfs + * @max_instances: maximum number of instances supported (optional) * @probe: called when new device created * @remove: called when device removed * @get_available: Return the max number of instances that can be created @@ -63,6 +65,7 @@ static inline struct mdev_device *to_mdev_device(struct device *dev) **/ struct mdev_driver { const char *device_api; + unsigned int max_instances; int (*probe)(struct mdev_device *dev); void (*remove)(struct mdev_device *dev); unsigned int (*get_available)(struct mdev_type *mtype); diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index a7cf59246ddd0..946e8cfde6fdd 100644 --- a/samples/vfio-mdev/mdpy.c +++ b/samples/vfio-mdev/mdpy.c @@ -42,11 +42,6 @@ MODULE_LICENSE("GPL v2"); -static int max_devices = 4; -module_param_named(count, max_devices, int, 0444); -MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices"); - - #define MDPY_TYPE_1 "vga" #define MDPY_TYPE_2 "xga" #define MDPY_TYPE_3 "hd" @@ -93,7 +88,6 @@ 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; /* State of each mdev device */ @@ -235,9 +229,6 @@ static int mdpy_init_dev(struct vfio_device *vdev) u32 fbsize; int ret = -ENOMEM; - if (mdpy_count >= max_devices) - return ret; - mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, GFP_KERNEL); if (!mdev_state->vconfig) return ret; @@ -257,8 +248,6 @@ static int mdpy_init_dev(struct vfio_device *vdev) dev_info(vdev->dev, "%s: %s (%dx%d)\n", __func__, type->type.pretty_name, type->width, type->height); - - mdpy_count++; return 0; out_vconfig: @@ -292,7 +281,6 @@ static void mdpy_release_dev(struct vfio_device *vdev) struct mdev_state *mdev_state = container_of(vdev, struct mdev_state, vdev); - mdpy_count--; vfree(mdev_state->memblk); kfree(mdev_state->vconfig); vfio_free_device(vdev); @@ -669,11 +657,6 @@ static ssize_t mdpy_show_description(struct mdev_type *mtype, char *buf) type->width, type->height); } -static unsigned int mdpy_get_available(struct mdev_type *mtype) -{ - return max_devices - mdpy_count; -} - static const struct vfio_device_ops mdpy_dev_ops = { .init = mdpy_init_dev, .release = mdpy_release_dev, @@ -685,6 +668,7 @@ static const struct vfio_device_ops mdpy_dev_ops = { static struct mdev_driver mdpy_driver = { .device_api = VFIO_DEVICE_API_PCI_STRING, + .max_instances = 4, .driver = { .name = "mdpy", .owner = THIS_MODULE, @@ -693,7 +677,6 @@ static struct mdev_driver mdpy_driver = { }, .probe = mdpy_probe, .remove = mdpy_remove, - .get_available = mdpy_get_available, .show_description = mdpy_show_description, }; @@ -770,5 +753,8 @@ static void __exit mdpy_dev_exit(void) mdpy_class = NULL; } +module_param_named(count, mdpy_driver.max_instances, int, 0444); +MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices"); + module_init(mdpy_dev_init) module_exit(mdpy_dev_exit)