Expose the optional alias for an mdev device as a sysfs attribute.
This way, userspace tools such as udev may make use of the alias, for
example to create a netdevice name for the mdev.
Updated documentation for optional read only sysfs attribute.
Signed-off-by: Parav Pandit <[email protected]>
---
Changelog:
v2->v3:
- Merged sysfs documentation patch with sysfs addition
- Added more description for alias return value
v0->v1:
- Addressed comments from Cornelia Huck
- Updated commit description
---
Documentation/driver-api/vfio-mediated-device.rst | 9 +++++++++
drivers/vfio/mdev/mdev_sysfs.c | 13 +++++++++++++
2 files changed, 22 insertions(+)
diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 25eb7d5b834b..0b7d2bf843b6 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -270,6 +270,7 @@ Directories and Files Under the sysfs for Each mdev Device
|--- remove
|--- mdev_type {link to its type}
|--- vendor-specific-attributes [optional]
+ |--- alias
* remove (write only)
@@ -281,6 +282,14 @@ Example::
# echo 1 > /sys/bus/mdev/devices/$mdev_UUID/remove
+* alias (read only, optional)
+Whenever a parent requested to generate an alias, each mdev device of such
+parent is assigned unique alias by the mdev core.
+This file shows the alias of the mdev device.
+
+Reading file either returns valid alias when assigned or returns error code
+-EOPNOTSUPP when unsupported.
+
Mediated device Hot plug
------------------------
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index 43afe0e80b76..59f4e3cc5233 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -246,7 +246,20 @@ static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_WO(remove);
+static ssize_t alias_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct mdev_device *dev = mdev_from_dev(device);
+
+ if (!dev->alias)
+ return -EOPNOTSUPP;
+
+ return sprintf(buf, "%s\n", dev->alias);
+}
+static DEVICE_ATTR_RO(alias);
+
static const struct attribute *mdev_device_attrs[] = {
+ &dev_attr_alias.attr,
&dev_attr_remove.attr,
NULL,
};
--
2.19.2
On Sun, 1 Sep 2019 23:24:34 -0500
Parav Pandit <[email protected]> wrote:
> Expose the optional alias for an mdev device as a sysfs attribute.
> This way, userspace tools such as udev may make use of the alias, for
> example to create a netdevice name for the mdev.
>
> Updated documentation for optional read only sysfs attribute.
>
> Signed-off-by: Parav Pandit <[email protected]>
>
> ---
> Changelog:
> v2->v3:
> - Merged sysfs documentation patch with sysfs addition
> - Added more description for alias return value
> v0->v1:
> - Addressed comments from Cornelia Huck
> - Updated commit description
> ---
> Documentation/driver-api/vfio-mediated-device.rst | 9 +++++++++
> drivers/vfio/mdev/mdev_sysfs.c | 13 +++++++++++++
> 2 files changed, 22 insertions(+)
>
(...)
> @@ -281,6 +282,14 @@ Example::
>
> # echo 1 > /sys/bus/mdev/devices/$mdev_UUID/remove
>
> +* alias (read only, optional)
> +Whenever a parent requested to generate an alias, each mdev device of such
s/such/that/
> +parent is assigned unique alias by the mdev core.
s/unique alias/a unique alias/
> +This file shows the alias of the mdev device.
> +
> +Reading file either returns valid alias when assigned or returns error code
s/file/this file/
s/valid alias/a valid alias/
s/error code/the error code/
> +-EOPNOTSUPP when unsupported.
> +
> Mediated device Hot plug
> ------------------------
With the nits above fixed,
Reviewed-by: Cornelia Huck <[email protected]>