Move the "removable" attribute from USB to core in order to allow it to be
supported by other subsystem / buses. Individual buses that want to support
this attribute can opt-in by setting the supports_removable flag, and then
populating the removable property of the device while enumerating it. The
UAPI (location, symantics etc) for the attribute remains unchanged.
Signed-off-by: Rajat Jain <[email protected]>
Acked-by: Alan Stern <[email protected]>
Reviewed-by: Bjorn Helgaas <[email protected]>
---
v3: - Minor commit log / comments updated.
- use sysfs_emit()
- Rename local variable name (state -> loc)
- change supports_removable flag from bool to bitfield.
v2: Add documentation
Documentation/ABI/testing/sysfs-bus-usb | 11 -------
.../ABI/testing/sysfs-devices-removable | 17 ++++++++++
drivers/base/core.c | 28 ++++++++++++++++
drivers/usb/core/hub.c | 8 ++---
drivers/usb/core/sysfs.c | 24 --------------
drivers/usb/core/usb.c | 1 +
include/linux/device.h | 32 +++++++++++++++++++
include/linux/usb.h | 7 ----
8 files changed, 82 insertions(+), 46 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-devices-removable
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index bf2c1968525f..73eb23bc1f34 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -154,17 +154,6 @@ Description:
files hold a string value (enable or disable) indicating whether
or not USB3 hardware LPM U1 or U2 is enabled for the device.
-What: /sys/bus/usb/devices/.../removable
-Date: February 2012
-Contact: Matthew Garrett <[email protected]>
-Description:
- Some information about whether a given USB device is
- physically fixed to the platform can be inferred from a
- combination of hub descriptor bits and platform-specific data
- such as ACPI. This file will read either "removable" or
- "fixed" if the information is available, and "unknown"
- otherwise.
-
What: /sys/bus/usb/devices/.../ltm_capable
Date: July 2012
Contact: Sarah Sharp <[email protected]>
diff --git a/Documentation/ABI/testing/sysfs-devices-removable b/Documentation/ABI/testing/sysfs-devices-removable
new file mode 100644
index 000000000000..9dabcad7cdcd
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-removable
@@ -0,0 +1,17 @@
+What: /sys/devices/.../removable
+Date: Apr 2021
+Contact: Matthew Garrett <[email protected]>,
+ Rajat Jain <[email protected]>
+Description:
+ Information about whether a given device is physically fixed to
+ the platform. This is determined by the device's subsystem in a
+ bus / platform-specific way. This attribute is only present for
+ buses that can support determining such information:
+
+ "removable": The device is external / removable from the system.
+ "fixed": The device is internal / fixed to the system.
+ "unknown": The information is unavailable.
+
+ Currently this is only supported by USB (which infers the
+ information from a combination of hub descriptor bits and
+ platform-specific data such as ACPI).
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 4a8bf8cda52b..9e6bf9e71a7e 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2404,6 +2404,25 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RW(online);
+static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ const char *loc;
+
+ switch (dev->removable) {
+ case DEVICE_REMOVABLE:
+ loc = "removable";
+ break;
+ case DEVICE_FIXED:
+ loc = "fixed";
+ break;
+ default:
+ loc = "unknown";
+ }
+ return sysfs_emit(buf, "%s\n", loc);
+}
+static DEVICE_ATTR_RO(removable);
+
int device_add_groups(struct device *dev, const struct attribute_group **groups)
{
return sysfs_create_groups(&dev->kobj, groups);
@@ -2581,8 +2600,16 @@ static int device_add_attrs(struct device *dev)
goto err_remove_dev_online;
}
+ if (type && type->supports_removable) {
+ error = device_create_file(dev, &dev_attr_removable);
+ if (error)
+ goto err_remove_dev_waiting_for_supplier;
+ }
+
return 0;
+ err_remove_dev_waiting_for_supplier:
+ device_remove_file(dev, &dev_attr_waiting_for_supplier);
err_remove_dev_online:
device_remove_file(dev, &dev_attr_online);
err_remove_dev_groups:
@@ -2602,6 +2629,7 @@ static void device_remove_attrs(struct device *dev)
struct class *class = dev->class;
const struct device_type *type = dev->type;
+ device_remove_file(dev, &dev_attr_removable);
device_remove_file(dev, &dev_attr_waiting_for_supplier);
device_remove_file(dev, &dev_attr_online);
device_remove_groups(dev, dev->groups);
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b2bc4b7c4289..7a3c28b14ca1 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2443,11 +2443,11 @@ static void set_usb_port_removable(struct usb_device *udev)
*/
switch (hub->ports[udev->portnum - 1]->connect_type) {
case USB_PORT_CONNECT_TYPE_HOT_PLUG:
- udev->removable = USB_DEVICE_REMOVABLE;
+ dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
return;
case USB_PORT_CONNECT_TYPE_HARD_WIRED:
case USB_PORT_NOT_USED:
- udev->removable = USB_DEVICE_FIXED;
+ dev_set_removable(&udev->dev, DEVICE_FIXED);
return;
default:
break;
@@ -2472,9 +2472,9 @@ static void set_usb_port_removable(struct usb_device *udev)
}
if (removable)
- udev->removable = USB_DEVICE_REMOVABLE;
+ dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
else
- udev->removable = USB_DEVICE_FIXED;
+ dev_set_removable(&udev->dev, DEVICE_FIXED);
}
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 5a168ba9fc51..fa2e49d432ff 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -301,29 +301,6 @@ static ssize_t urbnum_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(urbnum);
-static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
- char *buf)
-{
- struct usb_device *udev;
- char *state;
-
- udev = to_usb_device(dev);
-
- switch (udev->removable) {
- case USB_DEVICE_REMOVABLE:
- state = "removable";
- break;
- case USB_DEVICE_FIXED:
- state = "fixed";
- break;
- default:
- state = "unknown";
- }
-
- return sprintf(buf, "%s\n", state);
-}
-static DEVICE_ATTR_RO(removable);
-
static ssize_t ltm_capable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -828,7 +805,6 @@ static struct attribute *dev_attrs[] = {
&dev_attr_avoid_reset_quirk.attr,
&dev_attr_authorized.attr,
&dev_attr_remove.attr,
- &dev_attr_removable.attr,
&dev_attr_ltm_capable.attr,
#ifdef CONFIG_OF
&dev_attr_devspec.attr,
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 62368c4ed37a..ce18e84528cf 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -569,6 +569,7 @@ struct device_type usb_device_type = {
#ifdef CONFIG_PM
.pm = &usb_device_pm_ops,
#endif
+ .supports_removable = true,
};
diff --git a/include/linux/device.h b/include/linux/device.h
index 38a2071cf776..7e87ab048307 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -93,6 +93,8 @@ struct device_type {
void (*release)(struct device *dev);
const struct dev_pm_ops *pm;
+
+ bool supports_removable:1; /* subsystem can classify removable/fixed */
};
/* interface for exporting device attributes */
@@ -350,6 +352,19 @@ enum dl_dev_state {
DL_DEV_UNBINDING,
};
+/**
+ * enum device_removable - Whether the device is removable. The criteria for a
+ * device to be classified as removable is determined by its subsystem or bus.
+ * @DEVICE_REMOVABLE_UNKNOWN: Device location is Unknown (default).
+ * @DEVICE_REMOVABLE: Device is removable by the user.
+ * @DEVICE_FIXED: Device is not removable by the user.
+ */
+enum device_removable {
+ DEVICE_REMOVABLE_UNKNOWN = 0,
+ DEVICE_REMOVABLE,
+ DEVICE_FIXED,
+};
+
/**
* struct dev_links_info - Device data related to device links.
* @suppliers: List of links to supplier devices.
@@ -431,6 +446,9 @@ struct dev_links_info {
* device (i.e. the bus driver that discovered the device).
* @iommu_group: IOMMU group the device belongs to.
* @iommu: Per device generic IOMMU runtime data
+ * @removable: Whether the device can be removed from the system. This
+ * should be set by the subsystem / bus driver that discovered
+ * the device.
*
* @offline_disabled: If set, the device is permanently online.
* @offline: Set after successful invocation of bus type's .offline().
@@ -544,6 +562,8 @@ struct device {
struct iommu_group *iommu_group;
struct dev_iommu *iommu;
+ enum device_removable removable;
+
bool offline_disabled:1;
bool offline:1;
bool of_node_reused:1;
@@ -782,6 +802,18 @@ static inline bool dev_has_sync_state(struct device *dev)
return false;
}
+static inline void dev_set_removable(struct device *dev,
+ enum device_removable removable)
+{
+ dev->removable = removable;
+}
+
+static inline bool dev_is_removable(struct device *dev)
+{
+ return dev && dev->type && dev->type->supports_removable
+ && dev->removable == DEVICE_REMOVABLE;
+}
+
/*
* High level routines for use by the bus drivers
*/
diff --git a/include/linux/usb.h b/include/linux/usb.h
index eaae24217e8a..b9bd664f44a1 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -473,12 +473,6 @@ struct usb_dev_state;
struct usb_tt;
-enum usb_device_removable {
- USB_DEVICE_REMOVABLE_UNKNOWN = 0,
- USB_DEVICE_REMOVABLE,
- USB_DEVICE_FIXED,
-};
-
enum usb_port_connect_type {
USB_PORT_CONNECT_TYPE_UNKNOWN = 0,
USB_PORT_CONNECT_TYPE_HOT_PLUG,
@@ -703,7 +697,6 @@ struct usb_device {
#endif
struct wusb_dev *wusb_dev;
int slot_id;
- enum usb_device_removable removable;
struct usb2_lpm_parameters l1_params;
struct usb3_lpm_parameters u1_params;
struct usb3_lpm_parameters u2_params;
--
2.31.1.607.g51e8a6a459-goog
Hello,
On Thu, May 13, 2021 at 6:55 AM Greg Kroah-Hartman
<[email protected]> wrote:
>
> On Wed, May 12, 2021 at 02:34:56PM -0700, Rajat Jain wrote:
> > Move the "removable" attribute from USB to core in order to allow it to be
> > supported by other subsystem / buses. Individual buses that want to support
> > this attribute can opt-in by setting the supports_removable flag, and then
> > populating the removable property of the device while enumerating it. The
> > UAPI (location, symantics etc) for the attribute remains unchanged.
> >
> > Signed-off-by: Rajat Jain <[email protected]>
> > Acked-by: Alan Stern <[email protected]>
> > Reviewed-by: Bjorn Helgaas <[email protected]>
> > ---
> > v3: - Minor commit log / comments updated.
> > - use sysfs_emit()
> > - Rename local variable name (state -> loc)
> > - change supports_removable flag from bool to bitfield.
> > v2: Add documentation
> >
> > Documentation/ABI/testing/sysfs-bus-usb | 11 -------
> > .../ABI/testing/sysfs-devices-removable | 17 ++++++++++
> > drivers/base/core.c | 28 ++++++++++++++++
> > drivers/usb/core/hub.c | 8 ++---
> > drivers/usb/core/sysfs.c | 24 --------------
> > drivers/usb/core/usb.c | 1 +
> > include/linux/device.h | 32 +++++++++++++++++++
> > include/linux/usb.h | 7 ----
> > 8 files changed, 82 insertions(+), 46 deletions(-)
> > create mode 100644 Documentation/ABI/testing/sysfs-devices-removable
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
> > index bf2c1968525f..73eb23bc1f34 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-usb
> > +++ b/Documentation/ABI/testing/sysfs-bus-usb
> > @@ -154,17 +154,6 @@ Description:
> > files hold a string value (enable or disable) indicating whether
> > or not USB3 hardware LPM U1 or U2 is enabled for the device.
> >
> > -What: /sys/bus/usb/devices/.../removable
> > -Date: February 2012
> > -Contact: Matthew Garrett <[email protected]>
> > -Description:
> > - Some information about whether a given USB device is
> > - physically fixed to the platform can be inferred from a
> > - combination of hub descriptor bits and platform-specific data
> > - such as ACPI. This file will read either "removable" or
> > - "fixed" if the information is available, and "unknown"
> > - otherwise.
> > -
> > What: /sys/bus/usb/devices/.../ltm_capable
> > Date: July 2012
> > Contact: Sarah Sharp <[email protected]>
> > diff --git a/Documentation/ABI/testing/sysfs-devices-removable b/Documentation/ABI/testing/sysfs-devices-removable
> > new file mode 100644
> > index 000000000000..9dabcad7cdcd
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-devices-removable
> > @@ -0,0 +1,17 @@
> > +What: /sys/devices/.../removable
>
> This should be "/sys/bus/devices/.../removable" perhaps? Or not? Is
> this moving in the existing USB cases?
>
> > +Date: Apr 2021
> > +Contact: Matthew Garrett <[email protected]>,
>
> This email address no longer works, so perhaps just use your own?
Ack, will do.
>
> > + Rajat Jain <[email protected]>
> > +Description:
> > + Information about whether a given device is physically fixed to
> > + the platform. This is determined by the device's subsystem in a
> > + bus / platform-specific way. This attribute is only present for
> > + buses that can support determining such information:
> > +
> > + "removable": The device is external / removable from the system.
> > + "fixed": The device is internal / fixed to the system.
> > + "unknown": The information is unavailable.
> > +
> > + Currently this is only supported by USB (which infers the
> > + information from a combination of hub descriptor bits and
> > + platform-specific data such as ACPI).
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index 4a8bf8cda52b..9e6bf9e71a7e 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -2404,6 +2404,25 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
> > }
> > static DEVICE_ATTR_RW(online);
> >
> > +static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + const char *loc;
> > +
> > + switch (dev->removable) {
> > + case DEVICE_REMOVABLE:
> > + loc = "removable";
> > + break;
> > + case DEVICE_FIXED:
> > + loc = "fixed";
> > + break;
> > + default:
> > + loc = "unknown";
> > + }
> > + return sysfs_emit(buf, "%s\n", loc);
> > +}
> > +static DEVICE_ATTR_RO(removable);
> > +
> > int device_add_groups(struct device *dev, const struct attribute_group **groups)
> > {
> > return sysfs_create_groups(&dev->kobj, groups);
> > @@ -2581,8 +2600,16 @@ static int device_add_attrs(struct device *dev)
> > goto err_remove_dev_online;
> > }
> >
> > + if (type && type->supports_removable) {
> > + error = device_create_file(dev, &dev_attr_removable);
> > + if (error)
> > + goto err_remove_dev_waiting_for_supplier;
> > + }
> > +
> > return 0;
> >
> > + err_remove_dev_waiting_for_supplier:
> > + device_remove_file(dev, &dev_attr_waiting_for_supplier);
> > err_remove_dev_online:
> > device_remove_file(dev, &dev_attr_online);
> > err_remove_dev_groups:
> > @@ -2602,6 +2629,7 @@ static void device_remove_attrs(struct device *dev)
> > struct class *class = dev->class;
> > const struct device_type *type = dev->type;
> >
> > + device_remove_file(dev, &dev_attr_removable);
> > device_remove_file(dev, &dev_attr_waiting_for_supplier);
> > device_remove_file(dev, &dev_attr_online);
> > device_remove_groups(dev, dev->groups);
> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index b2bc4b7c4289..7a3c28b14ca1 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -2443,11 +2443,11 @@ static void set_usb_port_removable(struct usb_device *udev)
> > */
> > switch (hub->ports[udev->portnum - 1]->connect_type) {
> > case USB_PORT_CONNECT_TYPE_HOT_PLUG:
> > - udev->removable = USB_DEVICE_REMOVABLE;
> > + dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
> > return;
> > case USB_PORT_CONNECT_TYPE_HARD_WIRED:
> > case USB_PORT_NOT_USED:
> > - udev->removable = USB_DEVICE_FIXED;
> > + dev_set_removable(&udev->dev, DEVICE_FIXED);
> > return;
> > default:
> > break;
> > @@ -2472,9 +2472,9 @@ static void set_usb_port_removable(struct usb_device *udev)
> > }
> >
> > if (removable)
> > - udev->removable = USB_DEVICE_REMOVABLE;
> > + dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
> > else
> > - udev->removable = USB_DEVICE_FIXED;
> > + dev_set_removable(&udev->dev, DEVICE_FIXED);
> >
> > }
> >
> > diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
> > index 5a168ba9fc51..fa2e49d432ff 100644
> > --- a/drivers/usb/core/sysfs.c
> > +++ b/drivers/usb/core/sysfs.c
> > @@ -301,29 +301,6 @@ static ssize_t urbnum_show(struct device *dev, struct device_attribute *attr,
> > }
> > static DEVICE_ATTR_RO(urbnum);
> >
> > -static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
> > - char *buf)
> > -{
> > - struct usb_device *udev;
> > - char *state;
> > -
> > - udev = to_usb_device(dev);
> > -
> > - switch (udev->removable) {
> > - case USB_DEVICE_REMOVABLE:
> > - state = "removable";
> > - break;
> > - case USB_DEVICE_FIXED:
> > - state = "fixed";
> > - break;
> > - default:
> > - state = "unknown";
> > - }
> > -
> > - return sprintf(buf, "%s\n", state);
> > -}
> > -static DEVICE_ATTR_RO(removable);
> > -
> > static ssize_t ltm_capable_show(struct device *dev,
> > struct device_attribute *attr, char *buf)
> > {
> > @@ -828,7 +805,6 @@ static struct attribute *dev_attrs[] = {
> > &dev_attr_avoid_reset_quirk.attr,
> > &dev_attr_authorized.attr,
> > &dev_attr_remove.attr,
> > - &dev_attr_removable.attr,
> > &dev_attr_ltm_capable.attr,
> > #ifdef CONFIG_OF
> > &dev_attr_devspec.attr,
> > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> > index 62368c4ed37a..ce18e84528cf 100644
> > --- a/drivers/usb/core/usb.c
> > +++ b/drivers/usb/core/usb.c
> > @@ -569,6 +569,7 @@ struct device_type usb_device_type = {
> > #ifdef CONFIG_PM
> > .pm = &usb_device_pm_ops,
> > #endif
> > + .supports_removable = true,
> > };
> >
> >
> > diff --git a/include/linux/device.h b/include/linux/device.h
> > index 38a2071cf776..7e87ab048307 100644
> > --- a/include/linux/device.h
> > +++ b/include/linux/device.h
> > @@ -93,6 +93,8 @@ struct device_type {
> > void (*release)(struct device *dev);
> >
> > const struct dev_pm_ops *pm;
> > +
> > + bool supports_removable:1; /* subsystem can classify removable/fixed */
>
> Why isn't this a bus type? Shouldn't it go there and not in the device
> type?
Please see below.
>
> > };
> >
> > /* interface for exporting device attributes */
> > @@ -350,6 +352,19 @@ enum dl_dev_state {
> > DL_DEV_UNBINDING,
> > };
> >
> > +/**
> > + * enum device_removable - Whether the device is removable. The criteria for a
> > + * device to be classified as removable is determined by its subsystem or bus.
> > + * @DEVICE_REMOVABLE_UNKNOWN: Device location is Unknown (default).
> > + * @DEVICE_REMOVABLE: Device is removable by the user.
> > + * @DEVICE_FIXED: Device is not removable by the user.
> > + */
> > +enum device_removable {
> > + DEVICE_REMOVABLE_UNKNOWN = 0,
> > + DEVICE_REMOVABLE,
> > + DEVICE_FIXED,
> > +};
> > +
> > /**
> > * struct dev_links_info - Device data related to device links.
> > * @suppliers: List of links to supplier devices.
> > @@ -431,6 +446,9 @@ struct dev_links_info {
> > * device (i.e. the bus driver that discovered the device).
> > * @iommu_group: IOMMU group the device belongs to.
> > * @iommu: Per device generic IOMMU runtime data
> > + * @removable: Whether the device can be removed from the system. This
> > + * should be set by the subsystem / bus driver that discovered
> > + * the device.
> > *
> > * @offline_disabled: If set, the device is permanently online.
> > * @offline: Set after successful invocation of bus type's .offline().
> > @@ -544,6 +562,8 @@ struct device {
> > struct iommu_group *iommu_group;
> > struct dev_iommu *iommu;
> >
> > + enum device_removable removable;
> > +
> > bool offline_disabled:1;
> > bool offline:1;
> > bool of_node_reused:1;
> > @@ -782,6 +802,18 @@ static inline bool dev_has_sync_state(struct device *dev)
> > return false;
> > }
> >
> > +static inline void dev_set_removable(struct device *dev,
> > + enum device_removable removable)
> > +{
> > + dev->removable = removable;
> > +}
> > +
> > +static inline bool dev_is_removable(struct device *dev)
> > +{
> > + return dev && dev->type && dev->type->supports_removable
> > + && dev->removable == DEVICE_REMOVABLE;
>
> Again, shouldn't this be a bus type, and not a device type?
>
> Where are you going to have devices of different types on a bus that do,
> or do not, allow this attribute?
USB. Presently, both the usb_device_type and usb_if_device_type sit on
the usb_bus_type but "removable" only applies to usb_device_type (the
attribute shows up only under usb_devices and not under
usb_interfaces).
Thus, I put the supports_removable flag in device_type instead of bus_type.
Thanks,
Rajat
>
> thanks,
>
> greg k-h
On Thu, May 13, 2021 at 9:40 AM Greg Kroah-Hartman
<[email protected]> wrote:
>
> On Thu, May 13, 2021 at 09:26:26AM -0700, Rajat Jain wrote:
> > > > static ssize_t ltm_capable_show(struct device *dev,
> > > > struct device_attribute *attr, char *buf)
> > > > {
> > > > @@ -828,7 +805,6 @@ static struct attribute *dev_attrs[] = {
> > > > &dev_attr_avoid_reset_quirk.attr,
> > > > &dev_attr_authorized.attr,
> > > > &dev_attr_remove.attr,
> > > > - &dev_attr_removable.attr,
> > > > &dev_attr_ltm_capable.attr,
> > > > #ifdef CONFIG_OF
> > > > &dev_attr_devspec.attr,
> > > > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> > > > index 62368c4ed37a..ce18e84528cf 100644
> > > > --- a/drivers/usb/core/usb.c
> > > > +++ b/drivers/usb/core/usb.c
> > > > @@ -569,6 +569,7 @@ struct device_type usb_device_type = {
> > > > #ifdef CONFIG_PM
> > > > .pm = &usb_device_pm_ops,
> > > > #endif
> > > > + .supports_removable = true,
> > > > };
> > > >
> > > >
> > > > diff --git a/include/linux/device.h b/include/linux/device.h
> > > > index 38a2071cf776..7e87ab048307 100644
> > > > --- a/include/linux/device.h
> > > > +++ b/include/linux/device.h
> > > > @@ -93,6 +93,8 @@ struct device_type {
> > > > void (*release)(struct device *dev);
> > > >
> > > > const struct dev_pm_ops *pm;
> > > > +
> > > > + bool supports_removable:1; /* subsystem can classify removable/fixed */
> > >
> > > Why isn't this a bus type? Shouldn't it go there and not in the device
> > > type?
> >
> > Please see below.
> >
> > >
> > > > };
> > > >
> > > > /* interface for exporting device attributes */
> > > > @@ -350,6 +352,19 @@ enum dl_dev_state {
> > > > DL_DEV_UNBINDING,
> > > > };
> > > >
> > > > +/**
> > > > + * enum device_removable - Whether the device is removable. The criteria for a
> > > > + * device to be classified as removable is determined by its subsystem or bus.
> > > > + * @DEVICE_REMOVABLE_UNKNOWN: Device location is Unknown (default).
> > > > + * @DEVICE_REMOVABLE: Device is removable by the user.
> > > > + * @DEVICE_FIXED: Device is not removable by the user.
> > > > + */
> > > > +enum device_removable {
> > > > + DEVICE_REMOVABLE_UNKNOWN = 0,
> > > > + DEVICE_REMOVABLE,
> > > > + DEVICE_FIXED,
> > > > +};
> > > > +
> > > > /**
> > > > * struct dev_links_info - Device data related to device links.
> > > > * @suppliers: List of links to supplier devices.
> > > > @@ -431,6 +446,9 @@ struct dev_links_info {
> > > > * device (i.e. the bus driver that discovered the device).
> > > > * @iommu_group: IOMMU group the device belongs to.
> > > > * @iommu: Per device generic IOMMU runtime data
> > > > + * @removable: Whether the device can be removed from the system. This
> > > > + * should be set by the subsystem / bus driver that discovered
> > > > + * the device.
> > > > *
> > > > * @offline_disabled: If set, the device is permanently online.
> > > > * @offline: Set after successful invocation of bus type's .offline().
> > > > @@ -544,6 +562,8 @@ struct device {
> > > > struct iommu_group *iommu_group;
> > > > struct dev_iommu *iommu;
> > > >
> > > > + enum device_removable removable;
> > > > +
> > > > bool offline_disabled:1;
> > > > bool offline:1;
> > > > bool of_node_reused:1;
> > > > @@ -782,6 +802,18 @@ static inline bool dev_has_sync_state(struct device *dev)
> > > > return false;
> > > > }
> > > >
> > > > +static inline void dev_set_removable(struct device *dev,
> > > > + enum device_removable removable)
> > > > +{
> > > > + dev->removable = removable;
> > > > +}
> > > > +
> > > > +static inline bool dev_is_removable(struct device *dev)
> > > > +{
> > > > + return dev && dev->type && dev->type->supports_removable
> > > > + && dev->removable == DEVICE_REMOVABLE;
> > >
> > > Again, shouldn't this be a bus type, and not a device type?
> > >
> > > Where are you going to have devices of different types on a bus that do,
> > > or do not, allow this attribute?
> >
> > USB. Presently, both the usb_device_type and usb_if_device_type sit on
> > the usb_bus_type but "removable" only applies to usb_device_type (the
> > attribute shows up only under usb_devices and not under
> > usb_interfaces).
>
> Ah. Messy.
>
> Then should this be a per-device value and don't worry about the type at
> all? You have a field in the device already, why not make it:
>
> enum device_removable {
> DEVICE_REMOVABLE_NOT_SUPPORTED = 0, /* must be 0 */
> DEVICE_REMOVABLE_UNKNOWN,
> DEVICE_REMOVABLE,
> DEVICE_FIXED,
> };
>
> And then only show the file if a device does NOT have the value set to
> DEVICE_REMOVABLE_NOT_SUPPORTED?
>
> If a bus/subsystem/whatever wants the device to have a sysfs file and
> value there, then it needs to set it to anything other than 0 and it
> will be created?
Ack, will do.
Thanks,
Rajat
>
> That gets you out of the device bus/type mess and it is localized to
> only the device itself, allowing for any device to do this? Should make
> the logic everywhere a bit simpler as well.
>
> thanks,
>
> greg k-h
On Wed, May 12, 2021 at 02:34:56PM -0700, Rajat Jain wrote:
> Move the "removable" attribute from USB to core in order to allow it to be
> supported by other subsystem / buses. Individual buses that want to support
> this attribute can opt-in by setting the supports_removable flag, and then
> populating the removable property of the device while enumerating it. The
> UAPI (location, symantics etc) for the attribute remains unchanged.
>
> Signed-off-by: Rajat Jain <[email protected]>
> Acked-by: Alan Stern <[email protected]>
> Reviewed-by: Bjorn Helgaas <[email protected]>
> ---
> v3: - Minor commit log / comments updated.
> - use sysfs_emit()
> - Rename local variable name (state -> loc)
> - change supports_removable flag from bool to bitfield.
> v2: Add documentation
>
> Documentation/ABI/testing/sysfs-bus-usb | 11 -------
> .../ABI/testing/sysfs-devices-removable | 17 ++++++++++
> drivers/base/core.c | 28 ++++++++++++++++
> drivers/usb/core/hub.c | 8 ++---
> drivers/usb/core/sysfs.c | 24 --------------
> drivers/usb/core/usb.c | 1 +
> include/linux/device.h | 32 +++++++++++++++++++
> include/linux/usb.h | 7 ----
> 8 files changed, 82 insertions(+), 46 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-devices-removable
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
> index bf2c1968525f..73eb23bc1f34 100644
> --- a/Documentation/ABI/testing/sysfs-bus-usb
> +++ b/Documentation/ABI/testing/sysfs-bus-usb
> @@ -154,17 +154,6 @@ Description:
> files hold a string value (enable or disable) indicating whether
> or not USB3 hardware LPM U1 or U2 is enabled for the device.
>
> -What: /sys/bus/usb/devices/.../removable
> -Date: February 2012
> -Contact: Matthew Garrett <[email protected]>
> -Description:
> - Some information about whether a given USB device is
> - physically fixed to the platform can be inferred from a
> - combination of hub descriptor bits and platform-specific data
> - such as ACPI. This file will read either "removable" or
> - "fixed" if the information is available, and "unknown"
> - otherwise.
> -
> What: /sys/bus/usb/devices/.../ltm_capable
> Date: July 2012
> Contact: Sarah Sharp <[email protected]>
> diff --git a/Documentation/ABI/testing/sysfs-devices-removable b/Documentation/ABI/testing/sysfs-devices-removable
> new file mode 100644
> index 000000000000..9dabcad7cdcd
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-removable
> @@ -0,0 +1,17 @@
> +What: /sys/devices/.../removable
This should be "/sys/bus/devices/.../removable" perhaps? Or not? Is
this moving in the existing USB cases?
> +Date: Apr 2021
> +Contact: Matthew Garrett <[email protected]>,
This email address no longer works, so perhaps just use your own?
> + Rajat Jain <[email protected]>
> +Description:
> + Information about whether a given device is physically fixed to
> + the platform. This is determined by the device's subsystem in a
> + bus / platform-specific way. This attribute is only present for
> + buses that can support determining such information:
> +
> + "removable": The device is external / removable from the system.
> + "fixed": The device is internal / fixed to the system.
> + "unknown": The information is unavailable.
> +
> + Currently this is only supported by USB (which infers the
> + information from a combination of hub descriptor bits and
> + platform-specific data such as ACPI).
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 4a8bf8cda52b..9e6bf9e71a7e 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -2404,6 +2404,25 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
> }
> static DEVICE_ATTR_RW(online);
>
> +static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + const char *loc;
> +
> + switch (dev->removable) {
> + case DEVICE_REMOVABLE:
> + loc = "removable";
> + break;
> + case DEVICE_FIXED:
> + loc = "fixed";
> + break;
> + default:
> + loc = "unknown";
> + }
> + return sysfs_emit(buf, "%s\n", loc);
> +}
> +static DEVICE_ATTR_RO(removable);
> +
> int device_add_groups(struct device *dev, const struct attribute_group **groups)
> {
> return sysfs_create_groups(&dev->kobj, groups);
> @@ -2581,8 +2600,16 @@ static int device_add_attrs(struct device *dev)
> goto err_remove_dev_online;
> }
>
> + if (type && type->supports_removable) {
> + error = device_create_file(dev, &dev_attr_removable);
> + if (error)
> + goto err_remove_dev_waiting_for_supplier;
> + }
> +
> return 0;
>
> + err_remove_dev_waiting_for_supplier:
> + device_remove_file(dev, &dev_attr_waiting_for_supplier);
> err_remove_dev_online:
> device_remove_file(dev, &dev_attr_online);
> err_remove_dev_groups:
> @@ -2602,6 +2629,7 @@ static void device_remove_attrs(struct device *dev)
> struct class *class = dev->class;
> const struct device_type *type = dev->type;
>
> + device_remove_file(dev, &dev_attr_removable);
> device_remove_file(dev, &dev_attr_waiting_for_supplier);
> device_remove_file(dev, &dev_attr_online);
> device_remove_groups(dev, dev->groups);
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index b2bc4b7c4289..7a3c28b14ca1 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -2443,11 +2443,11 @@ static void set_usb_port_removable(struct usb_device *udev)
> */
> switch (hub->ports[udev->portnum - 1]->connect_type) {
> case USB_PORT_CONNECT_TYPE_HOT_PLUG:
> - udev->removable = USB_DEVICE_REMOVABLE;
> + dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
> return;
> case USB_PORT_CONNECT_TYPE_HARD_WIRED:
> case USB_PORT_NOT_USED:
> - udev->removable = USB_DEVICE_FIXED;
> + dev_set_removable(&udev->dev, DEVICE_FIXED);
> return;
> default:
> break;
> @@ -2472,9 +2472,9 @@ static void set_usb_port_removable(struct usb_device *udev)
> }
>
> if (removable)
> - udev->removable = USB_DEVICE_REMOVABLE;
> + dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
> else
> - udev->removable = USB_DEVICE_FIXED;
> + dev_set_removable(&udev->dev, DEVICE_FIXED);
>
> }
>
> diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
> index 5a168ba9fc51..fa2e49d432ff 100644
> --- a/drivers/usb/core/sysfs.c
> +++ b/drivers/usb/core/sysfs.c
> @@ -301,29 +301,6 @@ static ssize_t urbnum_show(struct device *dev, struct device_attribute *attr,
> }
> static DEVICE_ATTR_RO(urbnum);
>
> -static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
> - char *buf)
> -{
> - struct usb_device *udev;
> - char *state;
> -
> - udev = to_usb_device(dev);
> -
> - switch (udev->removable) {
> - case USB_DEVICE_REMOVABLE:
> - state = "removable";
> - break;
> - case USB_DEVICE_FIXED:
> - state = "fixed";
> - break;
> - default:
> - state = "unknown";
> - }
> -
> - return sprintf(buf, "%s\n", state);
> -}
> -static DEVICE_ATTR_RO(removable);
> -
> static ssize_t ltm_capable_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> @@ -828,7 +805,6 @@ static struct attribute *dev_attrs[] = {
> &dev_attr_avoid_reset_quirk.attr,
> &dev_attr_authorized.attr,
> &dev_attr_remove.attr,
> - &dev_attr_removable.attr,
> &dev_attr_ltm_capable.attr,
> #ifdef CONFIG_OF
> &dev_attr_devspec.attr,
> diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> index 62368c4ed37a..ce18e84528cf 100644
> --- a/drivers/usb/core/usb.c
> +++ b/drivers/usb/core/usb.c
> @@ -569,6 +569,7 @@ struct device_type usb_device_type = {
> #ifdef CONFIG_PM
> .pm = &usb_device_pm_ops,
> #endif
> + .supports_removable = true,
> };
>
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 38a2071cf776..7e87ab048307 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -93,6 +93,8 @@ struct device_type {
> void (*release)(struct device *dev);
>
> const struct dev_pm_ops *pm;
> +
> + bool supports_removable:1; /* subsystem can classify removable/fixed */
Why isn't this a bus type? Shouldn't it go there and not in the device
type?
> };
>
> /* interface for exporting device attributes */
> @@ -350,6 +352,19 @@ enum dl_dev_state {
> DL_DEV_UNBINDING,
> };
>
> +/**
> + * enum device_removable - Whether the device is removable. The criteria for a
> + * device to be classified as removable is determined by its subsystem or bus.
> + * @DEVICE_REMOVABLE_UNKNOWN: Device location is Unknown (default).
> + * @DEVICE_REMOVABLE: Device is removable by the user.
> + * @DEVICE_FIXED: Device is not removable by the user.
> + */
> +enum device_removable {
> + DEVICE_REMOVABLE_UNKNOWN = 0,
> + DEVICE_REMOVABLE,
> + DEVICE_FIXED,
> +};
> +
> /**
> * struct dev_links_info - Device data related to device links.
> * @suppliers: List of links to supplier devices.
> @@ -431,6 +446,9 @@ struct dev_links_info {
> * device (i.e. the bus driver that discovered the device).
> * @iommu_group: IOMMU group the device belongs to.
> * @iommu: Per device generic IOMMU runtime data
> + * @removable: Whether the device can be removed from the system. This
> + * should be set by the subsystem / bus driver that discovered
> + * the device.
> *
> * @offline_disabled: If set, the device is permanently online.
> * @offline: Set after successful invocation of bus type's .offline().
> @@ -544,6 +562,8 @@ struct device {
> struct iommu_group *iommu_group;
> struct dev_iommu *iommu;
>
> + enum device_removable removable;
> +
> bool offline_disabled:1;
> bool offline:1;
> bool of_node_reused:1;
> @@ -782,6 +802,18 @@ static inline bool dev_has_sync_state(struct device *dev)
> return false;
> }
>
> +static inline void dev_set_removable(struct device *dev,
> + enum device_removable removable)
> +{
> + dev->removable = removable;
> +}
> +
> +static inline bool dev_is_removable(struct device *dev)
> +{
> + return dev && dev->type && dev->type->supports_removable
> + && dev->removable == DEVICE_REMOVABLE;
Again, shouldn't this be a bus type, and not a device type?
Where are you going to have devices of different types on a bus that do,
or do not, allow this attribute?
thanks,
greg k-h
On Thu, May 13, 2021 at 09:26:26AM -0700, Rajat Jain wrote:
> > > static ssize_t ltm_capable_show(struct device *dev,
> > > struct device_attribute *attr, char *buf)
> > > {
> > > @@ -828,7 +805,6 @@ static struct attribute *dev_attrs[] = {
> > > &dev_attr_avoid_reset_quirk.attr,
> > > &dev_attr_authorized.attr,
> > > &dev_attr_remove.attr,
> > > - &dev_attr_removable.attr,
> > > &dev_attr_ltm_capable.attr,
> > > #ifdef CONFIG_OF
> > > &dev_attr_devspec.attr,
> > > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> > > index 62368c4ed37a..ce18e84528cf 100644
> > > --- a/drivers/usb/core/usb.c
> > > +++ b/drivers/usb/core/usb.c
> > > @@ -569,6 +569,7 @@ struct device_type usb_device_type = {
> > > #ifdef CONFIG_PM
> > > .pm = &usb_device_pm_ops,
> > > #endif
> > > + .supports_removable = true,
> > > };
> > >
> > >
> > > diff --git a/include/linux/device.h b/include/linux/device.h
> > > index 38a2071cf776..7e87ab048307 100644
> > > --- a/include/linux/device.h
> > > +++ b/include/linux/device.h
> > > @@ -93,6 +93,8 @@ struct device_type {
> > > void (*release)(struct device *dev);
> > >
> > > const struct dev_pm_ops *pm;
> > > +
> > > + bool supports_removable:1; /* subsystem can classify removable/fixed */
> >
> > Why isn't this a bus type? Shouldn't it go there and not in the device
> > type?
>
> Please see below.
>
> >
> > > };
> > >
> > > /* interface for exporting device attributes */
> > > @@ -350,6 +352,19 @@ enum dl_dev_state {
> > > DL_DEV_UNBINDING,
> > > };
> > >
> > > +/**
> > > + * enum device_removable - Whether the device is removable. The criteria for a
> > > + * device to be classified as removable is determined by its subsystem or bus.
> > > + * @DEVICE_REMOVABLE_UNKNOWN: Device location is Unknown (default).
> > > + * @DEVICE_REMOVABLE: Device is removable by the user.
> > > + * @DEVICE_FIXED: Device is not removable by the user.
> > > + */
> > > +enum device_removable {
> > > + DEVICE_REMOVABLE_UNKNOWN = 0,
> > > + DEVICE_REMOVABLE,
> > > + DEVICE_FIXED,
> > > +};
> > > +
> > > /**
> > > * struct dev_links_info - Device data related to device links.
> > > * @suppliers: List of links to supplier devices.
> > > @@ -431,6 +446,9 @@ struct dev_links_info {
> > > * device (i.e. the bus driver that discovered the device).
> > > * @iommu_group: IOMMU group the device belongs to.
> > > * @iommu: Per device generic IOMMU runtime data
> > > + * @removable: Whether the device can be removed from the system. This
> > > + * should be set by the subsystem / bus driver that discovered
> > > + * the device.
> > > *
> > > * @offline_disabled: If set, the device is permanently online.
> > > * @offline: Set after successful invocation of bus type's .offline().
> > > @@ -544,6 +562,8 @@ struct device {
> > > struct iommu_group *iommu_group;
> > > struct dev_iommu *iommu;
> > >
> > > + enum device_removable removable;
> > > +
> > > bool offline_disabled:1;
> > > bool offline:1;
> > > bool of_node_reused:1;
> > > @@ -782,6 +802,18 @@ static inline bool dev_has_sync_state(struct device *dev)
> > > return false;
> > > }
> > >
> > > +static inline void dev_set_removable(struct device *dev,
> > > + enum device_removable removable)
> > > +{
> > > + dev->removable = removable;
> > > +}
> > > +
> > > +static inline bool dev_is_removable(struct device *dev)
> > > +{
> > > + return dev && dev->type && dev->type->supports_removable
> > > + && dev->removable == DEVICE_REMOVABLE;
> >
> > Again, shouldn't this be a bus type, and not a device type?
> >
> > Where are you going to have devices of different types on a bus that do,
> > or do not, allow this attribute?
>
> USB. Presently, both the usb_device_type and usb_if_device_type sit on
> the usb_bus_type but "removable" only applies to usb_device_type (the
> attribute shows up only under usb_devices and not under
> usb_interfaces).
Ah. Messy.
Then should this be a per-device value and don't worry about the type at
all? You have a field in the device already, why not make it:
enum device_removable {
DEVICE_REMOVABLE_NOT_SUPPORTED = 0, /* must be 0 */
DEVICE_REMOVABLE_UNKNOWN,
DEVICE_REMOVABLE,
DEVICE_FIXED,
};
And then only show the file if a device does NOT have the value set to
DEVICE_REMOVABLE_NOT_SUPPORTED?
If a bus/subsystem/whatever wants the device to have a sysfs file and
value there, then it needs to set it to anything other than 0 and it
will be created?
That gets you out of the device bus/type mess and it is localized to
only the device itself, allowing for any device to do this? Should make
the logic everywhere a bit simpler as well.
thanks,
greg k-h
Hello,
On Thu, May 13, 2021 at 6:55 AM Greg Kroah-Hartman
<[email protected]> wrote:
>
> On Wed, May 12, 2021 at 02:34:56PM -0700, Rajat Jain wrote:
> > Move the "removable" attribute from USB to core in order to allow it to be
> > supported by other subsystem / buses. Individual buses that want to support
> > this attribute can opt-in by setting the supports_removable flag, and then
> > populating the removable property of the device while enumerating it. The
> > UAPI (location, symantics etc) for the attribute remains unchanged.
> >
> > Signed-off-by: Rajat Jain <[email protected]>
> > Acked-by: Alan Stern <[email protected]>
> > Reviewed-by: Bjorn Helgaas <[email protected]>
> > ---
> > v3: - Minor commit log / comments updated.
> > - use sysfs_emit()
> > - Rename local variable name (state -> loc)
> > - change supports_removable flag from bool to bitfield.
> > v2: Add documentation
> >
> > Documentation/ABI/testing/sysfs-bus-usb | 11 -------
> > .../ABI/testing/sysfs-devices-removable | 17 ++++++++++
> > drivers/base/core.c | 28 ++++++++++++++++
> > drivers/usb/core/hub.c | 8 ++---
> > drivers/usb/core/sysfs.c | 24 --------------
> > drivers/usb/core/usb.c | 1 +
> > include/linux/device.h | 32 +++++++++++++++++++
> > include/linux/usb.h | 7 ----
> > 8 files changed, 82 insertions(+), 46 deletions(-)
> > create mode 100644 Documentation/ABI/testing/sysfs-devices-removable
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
> > index bf2c1968525f..73eb23bc1f34 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-usb
> > +++ b/Documentation/ABI/testing/sysfs-bus-usb
> > @@ -154,17 +154,6 @@ Description:
> > files hold a string value (enable or disable) indicating whether
> > or not USB3 hardware LPM U1 or U2 is enabled for the device.
> >
> > -What: /sys/bus/usb/devices/.../removable
> > -Date: February 2012
> > -Contact: Matthew Garrett <[email protected]>
> > -Description:
> > - Some information about whether a given USB device is
> > - physically fixed to the platform can be inferred from a
> > - combination of hub descriptor bits and platform-specific data
> > - such as ACPI. This file will read either "removable" or
> > - "fixed" if the information is available, and "unknown"
> > - otherwise.
> > -
> > What: /sys/bus/usb/devices/.../ltm_capable
> > Date: July 2012
> > Contact: Sarah Sharp <[email protected]>
> > diff --git a/Documentation/ABI/testing/sysfs-devices-removable b/Documentation/ABI/testing/sysfs-devices-removable
> > new file mode 100644
> > index 000000000000..9dabcad7cdcd
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-devices-removable
> > @@ -0,0 +1,17 @@
> > +What: /sys/devices/.../removable
>
> This should be "/sys/bus/devices/.../removable" perhaps? Or not? Is
> this moving in the existing USB cases?
Sorry, I forgot to respond to this comment earlier today.
There is no /sys/bus/devices/ so I guess you had really meant
"/sys/bus/.../devices/.../removable". Given the latest suggestion on
the patch, where each device shall be free to show / hide this
attribute, I think the current /sys/devices/.../removable looks
correct. Please let me know if you'd still like to change this to
something else, and I'd be happy to change.
Thanks,
Rajat
>
> > +Date: Apr 2021
> > +Contact: Matthew Garrett <[email protected]>,
>
> This email address no longer works, so perhaps just use your own?
>
> > + Rajat Jain <[email protected]>
> > +Description:
> > + Information about whether a given device is physically fixed to
> > + the platform. This is determined by the device's subsystem in a
> > + bus / platform-specific way. This attribute is only present for
> > + buses that can support determining such information:
> > +
> > + "removable": The device is external / removable from the system.
> > + "fixed": The device is internal / fixed to the system.
> > + "unknown": The information is unavailable.
> > +
> > + Currently this is only supported by USB (which infers the
> > + information from a combination of hub descriptor bits and
> > + platform-specific data such as ACPI).
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index 4a8bf8cda52b..9e6bf9e71a7e 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -2404,6 +2404,25 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
> > }
> > static DEVICE_ATTR_RW(online);
> >
> > +static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
> > + char *buf)
> > +{
> > + const char *loc;
> > +
> > + switch (dev->removable) {
> > + case DEVICE_REMOVABLE:
> > + loc = "removable";
> > + break;
> > + case DEVICE_FIXED:
> > + loc = "fixed";
> > + break;
> > + default:
> > + loc = "unknown";
> > + }
> > + return sysfs_emit(buf, "%s\n", loc);
> > +}
> > +static DEVICE_ATTR_RO(removable);
> > +
> > int device_add_groups(struct device *dev, const struct attribute_group **groups)
> > {
> > return sysfs_create_groups(&dev->kobj, groups);
> > @@ -2581,8 +2600,16 @@ static int device_add_attrs(struct device *dev)
> > goto err_remove_dev_online;
> > }
> >
> > + if (type && type->supports_removable) {
> > + error = device_create_file(dev, &dev_attr_removable);
> > + if (error)
> > + goto err_remove_dev_waiting_for_supplier;
> > + }
> > +
> > return 0;
> >
> > + err_remove_dev_waiting_for_supplier:
> > + device_remove_file(dev, &dev_attr_waiting_for_supplier);
> > err_remove_dev_online:
> > device_remove_file(dev, &dev_attr_online);
> > err_remove_dev_groups:
> > @@ -2602,6 +2629,7 @@ static void device_remove_attrs(struct device *dev)
> > struct class *class = dev->class;
> > const struct device_type *type = dev->type;
> >
> > + device_remove_file(dev, &dev_attr_removable);
> > device_remove_file(dev, &dev_attr_waiting_for_supplier);
> > device_remove_file(dev, &dev_attr_online);
> > device_remove_groups(dev, dev->groups);
> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index b2bc4b7c4289..7a3c28b14ca1 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -2443,11 +2443,11 @@ static void set_usb_port_removable(struct usb_device *udev)
> > */
> > switch (hub->ports[udev->portnum - 1]->connect_type) {
> > case USB_PORT_CONNECT_TYPE_HOT_PLUG:
> > - udev->removable = USB_DEVICE_REMOVABLE;
> > + dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
> > return;
> > case USB_PORT_CONNECT_TYPE_HARD_WIRED:
> > case USB_PORT_NOT_USED:
> > - udev->removable = USB_DEVICE_FIXED;
> > + dev_set_removable(&udev->dev, DEVICE_FIXED);
> > return;
> > default:
> > break;
> > @@ -2472,9 +2472,9 @@ static void set_usb_port_removable(struct usb_device *udev)
> > }
> >
> > if (removable)
> > - udev->removable = USB_DEVICE_REMOVABLE;
> > + dev_set_removable(&udev->dev, DEVICE_REMOVABLE);
> > else
> > - udev->removable = USB_DEVICE_FIXED;
> > + dev_set_removable(&udev->dev, DEVICE_FIXED);
> >
> > }
> >
> > diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
> > index 5a168ba9fc51..fa2e49d432ff 100644
> > --- a/drivers/usb/core/sysfs.c
> > +++ b/drivers/usb/core/sysfs.c
> > @@ -301,29 +301,6 @@ static ssize_t urbnum_show(struct device *dev, struct device_attribute *attr,
> > }
> > static DEVICE_ATTR_RO(urbnum);
> >
> > -static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
> > - char *buf)
> > -{
> > - struct usb_device *udev;
> > - char *state;
> > -
> > - udev = to_usb_device(dev);
> > -
> > - switch (udev->removable) {
> > - case USB_DEVICE_REMOVABLE:
> > - state = "removable";
> > - break;
> > - case USB_DEVICE_FIXED:
> > - state = "fixed";
> > - break;
> > - default:
> > - state = "unknown";
> > - }
> > -
> > - return sprintf(buf, "%s\n", state);
> > -}
> > -static DEVICE_ATTR_RO(removable);
> > -
> > static ssize_t ltm_capable_show(struct device *dev,
> > struct device_attribute *attr, char *buf)
> > {
> > @@ -828,7 +805,6 @@ static struct attribute *dev_attrs[] = {
> > &dev_attr_avoid_reset_quirk.attr,
> > &dev_attr_authorized.attr,
> > &dev_attr_remove.attr,
> > - &dev_attr_removable.attr,
> > &dev_attr_ltm_capable.attr,
> > #ifdef CONFIG_OF
> > &dev_attr_devspec.attr,
> > diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> > index 62368c4ed37a..ce18e84528cf 100644
> > --- a/drivers/usb/core/usb.c
> > +++ b/drivers/usb/core/usb.c
> > @@ -569,6 +569,7 @@ struct device_type usb_device_type = {
> > #ifdef CONFIG_PM
> > .pm = &usb_device_pm_ops,
> > #endif
> > + .supports_removable = true,
> > };
> >
> >
> > diff --git a/include/linux/device.h b/include/linux/device.h
> > index 38a2071cf776..7e87ab048307 100644
> > --- a/include/linux/device.h
> > +++ b/include/linux/device.h
> > @@ -93,6 +93,8 @@ struct device_type {
> > void (*release)(struct device *dev);
> >
> > const struct dev_pm_ops *pm;
> > +
> > + bool supports_removable:1; /* subsystem can classify removable/fixed */
>
> Why isn't this a bus type? Shouldn't it go there and not in the device
> type?
>
> > };
> >
> > /* interface for exporting device attributes */
> > @@ -350,6 +352,19 @@ enum dl_dev_state {
> > DL_DEV_UNBINDING,
> > };
> >
> > +/**
> > + * enum device_removable - Whether the device is removable. The criteria for a
> > + * device to be classified as removable is determined by its subsystem or bus.
> > + * @DEVICE_REMOVABLE_UNKNOWN: Device location is Unknown (default).
> > + * @DEVICE_REMOVABLE: Device is removable by the user.
> > + * @DEVICE_FIXED: Device is not removable by the user.
> > + */
> > +enum device_removable {
> > + DEVICE_REMOVABLE_UNKNOWN = 0,
> > + DEVICE_REMOVABLE,
> > + DEVICE_FIXED,
> > +};
> > +
> > /**
> > * struct dev_links_info - Device data related to device links.
> > * @suppliers: List of links to supplier devices.
> > @@ -431,6 +446,9 @@ struct dev_links_info {
> > * device (i.e. the bus driver that discovered the device).
> > * @iommu_group: IOMMU group the device belongs to.
> > * @iommu: Per device generic IOMMU runtime data
> > + * @removable: Whether the device can be removed from the system. This
> > + * should be set by the subsystem / bus driver that discovered
> > + * the device.
> > *
> > * @offline_disabled: If set, the device is permanently online.
> > * @offline: Set after successful invocation of bus type's .offline().
> > @@ -544,6 +562,8 @@ struct device {
> > struct iommu_group *iommu_group;
> > struct dev_iommu *iommu;
> >
> > + enum device_removable removable;
> > +
> > bool offline_disabled:1;
> > bool offline:1;
> > bool of_node_reused:1;
> > @@ -782,6 +802,18 @@ static inline bool dev_has_sync_state(struct device *dev)
> > return false;
> > }
> >
> > +static inline void dev_set_removable(struct device *dev,
> > + enum device_removable removable)
> > +{
> > + dev->removable = removable;
> > +}
> > +
> > +static inline bool dev_is_removable(struct device *dev)
> > +{
> > + return dev && dev->type && dev->type->supports_removable
> > + && dev->removable == DEVICE_REMOVABLE;
>
> Again, shouldn't this be a bus type, and not a device type?
>
> Where are you going to have devices of different types on a bus that do,
> or do not, allow this attribute?
>
> thanks,
>
> greg k-h