On 6/2/2022 10:49 PM, Eric Farman wrote:
From: Jason Gunthorpe <jgg@xxxxxxxxxx>
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.
Cc: Kirti Wankhede <kwankhede@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Cc: Jason Herne <jjherne@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Link: https://lore.kernel.org/r/7-v3-57c1502c62fd+2190-ccw_mdev_jgg@xxxxxxxxxx/
[farman: added Cc: tags]
Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
---
.../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 f410a1cd98bb..a4f7f1362fa8 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);
};
This patch conflicts with Christoph Hellwig's patch. I see
'supported_type_groups' is not is above structure, I beleive that your
patch is applied on top of Christoph's patch series.
but then in below part of code, 'add_mdev_supported_type' has also being
removed in Christoph's patch. So this patch would not get applied cleanly.
Thanks,
Kirti
+/* 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 14655215417b..0ce1bb3dabd0 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);
};
